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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/9507369 | Jutta Kunz | Guido Nolte, Jutta Kunz and Burkhard Kleihaus | Nondegenerate Fermions in the Background of the Sphaleron Barrier | LATEX, 20 pages, 11 figures | Phys.Rev. D53 (1996) 3451-3459 | 10.1103/PhysRevD.53.3451 | null | hep-ph | null | We consider level crossing in the background of the sphaleron barrier for
nondegenerate fermions. The mass splitting within the fermion doublets allows
only for an axially symmetric ansatz for the fermion fields. In the background
of the sphaleron we solve the partial differential equations for the fermion
functions. We find little angular dependence for our choice of ansatz. We
therefore propose a good approximate ansatz with radial functions only. We
generalize this approximate ansatz with radial functions only to fermions in
the background of the sphaleron barrier and argue, that it is a good
approximation there, too.
| [
{
"created": "Fri, 21 Jul 1995 10:30:38 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Nolte",
"Guido",
""
],
[
"Kunz",
"Jutta",
""
],
[
"Kleihaus",
"Burkhard",
""
]
] | We consider level crossing in the background of the sphaleron barrier for nondegenerate fermions. The mass splitting within the fermion doublets allows only for an axially symmetric ansatz for the fermion fields. In the background of the sphaleron we solve the partial differential equations for the fermion functions. We find little angular dependence for our choice of ansatz. We therefore propose a good approximate ansatz with radial functions only. We generalize this approximate ansatz with radial functions only to fermions in the background of the sphaleron barrier and argue, that it is a good approximation there, too. |
hep-ph/0510021 | Marc Knecht | Karol Kampf, Marc Knecht (CPT), Jiri Novotny | The Dalitz decay pi0 -> e+ e- gamma revisited | null | Eur.Phys.J.C46:191-217,2006 | 10.1140/epjc/s2005-02466-7 | CPT-2004/P.081 | hep-ph | null | The amplitude of the Dalitz decay pi0 -> e+ e gamma is studied and its
model-independent properties are discussed in detail. A calculation of
radiative corrections is performed within the framework of two-flavour chiral
perturbation theory, enlarged by virtual photons and leptons. The lowest meson
dominance approximation, motivated by large N\_C considerations, is used for
the description of the pi0 - gamma* - gamma* transition form factor and for the
estimate of the NLO low energy constants involved in the analysis. The two
photon reducible contributions is included and discussed. Previous calculations
are extended to the whole kinematical range of the soft-photon approximation,
thus allowing for the possibility to consider various experimental situations
and observables.
| [
{
"created": "Mon, 3 Oct 2005 14:25:33 GMT",
"version": "v1"
}
] | 2009-01-07 | [
[
"Kampf",
"Karol",
"",
"CPT"
],
[
"Knecht",
"Marc",
"",
"CPT"
],
[
"Novotny",
"Jiri",
""
]
] | The amplitude of the Dalitz decay pi0 -> e+ e gamma is studied and its model-independent properties are discussed in detail. A calculation of radiative corrections is performed within the framework of two-flavour chiral perturbation theory, enlarged by virtual photons and leptons. The lowest meson dominance approximation, motivated by large N\_C considerations, is used for the description of the pi0 - gamma* - gamma* transition form factor and for the estimate of the NLO low energy constants involved in the analysis. The two photon reducible contributions is included and discussed. Previous calculations are extended to the whole kinematical range of the soft-photon approximation, thus allowing for the possibility to consider various experimental situations and observables. |
2401.10301 | Bodo Lampe | Bodo Lampe | Determination of quark and lepton masses and mixings in the microscopic
model | Contribution to the European Physical Society Conference on High
Energy Physics (EPS-HEP2023), 21-25 August 2023, Hamburg. Part of the
contribution recapitulates results of my earlier original work | Proceedings of The European Physical Society Conference on High
Energy Physics, PoS(EPS-HEP2023), 449 (2024) 373 | 10.22323/1.449.0373 | null | hep-ph hep-ex | http://creativecommons.org/licenses/by-nc-nd/4.0/ | Recently, formulas for the mixing matrices of quarks and leptons have been
put forward. My contribution here describes the relevant foundational and
technical aspects which have led to those results. The work has been carried
out in the framework of the microscopic model. The most general ansatz for the
interactions among tetrons leads to a Hamiltonian H involving
Dzyaloshinskii-Moriya (DM), Heisenberg and torsional isospin forces.
Diagonalization of the Hamiltonian provides for 24 eigenvalues which are
identified as the quark and lepton masses. While the masses of the third and
second family arise from DM and Heisenberg type of isospin interactions, light
family masses are related to torsional interactions among tetrons. Neutrino
masses turn out to be special in that they are given in terms of tiny isospin
non-conserving DM, Heisenberg and torsional couplings. The approach not only
leads to masses, but also allows to calculate the quark and lepton eigenstates,
an issue, which is important for the determination of the CKM and PMNS mixing
matrices. The almost exact isospin conservation of the system dictates the form
of the lepton states and makes them independent of all the couplings in H. Much
in contrast, there is a strong dependence of the quark states on the coupling
strengths, and a promising hierarchy between the quark family mixings shows up.
| [
{
"created": "Thu, 18 Jan 2024 09:46:26 GMT",
"version": "v1"
}
] | 2024-02-05 | [
[
"Lampe",
"Bodo",
""
]
] | Recently, formulas for the mixing matrices of quarks and leptons have been put forward. My contribution here describes the relevant foundational and technical aspects which have led to those results. The work has been carried out in the framework of the microscopic model. The most general ansatz for the interactions among tetrons leads to a Hamiltonian H involving Dzyaloshinskii-Moriya (DM), Heisenberg and torsional isospin forces. Diagonalization of the Hamiltonian provides for 24 eigenvalues which are identified as the quark and lepton masses. While the masses of the third and second family arise from DM and Heisenberg type of isospin interactions, light family masses are related to torsional interactions among tetrons. Neutrino masses turn out to be special in that they are given in terms of tiny isospin non-conserving DM, Heisenberg and torsional couplings. The approach not only leads to masses, but also allows to calculate the quark and lepton eigenstates, an issue, which is important for the determination of the CKM and PMNS mixing matrices. The almost exact isospin conservation of the system dictates the form of the lepton states and makes them independent of all the couplings in H. Much in contrast, there is a strong dependence of the quark states on the coupling strengths, and a promising hierarchy between the quark family mixings shows up. |
0809.5235 | Nikolaos Stefanis | N. G. Stefanis and I. O. Cherednikov | Renormalization-group approach to transverse-momentum dependent parton
distribution functions in QCD | 9 pages, 5 figures, invited plenary talk given by the first author at
XIII International Conference on Selected Problems of Modern Theoretical
Physics, Dubna, Russia, June 23-27, 2008 | null | null | RUB-TPII-07/08 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the renormalization of gauge-invariant transverse-momentum
dependent (TMD), i.e., unintegrated, parton distribution functions (PDFs) and
carry out the calculation of their anomalous dimension at one loop. We show
that in the light-cone gauge, TMD PDFs contain UV divergences that may be
attributed to the renormalization effect on a cusp-like junction point of the
gauge contours at infinity. In order to eliminate the anomalous dimension
ensuing from this cusp, we propose to use in the definition of the TMD PDFs, a
soft counter term in terms of a path-ordered phase factor along a particular
cusped contour extending to transverse light-cone infinity and comprising
light-like and transverse segments. We argue that this additional factor is
analogous to the "intrinsic" Coulomb phase factor found before in QED.
| [
{
"created": "Tue, 30 Sep 2008 16:07:38 GMT",
"version": "v1"
}
] | 2008-10-01 | [
[
"Stefanis",
"N. G.",
""
],
[
"Cherednikov",
"I. O.",
""
]
] | We discuss the renormalization of gauge-invariant transverse-momentum dependent (TMD), i.e., unintegrated, parton distribution functions (PDFs) and carry out the calculation of their anomalous dimension at one loop. We show that in the light-cone gauge, TMD PDFs contain UV divergences that may be attributed to the renormalization effect on a cusp-like junction point of the gauge contours at infinity. In order to eliminate the anomalous dimension ensuing from this cusp, we propose to use in the definition of the TMD PDFs, a soft counter term in terms of a path-ordered phase factor along a particular cusped contour extending to transverse light-cone infinity and comprising light-like and transverse segments. We argue that this additional factor is analogous to the "intrinsic" Coulomb phase factor found before in QED. |
1411.3720 | John Kehayias | Simeon Hellerman, John Kehayias, Tsutomu T. Yanagida | Chaotic Inflation from Nonlinear Sigma Models in Supergravity | 5 pages | Physics Letters B (2015), pp. 390-393 | 10.1016/j.physletb.2015.02.019 | IPMU14-0335 | hep-ph gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a common solution to the puzzles of the light Higgs or quark
masses and the need for a shift symmetry and large field values in high scale
chaotic inflation. One way to protect, for example, the Higgs from a large
supersymmetric mass term is if it is the Nambu-Goldstone boson (NGB) of a
nonlinear sigma model. However, it is well known that nonlinear sigma models
(NLSMs) with nontrivial K\"ahler transformations are problematic to couple to
supergravity. An additional field is necessary to make the K\"ahler potential
of the NLSM invariant in supergravity. This field must have a shift symmetry
--- making it a candidate for the inflaton (or axion). We give an explicit
example of such a model for the coset space $SU(3)/SU(2) \times U(1)$, with the
Higgs as the NGB, including breaking the inflaton's shift symmetry and
producing a chaotic inflation potential. This construction can also be applied
to other models, such as one based on $E_7/SO(10) \times U(1) \times U(1)$
which incorporates the first two generations of (light) quarks as the
Nambu-Goldstone multiplets, and has an axion in addition to the inflaton. Along
the way we clarify and connect previous work on understanding NLSMs in
supergravity and the origin of the extra field (which is the inflaton here),
including a connection to Witten-Bagger quantization. This framework has wide
applications to model building; a light particle from a NLSM requires, in
supergravity, exactly the structure for chaotic inflaton or an axion.
| [
{
"created": "Thu, 13 Nov 2014 21:00:01 GMT",
"version": "v1"
}
] | 2015-02-19 | [
[
"Hellerman",
"Simeon",
""
],
[
"Kehayias",
"John",
""
],
[
"Yanagida",
"Tsutomu T.",
""
]
] | We present a common solution to the puzzles of the light Higgs or quark masses and the need for a shift symmetry and large field values in high scale chaotic inflation. One way to protect, for example, the Higgs from a large supersymmetric mass term is if it is the Nambu-Goldstone boson (NGB) of a nonlinear sigma model. However, it is well known that nonlinear sigma models (NLSMs) with nontrivial K\"ahler transformations are problematic to couple to supergravity. An additional field is necessary to make the K\"ahler potential of the NLSM invariant in supergravity. This field must have a shift symmetry --- making it a candidate for the inflaton (or axion). We give an explicit example of such a model for the coset space $SU(3)/SU(2) \times U(1)$, with the Higgs as the NGB, including breaking the inflaton's shift symmetry and producing a chaotic inflation potential. This construction can also be applied to other models, such as one based on $E_7/SO(10) \times U(1) \times U(1)$ which incorporates the first two generations of (light) quarks as the Nambu-Goldstone multiplets, and has an axion in addition to the inflaton. Along the way we clarify and connect previous work on understanding NLSMs in supergravity and the origin of the extra field (which is the inflaton here), including a connection to Witten-Bagger quantization. This framework has wide applications to model building; a light particle from a NLSM requires, in supergravity, exactly the structure for chaotic inflaton or an axion. |
1611.07377 | Angel Gomez Nicola | Angel Gomez Nicola, Santiago Cortes, John Morales, Jacobo Ruiz de
Elvira, Ricardo Torres Andres | Chiral Symmetry restoration from the hadronic regime | 10 pages, 9 figures. Proceedings of "XII Quark Confinement and the
Hadron Spectrum" | null | 10.1051/epjconf/201713707016 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We discuss recent advances on QCD chiral symmetry restoration at finite
temperature, within the theoretical framework of Effective Theories. $U(3)$
Ward Identities are derived between pseudoscalar susceptibilities and quark
condensates, allowing to explain the behaviour of lattice meson screening
masses. Unitarized interactions and the generated $f_0(500)$ thermal state are
showed to play an essential role in the description of the transition through
the scalar susceptibility
| [
{
"created": "Tue, 22 Nov 2016 15:59:38 GMT",
"version": "v1"
}
] | 2017-04-05 | [
[
"Nicola",
"Angel Gomez",
""
],
[
"Cortes",
"Santiago",
""
],
[
"Morales",
"John",
""
],
[
"de Elvira",
"Jacobo Ruiz",
""
],
[
"Andres",
"Ricardo Torres",
""
]
] | We discuss recent advances on QCD chiral symmetry restoration at finite temperature, within the theoretical framework of Effective Theories. $U(3)$ Ward Identities are derived between pseudoscalar susceptibilities and quark condensates, allowing to explain the behaviour of lattice meson screening masses. Unitarized interactions and the generated $f_0(500)$ thermal state are showed to play an essential role in the description of the transition through the scalar susceptibility |
hep-ph/0208095 | Arlene Cristina Aguilar | A.C. Aguilar, A. Mihara and A.A. Natale (IFT/Unesp-Brazil) | Phenomenological tests for the freezing of the QCD running coupling
constant | 15 pages, 8 figures | null | null | null | hep-ph | null | We discuss phenomenological tests for the frozen infrared behavior of the
running coupling constant and gluon propagators found in some solutions of
Schwinger-Dyson equations of the gluonic sector of QCD. We verify that several
observables can be used in order to select the different expressions of alpha_s
found in the literature. We test the effect of the nonperturbative coupling in
the tau-lepton decay rate into nonstrange hadrons, in the rho vector meson
helicity density matrix that are produced in the chi_{c2} --> rho rho decay, in
the photon to pion transition form factor, and compute the cross sections for
elastic proton-proton scattering and exclusive rho production in deep inelastic
scattering. These quantities depend on the infrared behavior of the coupling
constant at different levels, we discuss the reasons for this dependence and
argue that the existent and future data can be used to test the approximations
performed to solve the Schwinger-Dyson equations and they already seems to
select one specific infrared behavior of the coupling.
| [
{
"created": "Fri, 9 Aug 2002 19:58:47 GMT",
"version": "v1"
},
{
"created": "Sat, 24 May 2003 20:26:06 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Aguilar",
"A. C.",
"",
"IFT/Unesp-Brazil"
],
[
"Mihara",
"A.",
"",
"IFT/Unesp-Brazil"
],
[
"Natale",
"A. A.",
"",
"IFT/Unesp-Brazil"
]
] | We discuss phenomenological tests for the frozen infrared behavior of the running coupling constant and gluon propagators found in some solutions of Schwinger-Dyson equations of the gluonic sector of QCD. We verify that several observables can be used in order to select the different expressions of alpha_s found in the literature. We test the effect of the nonperturbative coupling in the tau-lepton decay rate into nonstrange hadrons, in the rho vector meson helicity density matrix that are produced in the chi_{c2} --> rho rho decay, in the photon to pion transition form factor, and compute the cross sections for elastic proton-proton scattering and exclusive rho production in deep inelastic scattering. These quantities depend on the infrared behavior of the coupling constant at different levels, we discuss the reasons for this dependence and argue that the existent and future data can be used to test the approximations performed to solve the Schwinger-Dyson equations and they already seems to select one specific infrared behavior of the coupling. |
1107.2130 | Vojt\v{e}ch Krej\v{c}i\v{r}\'ik | Thomas D. Cohen and Vojt\v{e}ch Krej\v{c}i\v{r}\'ik | Does the empirical meson spectrum support the Hagedorn conjecture? | null | J. Phys. G: Nucl. Part. Phys. 39 (2012) 055001 | 10.1088/0954-3899/39/5/055001 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has long been conjectured that strong interactions give rise to a Hagedorn
spectrum and theoretical arguments have been presented in support of Hagedorn
spectrum in large $N_c$ QCD. This paper discusses the extent to which the meson
spectrum should be viewed as evidence for a Hagedorn spectrum and argues that
data do not provide a strong evidence for the Hagedorn conjecture. The
conclusion is based on three reasons. It is shown that "realistic" quark models
have a spectrum in which the number of mesons up to 2.3 GeV grows with mass in
a very similar way to the spectrum of physical mesons up to 2.3 GeV. However,
these models can be shown not to have Hagedorn spectra. It is also shown that
the available data are insufficient to determine the Hagedorn temperature. The
data can be described with comparable accuracy by various functional forms of
the prefactor that yield radically different Hagedorn temperatures. An analysis
of the behavior of the spectrum for the various parity-spin-charge
conjugation-isospin channels also appears to be inconsistent with what one
expects if the data were in the regime dominated by exponential behavior.
| [
{
"created": "Mon, 11 Jul 2011 20:07:21 GMT",
"version": "v1"
},
{
"created": "Wed, 20 Jul 2011 19:05:00 GMT",
"version": "v2"
},
{
"created": "Mon, 26 Sep 2011 18:24:42 GMT",
"version": "v3"
},
{
"created": "Mon, 31 Oct 2011 17:15:09 GMT",
"version": "v4"
},
{
"c... | 2012-03-26 | [
[
"Cohen",
"Thomas D.",
""
],
[
"Krejčiřík",
"Vojtěch",
""
]
] | It has long been conjectured that strong interactions give rise to a Hagedorn spectrum and theoretical arguments have been presented in support of Hagedorn spectrum in large $N_c$ QCD. This paper discusses the extent to which the meson spectrum should be viewed as evidence for a Hagedorn spectrum and argues that data do not provide a strong evidence for the Hagedorn conjecture. The conclusion is based on three reasons. It is shown that "realistic" quark models have a spectrum in which the number of mesons up to 2.3 GeV grows with mass in a very similar way to the spectrum of physical mesons up to 2.3 GeV. However, these models can be shown not to have Hagedorn spectra. It is also shown that the available data are insufficient to determine the Hagedorn temperature. The data can be described with comparable accuracy by various functional forms of the prefactor that yield radically different Hagedorn temperatures. An analysis of the behavior of the spectrum for the various parity-spin-charge conjugation-isospin channels also appears to be inconsistent with what one expects if the data were in the regime dominated by exponential behavior. |
2008.13621 | Hrishabh Bharadwaj | Hrishabh Bharadwaj and Ashok Goyal | Effective Field Theory approach to lepto-philic self conjugate dark
matter | 21 pages, 10 figures. To be published in Chinese Physics C. arXiv
admin note: text overlap with arXiv:1901.00192 | Chinese Physics C Vol. 45, No. 2 (2021) 023114 | 10.1088/1674-1137/abce50 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the self conjugate dark matter (DM) particles interacting primarily
with the standard model leptons in an effective field theoretical frame work.
We consider SM gauge invariant effective contact interactions between the
Majorana fermion, real scalar and a real vector DM with leptons by evaluating
the Wilson coefficients appropriate for interaction terms upto dimension-8 and
obtain constraints on the parameters of the theory from the observed relic
density, indirect detection observations and from the DM-electron scattering
cross-sections in the direct detection experiments. Low energy LEP data has
been used to study sensitivity in the pair production of such low mass $\le$ 80
GeV DM particles. Pair production of DM particles of mass $\ge$ 50 GeV in
association with mono-photons at the proposed ILC has rich potential to probe
such effective operators.
| [
{
"created": "Fri, 28 Aug 2020 06:53:51 GMT",
"version": "v1"
},
{
"created": "Tue, 3 Nov 2020 13:41:47 GMT",
"version": "v2"
}
] | 2021-01-27 | [
[
"Bharadwaj",
"Hrishabh",
""
],
[
"Goyal",
"Ashok",
""
]
] | We study the self conjugate dark matter (DM) particles interacting primarily with the standard model leptons in an effective field theoretical frame work. We consider SM gauge invariant effective contact interactions between the Majorana fermion, real scalar and a real vector DM with leptons by evaluating the Wilson coefficients appropriate for interaction terms upto dimension-8 and obtain constraints on the parameters of the theory from the observed relic density, indirect detection observations and from the DM-electron scattering cross-sections in the direct detection experiments. Low energy LEP data has been used to study sensitivity in the pair production of such low mass $\le$ 80 GeV DM particles. Pair production of DM particles of mass $\ge$ 50 GeV in association with mono-photons at the proposed ILC has rich potential to probe such effective operators. |
hep-ph/9804342 | Kunihiko Terasaki | K. Terasaki | Twopion decays of K mesons, K_L-K_S mass difference and the Dalitz
decays of K_L | 15 pages, LaTex | null | null | YITP-98-26 | hep-ph | null | Two pion Decays of K mesons, K_L-K_S mass difference, two photon decay and
the Dalitz decays of K_L are studied systematically by assuming that their
amplitude can be described in terms of a sum of short distance and long
distance contributions. Dominance of the short distance effect on the K_L-K_S
mass difference will be checked by the Dalitz decays of K_L in a way consisten
with the two pion decays of K mesons and the two photon decay of K_L.
| [
{
"created": "Tue, 21 Apr 1998 05:56:48 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Terasaki",
"K.",
""
]
] | Two pion Decays of K mesons, K_L-K_S mass difference, two photon decay and the Dalitz decays of K_L are studied systematically by assuming that their amplitude can be described in terms of a sum of short distance and long distance contributions. Dominance of the short distance effect on the K_L-K_S mass difference will be checked by the Dalitz decays of K_L in a way consisten with the two pion decays of K mesons and the two photon decay of K_L. |
1109.1936 | Jose Rodriguez-Quintero | Ph. Boucaud, J. P. Leroy, A. Le Yaouanc, J. Micheli, O. P\'ene, J.
Rodr\'iguez-Quintero | The Infrared Behaviour of the Pure Yang-Mills Green Functions | Final version to be published in FBS (54 pgs., 11 figs., 4 tabs) | null | 10.1007/s00601-011-0301-2 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review the infrared properties of the pure Yang-Mills correlators and
discuss recent results concerning the two classes of low-momentum solutions for
them reported in literature; i.e. decoupling and scaling solutions. We will
mainly focuss on the Landau gauge and pay special attention to the results
inferred from the analysis of the Dyson-Schwinger equations of the theory and
from "{\it quenched}" lattice QCD. The results obtained from properly
interplaying both approaches are strongly emphasized.
| [
{
"created": "Fri, 9 Sep 2011 08:27:35 GMT",
"version": "v1"
},
{
"created": "Thu, 19 Jan 2012 15:00:21 GMT",
"version": "v2"
}
] | 2015-05-30 | [
[
"Boucaud",
"Ph.",
""
],
[
"Leroy",
"J. P.",
""
],
[
"Yaouanc",
"A. Le",
""
],
[
"Micheli",
"J.",
""
],
[
"Péne",
"O.",
""
],
[
"Rodríguez-Quintero",
"J.",
""
]
] | We review the infrared properties of the pure Yang-Mills correlators and discuss recent results concerning the two classes of low-momentum solutions for them reported in literature; i.e. decoupling and scaling solutions. We will mainly focuss on the Landau gauge and pay special attention to the results inferred from the analysis of the Dyson-Schwinger equations of the theory and from "{\it quenched}" lattice QCD. The results obtained from properly interplaying both approaches are strongly emphasized. |
0810.0889 | Yoshitaka Hatta | Yoshitaka Hatta | Relating $e^+e^-$ annihilation to high energy scattering at weak and
strong coupling | 16 pages; v2. minor corrections, one reference added | JHEP 0811:057,2008 | 10.1088/1126-6708/2008/11/057 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We explore the correspondence between the final state in e^+e^- annihilation
and the small-x hadronic wavefunction in the transverse plane both in weakly
coupled QCD and strongly coupled N=4 SYM. At strong coupling, the virtual and
static photon produced in e^+e^- annihilation can be treated as a shock wave
propagating in AdS space leaving spherical energy and charge distributions on
the boundary. This is shown to be mathematically identical to the computation
of energy and charge distributions in the transverse plane generated by a high
energy color singlet state. At weak coupling, the correspondence is useful in
studying interjet observables. By performing the stereographic projection to
the BFKL equation, we construct an exact solution to the evolution equation
derived by Marchesini and Mueller, and find the angular distribution of small-x
gluons in the interjet region. Finally we argue that the correspondence holds
also for the energy correlation functions.
| [
{
"created": "Mon, 6 Oct 2008 06:43:28 GMT",
"version": "v1"
},
{
"created": "Thu, 30 Oct 2008 01:57:46 GMT",
"version": "v2"
}
] | 2010-04-21 | [
[
"Hatta",
"Yoshitaka",
""
]
] | We explore the correspondence between the final state in e^+e^- annihilation and the small-x hadronic wavefunction in the transverse plane both in weakly coupled QCD and strongly coupled N=4 SYM. At strong coupling, the virtual and static photon produced in e^+e^- annihilation can be treated as a shock wave propagating in AdS space leaving spherical energy and charge distributions on the boundary. This is shown to be mathematically identical to the computation of energy and charge distributions in the transverse plane generated by a high energy color singlet state. At weak coupling, the correspondence is useful in studying interjet observables. By performing the stereographic projection to the BFKL equation, we construct an exact solution to the evolution equation derived by Marchesini and Mueller, and find the angular distribution of small-x gluons in the interjet region. Finally we argue that the correspondence holds also for the energy correlation functions. |
hep-ph/0507326 | Yadong Yang | Ya-Dong Yang, Fang Su, Gong-Ru Lu and Hong-Jun Hao | Revisiting the annihilation decay $\bar{B}_{s}\to\pi^{+}\pi^{-}$ | 9 pages, 3 eps figures. To appear in EPJC | Eur.Phys.J.C44:243-247,2005 | 10.1140/epjc/s2005-02364-0 | null | hep-ph | null | It is very important to know the strength of annihilation contribution in B
charmless nonleptonic decays. $\bar{B}_{s}\to \pi^{+}\pi^{-}$ process could
serve a good probe of the strength. We have studied the process in QCD
factorization framework. Using a gluon mass scale indicted by the studies of
infrared behavior of gluon propagators to avoid enhancements in the soft end
point regions, we find that the CP averaged branching ratio is about
$1.24\times 10^{-7}$, the direct CP asymmetry $C_{\pi\pi}$ is about -0.05,
while the mixing-induced CP asymmetry quite large with the value
$S_{\pi\pi}$=0.18. The process could be measured at LHC-b experiments in the
near future and would deepen our understanding of dynamics of B charmless
decays.
| [
{
"created": "Thu, 28 Jul 2005 18:20:49 GMT",
"version": "v1"
}
] | 2009-01-07 | [
[
"Yang",
"Ya-Dong",
""
],
[
"Su",
"Fang",
""
],
[
"Lu",
"Gong-Ru",
""
],
[
"Hao",
"Hong-Jun",
""
]
] | It is very important to know the strength of annihilation contribution in B charmless nonleptonic decays. $\bar{B}_{s}\to \pi^{+}\pi^{-}$ process could serve a good probe of the strength. We have studied the process in QCD factorization framework. Using a gluon mass scale indicted by the studies of infrared behavior of gluon propagators to avoid enhancements in the soft end point regions, we find that the CP averaged branching ratio is about $1.24\times 10^{-7}$, the direct CP asymmetry $C_{\pi\pi}$ is about -0.05, while the mixing-induced CP asymmetry quite large with the value $S_{\pi\pi}$=0.18. The process could be measured at LHC-b experiments in the near future and would deepen our understanding of dynamics of B charmless decays. |
1905.08498 | Rui-Xiang Shi | Rui-Xiang Shi, Li-Sheng Geng, Benjam\'in Grinstein, Sebastian J\"ager,
and Jorge Martin Camalich | Revisiting the new-physics interpretation of the $b\to c\tau\nu$ data | matches publised version | JHEP 12 (2019) 065 | 10.1007/JHEP12(2019)065 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We revisit the status of the new-physics interpretations of the anomalies in
semileptonic $B$ decays in light of the new data reported by Belle on the
lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the
longitudinal polarization of the $D^*$ in $B\to D^*\tau\nu$, $F_L^{D^*}$. The
preferred solutions involve new left-handed currents or tensor contributions.
Interpretations with pure right-handed currents are disfavored by the LHC data,
while pure scalar models are disfavored by the upper limits derived either from
the LHC or from the $B_c$ lifetime. The observable $F_L^{D^*}$ also gives an
important constraint leading to the exclusion of large regions of parameter
space. Finally, we investigate the sensitivity of different observables to the
various scenarios and conclude that a measurement of the tau polarization in
the decay mode $B\to D\tau\nu$ would effectively discriminate among them.
| [
{
"created": "Tue, 21 May 2019 08:42:40 GMT",
"version": "v1"
},
{
"created": "Thu, 25 Jul 2019 08:32:22 GMT",
"version": "v2"
},
{
"created": "Sun, 22 Dec 2019 19:53:58 GMT",
"version": "v3"
}
] | 2019-12-24 | [
[
"Shi",
"Rui-Xiang",
""
],
[
"Geng",
"Li-Sheng",
""
],
[
"Grinstein",
"Benjamín",
""
],
[
"Jäger",
"Sebastian",
""
],
[
"Camalich",
"Jorge Martin",
""
]
] | We revisit the status of the new-physics interpretations of the anomalies in semileptonic $B$ decays in light of the new data reported by Belle on the lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the longitudinal polarization of the $D^*$ in $B\to D^*\tau\nu$, $F_L^{D^*}$. The preferred solutions involve new left-handed currents or tensor contributions. Interpretations with pure right-handed currents are disfavored by the LHC data, while pure scalar models are disfavored by the upper limits derived either from the LHC or from the $B_c$ lifetime. The observable $F_L^{D^*}$ also gives an important constraint leading to the exclusion of large regions of parameter space. Finally, we investigate the sensitivity of different observables to the various scenarios and conclude that a measurement of the tau polarization in the decay mode $B\to D\tau\nu$ would effectively discriminate among them. |
2306.07343 | Aman Gupta | Aman Gupta, Debasish Majumdar, Suprabh Prakash | Neutrino oscillation measurements with KamLAND and JUNO in the presence
of scalar NSI | 25 pages, 6 figures. In the previous version, density subtraction was
not done and robustness of standard oscillation parameters was assumed. In
this version, we first constrain the solar oscillation parameters using
KamLAND data and then reassess the potential of JUNO towards neutrino
oscillation measurements in the presence of scalar NSI. Our results and
conclusion have changed | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Determination of neutrino mass ordering and precision measurement of neutrino
oscillation parameters are the foremost goals of the JUNO experiment. Here, we
explore the effects of scalar non-standard interactions (sNSI) on the electron
neutrino survival probability measured by JUNO. sNSI appears as a correction to
the neutrino mass term in the Hamiltonian. We have considered the simplest
scenario where there is only one NSI ($\eta_{ee}$) present in the theory. Our
results show that sNSI can have significant effect on neutrino oscillation
probabilities at the medium- and long-baseline reactor experiments. We fit
KamLAND data assuming non-zero sNSI in theory and find that {\it estimates of
$\Delta m^2_{21}$ and $\theta_{12}$ from KamLAND deviate significantly from
their standard best-fit values} if one assumes sNSI in the theory. $\eta_{ee}
\in [-1.0, 1.0]$ is allowed by KamLAND. JUNO cannot constrain sNSI but it can
robustly measure $\Delta m^2_{21}$ and $\theta_{12}$ even when they differ
widely from their current best-fit values. {\it Our works highlight the
necessity of global analysis of constraints on sNSI and standard two-flavour
oscillation parameters before arduous three-flavour questions such as neutrino
mass ordering or CP violation in their presence is attempted.
| [
{
"created": "Mon, 12 Jun 2023 18:05:00 GMT",
"version": "v1"
},
{
"created": "Mon, 24 Jul 2023 11:16:22 GMT",
"version": "v2"
},
{
"created": "Fri, 2 Aug 2024 18:44:16 GMT",
"version": "v3"
}
] | 2024-08-06 | [
[
"Gupta",
"Aman",
""
],
[
"Majumdar",
"Debasish",
""
],
[
"Prakash",
"Suprabh",
""
]
] | Determination of neutrino mass ordering and precision measurement of neutrino oscillation parameters are the foremost goals of the JUNO experiment. Here, we explore the effects of scalar non-standard interactions (sNSI) on the electron neutrino survival probability measured by JUNO. sNSI appears as a correction to the neutrino mass term in the Hamiltonian. We have considered the simplest scenario where there is only one NSI ($\eta_{ee}$) present in the theory. Our results show that sNSI can have significant effect on neutrino oscillation probabilities at the medium- and long-baseline reactor experiments. We fit KamLAND data assuming non-zero sNSI in theory and find that {\it estimates of $\Delta m^2_{21}$ and $\theta_{12}$ from KamLAND deviate significantly from their standard best-fit values} if one assumes sNSI in the theory. $\eta_{ee} \in [-1.0, 1.0]$ is allowed by KamLAND. JUNO cannot constrain sNSI but it can robustly measure $\Delta m^2_{21}$ and $\theta_{12}$ even when they differ widely from their current best-fit values. {\it Our works highlight the necessity of global analysis of constraints on sNSI and standard two-flavour oscillation parameters before arduous three-flavour questions such as neutrino mass ordering or CP violation in their presence is attempted. |
2310.18990 | Robert J. Perry | {\L}ukasz Bibrzycki, Nadine Hammoud, Vincent Mathieu, Robert J. Perry,
Adam P. Szczepaniak | Studying the production mechanisms of light meson resonances in two-pion
photoproduction: a Regge approach | 5 pages, 3 figures. Prepared as proceedings contribution for the 20th
International Conference on Hadron Spectroscopy and Structure (HADRON 2023),
Genova, Italy, 5-9/6/2023 | null | null | Hadron23 | hep-ph nucl-th | http://creativecommons.org/licenses/by/4.0/ | A calculation of the angular moments of two-pion photoproduction is
presented. The underlying theoretical model encodes the prominent $\rho(770)$
resonance and the expected leading background contribution coming from the Deck
mechanism. The model contains a number of free parameters which are fit to
experimental data. A good description of the angular moments is obtained.
| [
{
"created": "Sun, 29 Oct 2023 12:17:29 GMT",
"version": "v1"
}
] | 2023-10-31 | [
[
"Bibrzycki",
"Łukasz",
""
],
[
"Hammoud",
"Nadine",
""
],
[
"Mathieu",
"Vincent",
""
],
[
"Perry",
"Robert J.",
""
],
[
"Szczepaniak",
"Adam P.",
""
]
] | A calculation of the angular moments of two-pion photoproduction is presented. The underlying theoretical model encodes the prominent $\rho(770)$ resonance and the expected leading background contribution coming from the Deck mechanism. The model contains a number of free parameters which are fit to experimental data. A good description of the angular moments is obtained. |
hep-ph/9809297 | Yasuhiro Okada | Yasuhiro Okada (KEK) | Flavor Physics in the Supergravity Model | 10 pages, 3 figures, talk presented at International Seminar
``Quarks' 98'', Suzdal, Russia, May 17 - 24, 1998 | null | null | KEK-TH-593 | hep-ph | null | Phenomenological aspects of flavor changing processes are considered in the
context of the supergravity model.Various flavor changing neutral current
processes in B and K decays are calculated in such models. For lepton flavor
violating processes the $\mu^+ \to e \gamma$ branching ratio and the T odd
triple vector correlation for the $\mu^+ \to e^+ e^+ e^-$ process are
investigated in the SU(5) SUSY GUT. Possibility to find SUSY effects through
these Flavor changing processes in future experiments are also discussed.
| [
{
"created": "Tue, 8 Sep 1998 08:50:17 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Okada",
"Yasuhiro",
"",
"KEK"
]
] | Phenomenological aspects of flavor changing processes are considered in the context of the supergravity model.Various flavor changing neutral current processes in B and K decays are calculated in such models. For lepton flavor violating processes the $\mu^+ \to e \gamma$ branching ratio and the T odd triple vector correlation for the $\mu^+ \to e^+ e^+ e^-$ process are investigated in the SU(5) SUSY GUT. Possibility to find SUSY effects through these Flavor changing processes in future experiments are also discussed. |
2003.13302 | Nagisa Hiroshima | Takuya Hasegawa, Nagisa Hiroshima, Kazunori Kohri, Rasmus S. L.
Hansen, Thomas Tram, Steen Hannestad | MeV-scale reheating temperature and cosmological production of light
sterile neutrinos | 33 pages, 10 figures, to appear in JCAP | JCAP 08 (2020) 015 | 10.1088/1475-7516/2020/08/015 | RIKEN-iTHEMS-Report-20, UT-HET 132, KEK-Cosmo-251, KEK-TH-2204,
IPMU20-0038 | hep-ph astro-ph.CO | http://creativecommons.org/licenses/by/4.0/ | We investigate how sterile neutrinos with a range of masses influence
cosmology in MeV-scale reheating temperature scenarios. By computing the
production of sterile neutrinos through the combination of mixing and
scattering in the early Universe, we find that light sterile neutrinos, with
masses and mixings as inferred from short-baseline neutrino oscillation
experiments, are consistent with big-bang nucleosynthesis (BBN) and cosmic
microwave background (CMB) radiation for the reheating temperature of ${\cal
O}(1)$ MeV if the parent particle responsible for reheating decays into
electromagnetic components (radiative decay). In contrast, if the parent
particle mainly decays into hadrons (hadronic decay), the bound from BBN
becomes more stringent. In this case, the existence of the light sterile
neutrinos can be cosmologically excluded, depending on the mass and the
hadronic branching ratio of the parent particle.
| [
{
"created": "Mon, 30 Mar 2020 09:47:26 GMT",
"version": "v1"
},
{
"created": "Thu, 6 Aug 2020 22:01:14 GMT",
"version": "v2"
}
] | 2020-08-13 | [
[
"Hasegawa",
"Takuya",
""
],
[
"Hiroshima",
"Nagisa",
""
],
[
"Kohri",
"Kazunori",
""
],
[
"Hansen",
"Rasmus S. L.",
""
],
[
"Tram",
"Thomas",
""
],
[
"Hannestad",
"Steen",
""
]
] | We investigate how sterile neutrinos with a range of masses influence cosmology in MeV-scale reheating temperature scenarios. By computing the production of sterile neutrinos through the combination of mixing and scattering in the early Universe, we find that light sterile neutrinos, with masses and mixings as inferred from short-baseline neutrino oscillation experiments, are consistent with big-bang nucleosynthesis (BBN) and cosmic microwave background (CMB) radiation for the reheating temperature of ${\cal O}(1)$ MeV if the parent particle responsible for reheating decays into electromagnetic components (radiative decay). In contrast, if the parent particle mainly decays into hadrons (hadronic decay), the bound from BBN becomes more stringent. In this case, the existence of the light sterile neutrinos can be cosmologically excluded, depending on the mass and the hadronic branching ratio of the parent particle. |
hep-ph/9810292 | Graham E. Smye | Graham E. Smye | Power Corrections to Flavour-Singlet Structure Functions | 13 pages, 3 figures | Nucl.Phys. B546 (1999) 315-329 | 10.1016/S0550-3213(99)00043-7 | Cavendish-HEP-98/14 | hep-ph | null | We investigate the power-suppressed corrections to structure functions in
flavour singlet deep inelastic lepton scattering, to complement the previous
results for the non-singlet contribution. Our method is a dispersive approach
based on an analysis of Feynman graphs containing massive gluons; and our
results agree with those obtained from leading infrared renormalon
contributions. As in non-singlet deep inelastic scattering we find that the
leading corrections are proportional to 1/Q^2. We find that the singlet
contribution becomes important at small x.
| [
{
"created": "Thu, 8 Oct 1998 15:03:57 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Smye",
"Graham E.",
""
]
] | We investigate the power-suppressed corrections to structure functions in flavour singlet deep inelastic lepton scattering, to complement the previous results for the non-singlet contribution. Our method is a dispersive approach based on an analysis of Feynman graphs containing massive gluons; and our results agree with those obtained from leading infrared renormalon contributions. As in non-singlet deep inelastic scattering we find that the leading corrections are proportional to 1/Q^2. We find that the singlet contribution becomes important at small x. |
hep-ph/9503358 | Leszek Roszkowski | L. Roszkowski and M. Shifman | Reconciling Supersymmetric Grand Unification with $\alpha_s(m_Z)\approx
0.11$ | 18 pages, LaTex format for text; epsf.sty needed for including 3
Postscript figures in the text. CHANGES: Comments on dark matter and
non-minimal supergravity (see end of Sec. 2.3) and several references added;
also some minor corrections made. | Phys.Rev. D53 (1996) 404-412 | 10.1103/PhysRevD.53.404 | TPI-MINN-95/04-T, UMN-TH-1330-95 | hep-ph | null | We argue that supersymmetric grand unification of gauge couplings is not
incompatible with small $\alpha_s$, even without large GUT-scale corrections,
if one relaxes a usual universal gaugino mass assumption. A commonly assumed
relation $M_2\simeq m_{\rm gluino}/3$ is in gross contradiction with
$\alpha_s\approx 0.11$. Instead, small $\alpha_s$ favors $M_2\gg m_{\rm
gluino}$. If this is indeed the case our observation casts doubt on another
commonly used relation $M_1\simeq 0.5 M_2$ which originates from the same
constraint of a common gaugino mass at the GUT scale. One firm prediction
emerging within the small $\alpha_s$ scenario with the unconstrained gaugino
masses is the existence of a relatively light gluino below $\sim$ 200\gev.
| [
{
"created": "Thu, 16 Mar 1995 23:46:24 GMT",
"version": "v1"
},
{
"created": "Thu, 30 Mar 1995 19:57:56 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Roszkowski",
"L.",
""
],
[
"Shifman",
"M.",
""
]
] | We argue that supersymmetric grand unification of gauge couplings is not incompatible with small $\alpha_s$, even without large GUT-scale corrections, if one relaxes a usual universal gaugino mass assumption. A commonly assumed relation $M_2\simeq m_{\rm gluino}/3$ is in gross contradiction with $\alpha_s\approx 0.11$. Instead, small $\alpha_s$ favors $M_2\gg m_{\rm gluino}$. If this is indeed the case our observation casts doubt on another commonly used relation $M_1\simeq 0.5 M_2$ which originates from the same constraint of a common gaugino mass at the GUT scale. One firm prediction emerging within the small $\alpha_s$ scenario with the unconstrained gaugino masses is the existence of a relatively light gluino below $\sim$ 200\gev. |
hep-ph/0511177 | Walter Winter | Thomas Schwetz, Walter Winter | Testing mass-varying neutrinos with reactor experiments | 7 pages, 3 figures, 1 table, uses espcrc2.sty | Phys.Lett. B633 (2006) 557-562 | 10.1016/j.physletb.2005.12.052 | SISSA 86/2005/EP | hep-ph hep-ex | null | We propose that reactor experiments could be used to constrain the
environment dependence of neutrino mass and mixing parameters, which could be
induced due to an acceleron coupling to matter fields. There are several
short-baseline reactor experiment projects with different fractions of air and
earth matter along the neutrino path. Moreover, the short baselines, in
principle, allow the physical change of the material between source and
detector. Hence, such experiments offer the possibility for a direct comparison
of oscillations in air and matter. We demonstrate that for $\sin^2 2
\theta_{13} \gtrsim 0.04$, two reactor experiments (one air, one matter) with
baselines of at least 1.5 km can constrain any oscillation effect which is
different in air and matter at the level of a few per cent. Furthermore, we
find that using the same experiment while physically moving the material
between source and detector improves systematics.
| [
{
"created": "Mon, 14 Nov 2005 21:02:12 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Schwetz",
"Thomas",
""
],
[
"Winter",
"Walter",
""
]
] | We propose that reactor experiments could be used to constrain the environment dependence of neutrino mass and mixing parameters, which could be induced due to an acceleron coupling to matter fields. There are several short-baseline reactor experiment projects with different fractions of air and earth matter along the neutrino path. Moreover, the short baselines, in principle, allow the physical change of the material between source and detector. Hence, such experiments offer the possibility for a direct comparison of oscillations in air and matter. We demonstrate that for $\sin^2 2 \theta_{13} \gtrsim 0.04$, two reactor experiments (one air, one matter) with baselines of at least 1.5 km can constrain any oscillation effect which is different in air and matter at the level of a few per cent. Furthermore, we find that using the same experiment while physically moving the material between source and detector improves systematics. |
hep-ph/9811348 | Philip G. Ratcliffe | Philip G. Ratcliffe | Theory of Spin Effects in Hard Hadronic Reactions | 18 pages, 7 figures in eps files, packages used: autobf.sty,
axodraw.sty | null | null | EPTCO-98-004 | hep-ph | null | I discuss the present situation with regard to a variety of theoretical
topics in hadronic spin physics: (a) global analysis of the g1
data---positivity at leading and next-to-leading order, renormalisation-scheme
dependence, parametrisation, and hyperon beta-decays; (b) items from the realm
of transverse spin---twist-three effects, single-spin asymmetries, and
transversity; and finally (c) recent developments in understanding the Q^2
evolution of orbital angular momentum.
| [
{
"created": "Mon, 16 Nov 1998 18:04:22 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Ratcliffe",
"Philip G.",
""
]
] | I discuss the present situation with regard to a variety of theoretical topics in hadronic spin physics: (a) global analysis of the g1 data---positivity at leading and next-to-leading order, renormalisation-scheme dependence, parametrisation, and hyperon beta-decays; (b) items from the realm of transverse spin---twist-three effects, single-spin asymmetries, and transversity; and finally (c) recent developments in understanding the Q^2 evolution of orbital angular momentum. |
1510.03714 | Elena Ginina | E. Ginina, A. Bartl, H. Eberl, K. Hidaka, W. Majerotto | Quark-flavour violation in $h^0 \to b \bar{b}$ in the MSSM at one-loop
level | Contribution to the proceedings of EPS-HEP 2015 conference, Vienna | PoS(EPS-HEP2015)146 | null | HEPHY-PUB 961/15, UWThPh-2015-26 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We compute the width of the decay $h^0$ (125 GeV) $\to b \bar{b}$ at
next-to-leading order in the general MSSM with quark-flavour violation (QFV).
We study the effect of mixing between the second and the third generation of
squarks, taking into account the constraints on QFV from B-meson data. We
discuss the renormalisation of the process as well as the resummation of the
bottom Yukawa coupling at large $\tan \beta$. We show numerical results on the
decay width $\Gamma(h^0 \to b \bar{b})$ as a function of the involved QFV
parameters and compare them with the corresponding width in the Standard Model.
| [
{
"created": "Tue, 13 Oct 2015 14:47:22 GMT",
"version": "v1"
}
] | 2015-10-14 | [
[
"Ginina",
"E.",
""
],
[
"Bartl",
"A.",
""
],
[
"Eberl",
"H.",
""
],
[
"Hidaka",
"K.",
""
],
[
"Majerotto",
"W.",
""
]
] | We compute the width of the decay $h^0$ (125 GeV) $\to b \bar{b}$ at next-to-leading order in the general MSSM with quark-flavour violation (QFV). We study the effect of mixing between the second and the third generation of squarks, taking into account the constraints on QFV from B-meson data. We discuss the renormalisation of the process as well as the resummation of the bottom Yukawa coupling at large $\tan \beta$. We show numerical results on the decay width $\Gamma(h^0 \to b \bar{b})$ as a function of the involved QFV parameters and compare them with the corresponding width in the Standard Model. |
hep-ph/0005088 | Nikolai Kochelev | N.I.Kochelev, T.Morii, B.L.Reznik, and A.V.Vinnikov | The role of secondary Reggeons in central meson production | 7 pages, Latex, 5 figures | Eur.Phys.J. A8 (2000) 405-408 | 10.1007/s100500070094 | null | hep-ph | null | We estimate the contribution of f_2 trajectory exchange to the central \eta
and \eta^\prime production. It is shown that secondary Reggeons may give a
large contribution to processes of double diffractive meson production at high
energy.
| [
{
"created": "Wed, 10 May 2000 08:12:47 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Jun 2000 20:56:00 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Kochelev",
"N. I.",
""
],
[
"Morii",
"T.",
""
],
[
"Reznik",
"B. L.",
""
],
[
"Vinnikov",
"A. V.",
""
]
] | We estimate the contribution of f_2 trajectory exchange to the central \eta and \eta^\prime production. It is shown that secondary Reggeons may give a large contribution to processes of double diffractive meson production at high energy. |
2305.06100 | Bai-Song Xie | Orkash Amat, Li-Na Hu, Mamat Ali Bake, Melike Mohamedsedik and B. S.
Xie | Effect of spatially oscillating field on Schwinger pair production | 20 pages, 5 figures | null | null | null | hep-ph quant-ph | http://creativecommons.org/licenses/by/4.0/ | Effect of spatially oscillating fields on the electron-positron pair
production is studied numerically and analytically when the work done by the
electric field over its spatial extent is smaller than twice the electron mass.
Under large spatial scale, we further explain the characteristics of the
position and momentum distribution via tunneling time, tunneling distance and
energy gap between the positive and negative energy bands in the Dirac vacuum.
Our results show that the maximum reduced particle number is about five times
by comparing to maximum number for non-oscillating field. Moreover, the pair
production results via Dirac-Heisenberg-Wigner formalism can be also calculated
by using local density approximation and analytical approximation method when
spatial oscillating cycle number is large. Moreover, in case of large spatial
scale field, the position distribution of created particles could be
interpreted by the tunneling time.
| [
{
"created": "Wed, 10 May 2023 12:41:43 GMT",
"version": "v1"
}
] | 2023-05-11 | [
[
"Amat",
"Orkash",
""
],
[
"Hu",
"Li-Na",
""
],
[
"Bake",
"Mamat Ali",
""
],
[
"Mohamedsedik",
"Melike",
""
],
[
"Xie",
"B. S.",
""
]
] | Effect of spatially oscillating fields on the electron-positron pair production is studied numerically and analytically when the work done by the electric field over its spatial extent is smaller than twice the electron mass. Under large spatial scale, we further explain the characteristics of the position and momentum distribution via tunneling time, tunneling distance and energy gap between the positive and negative energy bands in the Dirac vacuum. Our results show that the maximum reduced particle number is about five times by comparing to maximum number for non-oscillating field. Moreover, the pair production results via Dirac-Heisenberg-Wigner formalism can be also calculated by using local density approximation and analytical approximation method when spatial oscillating cycle number is large. Moreover, in case of large spatial scale field, the position distribution of created particles could be interpreted by the tunneling time. |
1207.4484 | Moritz McGarrie | Moritz McGarrie | General Resonance Mediation | 36 pages, 2 figures. A sum rule added | JHEP 1302 (2013) 093 | 10.1007/JHEP03(2013)093 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We extend the framework of general gauge mediation to cases where the
mediating fields have a nontrivial spectral function, as might arise from
strong dynamics. We demonstrate through examples that this setup describes a
broad class of possible models of gauge mediated supersymmetry breaking. A main
emphasis is to give general formulas for cross sections for
$\sigma(visible\rightarrow hidden)$ in these resonance models. We will also
give formulas for soft masses, A-terms and demonstrate the framework with a
holographic setup.
| [
{
"created": "Wed, 18 Jul 2012 20:00:04 GMT",
"version": "v1"
},
{
"created": "Mon, 30 Jul 2012 13:26:42 GMT",
"version": "v2"
},
{
"created": "Mon, 25 Mar 2013 16:27:08 GMT",
"version": "v3"
}
] | 2013-03-26 | [
[
"McGarrie",
"Moritz",
""
]
] | We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for $\sigma(visible\rightarrow hidden)$ in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup. |
2106.08168 | Huichao Song | Meng Zhou, Fei Gao, Jingyi Chao, Yu-Xin Liu, Huichao Song | Application of radial basis functions neutral networks in spectral
functions | 10 pages, 7 figures | null | 10.1103/PhysRevD.104.076011 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The reconstruction of spectral function from correlation function in
Euclidean space is a challenging task. In this paper, we employ the Machine
Learning techniques in terms of the radial basis functions networks to
reconstruct the spectral function from a finite number of correlation data. To
test our method, we first generate one type of correlation data using a mock
spectral function by mixing several Breit-Wigner propagators. We found that
compared with other traditional methods, TSVD, Tikhonov, and MEM, our approach
gives a continuous and unified reconstruction for both positive definite and
negative spectral function, which is especially useful for studying the QCD
phase transition. Moreover, our approach has considerably better performance in
the low frequency region. This has advantages for the extraction of transport
coefficients which are related to the zero frequency limit of the spectral
function. With the mock data generated through a model spectral function of
stress energy tensor, we find our method gives a precise and stable extraction
of the transport coefficients.
| [
{
"created": "Tue, 15 Jun 2021 14:10:24 GMT",
"version": "v1"
}
] | 2021-10-27 | [
[
"Zhou",
"Meng",
""
],
[
"Gao",
"Fei",
""
],
[
"Chao",
"Jingyi",
""
],
[
"Liu",
"Yu-Xin",
""
],
[
"Song",
"Huichao",
""
]
] | The reconstruction of spectral function from correlation function in Euclidean space is a challenging task. In this paper, we employ the Machine Learning techniques in terms of the radial basis functions networks to reconstruct the spectral function from a finite number of correlation data. To test our method, we first generate one type of correlation data using a mock spectral function by mixing several Breit-Wigner propagators. We found that compared with other traditional methods, TSVD, Tikhonov, and MEM, our approach gives a continuous and unified reconstruction for both positive definite and negative spectral function, which is especially useful for studying the QCD phase transition. Moreover, our approach has considerably better performance in the low frequency region. This has advantages for the extraction of transport coefficients which are related to the zero frequency limit of the spectral function. With the mock data generated through a model spectral function of stress energy tensor, we find our method gives a precise and stable extraction of the transport coefficients. |
hep-ph/9911289 | Anne Ruth Billups | A.H. Mueller | Small-x Physics, High Parton Densities and Parton Saturation in QCD | 33 pages 15 figures | null | null | CU-TP-954 | hep-ph | null | Partons are defined as the quanta in a Fock space description of a hadron.
Gluon saturation is described in the Weizs\"{a}cker-Williams approximation for
a large nucleus. The elements of DGLAP and BFKL evolution are given with the
BFKL equation derived in a large-$N_c$ dipole formalism. A more general
discussion of saturation is given in terms of a dipole scattering on a nucleon
or nucleus. Possible evidence for saturation at HERA is discussed.
| [
{
"created": "Tue, 9 Nov 1999 21:53:33 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Mueller",
"A. H.",
""
]
] | Partons are defined as the quanta in a Fock space description of a hadron. Gluon saturation is described in the Weizs\"{a}cker-Williams approximation for a large nucleus. The elements of DGLAP and BFKL evolution are given with the BFKL equation derived in a large-$N_c$ dipole formalism. A more general discussion of saturation is given in terms of a dipole scattering on a nucleon or nucleus. Possible evidence for saturation at HERA is discussed. |
1603.04168 | Jun He | Pei-Liang L\"u, Jun He | Hadronic molecular states from the $K\bar{K}^*$ interaction | 5 pages | null | 10.1140/epja/i2016-16359-7 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work, the $K\bar{K}^*$ interaction is studied in a quasipotential
Bethe-Salpeter equation approach combined with the one-boson-exchange model.
With the help of the hidden-gauge Lagrangian, the exchanges of pseudoscalar
mesons ($\pi$ and $\eta$) and vector mesons ($\rho$, $\omega$ and $\phi$) are
considered to describe the $K\bar{K}^*$ interaction. Besides the direct
vector-meson exchange which can be related to the Weinberg-Tomozawa term,
pseudoscalar-meson exchanges also play important roles in the mechanism of the
$K\bar{K}^*$ interaction. The poles of scattering amplitude are searched to
find the molecular states produced from the $K\bar{K}^*$ interaction. In the
case of quantum number $I^G(J^{PC})=0^+(1^{++})$, a pole is found with a
reasonable cutoff, which can be related to the $f_1(1285)$ in experiment.
Another bound state with $0^-(1^{+-})$ is also produced from the $K\bar{K}^*$
interaction, which can be related to the $h_1(1380)$. In the isovector sector,
the interaction is much weaker and a bound state with $1^+(1^{+})$ relevant to
the $b_1(1235)$ is produced but at a larger cutoff. Our results suggest that in
the hadronic molecular state picture the $f_1(1285)$ and $b_1(1235)$ are the
strange partners of the $X(3872)$ and $Z_c(3900)$, respectively.
| [
{
"created": "Mon, 14 Mar 2016 09:05:30 GMT",
"version": "v1"
},
{
"created": "Sat, 22 Oct 2016 04:13:33 GMT",
"version": "v2"
},
{
"created": "Sat, 10 Dec 2016 12:35:34 GMT",
"version": "v3"
}
] | 2017-02-01 | [
[
"Lü",
"Pei-Liang",
""
],
[
"He",
"Jun",
""
]
] | In this work, the $K\bar{K}^*$ interaction is studied in a quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model. With the help of the hidden-gauge Lagrangian, the exchanges of pseudoscalar mesons ($\pi$ and $\eta$) and vector mesons ($\rho$, $\omega$ and $\phi$) are considered to describe the $K\bar{K}^*$ interaction. Besides the direct vector-meson exchange which can be related to the Weinberg-Tomozawa term, pseudoscalar-meson exchanges also play important roles in the mechanism of the $K\bar{K}^*$ interaction. The poles of scattering amplitude are searched to find the molecular states produced from the $K\bar{K}^*$ interaction. In the case of quantum number $I^G(J^{PC})=0^+(1^{++})$, a pole is found with a reasonable cutoff, which can be related to the $f_1(1285)$ in experiment. Another bound state with $0^-(1^{+-})$ is also produced from the $K\bar{K}^*$ interaction, which can be related to the $h_1(1380)$. In the isovector sector, the interaction is much weaker and a bound state with $1^+(1^{+})$ relevant to the $b_1(1235)$ is produced but at a larger cutoff. Our results suggest that in the hadronic molecular state picture the $f_1(1285)$ and $b_1(1235)$ are the strange partners of the $X(3872)$ and $Z_c(3900)$, respectively. |
1507.03908 | Enrico Bothmann | Enrico Bothmann, Marek Sch\"onherr, Steffen Schumann | Fast evaluation of theoretical uncertainties with Sherpa and MCgrid | 8 pages, 3 figures, XXIII International Workshop on Deep-Inelastic
Scattering | null | null | ZU-TH 21/15, MCnet-15-18 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The determination of theoretical error estimates and PDF/$\alpha_S$-fits
require fast evaluations of differential cross sections for varied QCD input
parameters. These include PDFs, the strong coupling constant $\alpha_S$ and the
renormalisation and factorisation scales. Beyond leading order QCD, a full
dedicated calculation for each set of parameters is often too time-consuming,
certainly when performing PDF-fits. We report on two methods to overcome this
issue for any QCD NLO calculation: The novel event-reweighting feature in
Sherpa and the automated generation of interpolation grids using the recently
introduced MCgrid interface. For MCgrid we present the newly added support for
fastNLO tables and highlight some future developments.
| [
{
"created": "Tue, 14 Jul 2015 16:13:24 GMT",
"version": "v1"
}
] | 2015-07-16 | [
[
"Bothmann",
"Enrico",
""
],
[
"Schönherr",
"Marek",
""
],
[
"Schumann",
"Steffen",
""
]
] | The determination of theoretical error estimates and PDF/$\alpha_S$-fits require fast evaluations of differential cross sections for varied QCD input parameters. These include PDFs, the strong coupling constant $\alpha_S$ and the renormalisation and factorisation scales. Beyond leading order QCD, a full dedicated calculation for each set of parameters is often too time-consuming, certainly when performing PDF-fits. We report on two methods to overcome this issue for any QCD NLO calculation: The novel event-reweighting feature in Sherpa and the automated generation of interpolation grids using the recently introduced MCgrid interface. For MCgrid we present the newly added support for fastNLO tables and highlight some future developments. |
hep-ph/9710289 | Ken Kiers | Ken Kiers and Nathan Weiss | Neutrino oscillations in a model with a source and detector | 30 pages, 6 figures, Latex | Phys.Rev.D57:3091-3105,1998 | 10.1103/PhysRevD.57.3091 | null | hep-ph | null | We study the oscillations of neutrinos in a model in which the neutrino is
coupled to a localized, idealized source and detector. By varying the spatial
and temporal resolution of the source and detector we are able to model the
full range of source and detector types ranging from coherent to incoherent. We
find that this approach is useful in understanding the interface between the
Quantum Mechanical nature of neutrino oscillations on the one hand and the
production and detection systems on the other hand. This method can easily be
extended to study the oscillations of other particles such as the neutral K and
B mesons. We find that this approach gives a reliable way to treat the various
ambiguities which arise when one examines the oscillations from a wave packet
point of view. We demonstrate that the conventional oscillation formula is
correct in the relativistic limit and that several recent claims of an extra
factor of 2 in the oscillation length are incorrect. We also demonstrate
explicitly that the oscillations of neutrinos which have separated spatially
may be "revived" by a long coherent measurement.
| [
{
"created": "Wed, 8 Oct 1997 16:37:24 GMT",
"version": "v1"
}
] | 2014-11-17 | [
[
"Kiers",
"Ken",
""
],
[
"Weiss",
"Nathan",
""
]
] | We study the oscillations of neutrinos in a model in which the neutrino is coupled to a localized, idealized source and detector. By varying the spatial and temporal resolution of the source and detector we are able to model the full range of source and detector types ranging from coherent to incoherent. We find that this approach is useful in understanding the interface between the Quantum Mechanical nature of neutrino oscillations on the one hand and the production and detection systems on the other hand. This method can easily be extended to study the oscillations of other particles such as the neutral K and B mesons. We find that this approach gives a reliable way to treat the various ambiguities which arise when one examines the oscillations from a wave packet point of view. We demonstrate that the conventional oscillation formula is correct in the relativistic limit and that several recent claims of an extra factor of 2 in the oscillation length are incorrect. We also demonstrate explicitly that the oscillations of neutrinos which have separated spatially may be "revived" by a long coherent measurement. |
0811.2998 | Gabriela Barenboim | Gabriela Barenboim (U. Valencia and IFIC) | Inflation might be caused by the right | 15 pages, 4 figures | JHEP 0903:102,2009 | 10.1088/1126-6708/2009/03/102 | null | hep-ph astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that the scalar field that drives inflation can have a dynamical
origin, being a strongly coupled right handed neutrino condensate. The
resulting model is phenomenologically tightly constrained, and can be
experimentally (dis)probed in the near future. The mass of the right handed
neutrino obtained this way (a crucial ingredient to obtain the right light
neutrino spectrum within the see-saw mechanism in a complete three generation
framework) is related to that of the inflaton and both completely determine the
inflation features that can be tested by current and planned experiments.
| [
{
"created": "Tue, 18 Nov 2008 21:01:44 GMT",
"version": "v1"
}
] | 2009-03-31 | [
[
"Barenboim",
"Gabriela",
"",
"U. Valencia and IFIC"
]
] | We show that the scalar field that drives inflation can have a dynamical origin, being a strongly coupled right handed neutrino condensate. The resulting model is phenomenologically tightly constrained, and can be experimentally (dis)probed in the near future. The mass of the right handed neutrino obtained this way (a crucial ingredient to obtain the right light neutrino spectrum within the see-saw mechanism in a complete three generation framework) is related to that of the inflaton and both completely determine the inflation features that can be tested by current and planned experiments. |
1109.6641 | Jarah Evslin | Emilio Ciuffoli, Jarah Evslin, Jie Liu and Xinmin Zhang | Neutrino Dispersion Relations from a Dark Energy Model | 19 pages, no figures, v2 detailed treatment of MSW, motivation from
OPERA anomaly deemphasized | ISRN High Energy Physics 2013 (2013) 497071 | 10.1155/2013/497071 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a model in which the neutrino is kinetically coupled to a scalar
field and study its implications for environmentally dependent neutrino
velocities. Following the usual effective field theory logic, this coupling is
expected to arise in neutrino dark energy models. It leads to a Lorentz
violation in the neutrino sector. The coupling of the scalar field to the
stress tensor of the Earth yields terrestrial neutrino dispersion relations
distinct from those in interstellar space.
| [
{
"created": "Thu, 29 Sep 2011 19:51:20 GMT",
"version": "v1"
},
{
"created": "Mon, 24 Oct 2011 07:57:24 GMT",
"version": "v2"
},
{
"created": "Mon, 26 Nov 2012 15:16:22 GMT",
"version": "v3"
}
] | 2013-01-22 | [
[
"Ciuffoli",
"Emilio",
""
],
[
"Evslin",
"Jarah",
""
],
[
"Liu",
"Jie",
""
],
[
"Zhang",
"Xinmin",
""
]
] | We consider a model in which the neutrino is kinetically coupled to a scalar field and study its implications for environmentally dependent neutrino velocities. Following the usual effective field theory logic, this coupling is expected to arise in neutrino dark energy models. It leads to a Lorentz violation in the neutrino sector. The coupling of the scalar field to the stress tensor of the Earth yields terrestrial neutrino dispersion relations distinct from those in interstellar space. |
1105.4454 | Pasquini Barbara | B. Pasquini (U. Pavia & INFN, Pavia, Italy), D. Drechsel and M.
Vanderhaeghen (Mainz U., Inst. Kernphys.) | Nucleon Polarizabilities: Theory | 17 pages, 7 figures, 1 Table; proceedings of "Many-Body Structure of
Strongly Interacting Systems", Mainz, Germany, Feb. 23-25 2011 (to appear in
EPJ Special Topics) | Eur.Phys.J.ST 198 (2011) 269-285 | 10.1140/epjst/e2011-01494-y | null | hep-ph hep-lat nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review recent developments in the theoretical investigation of the nucleon
polarizabilities. We first report on the static polarizabilities as measured in
real Compton scattering, comparing and interpreting the results from various
theoretical approaches. In a second step, we extend the discussion to the
generalized polarizabilities which can be accessed in virtual Compton
scattering, showing how the information encoded in these quantities can provide
a spatial interpretation of the induced polarization densities in the nucleon.
| [
{
"created": "Mon, 23 May 2011 10:01:03 GMT",
"version": "v1"
}
] | 2012-01-17 | [
[
"Pasquini",
"B.",
"",
"U. Pavia & INFN, Pavia, Italy"
],
[
"Drechsel",
"D.",
"",
"Mainz U., Inst. Kernphys."
],
[
"Vanderhaeghen",
"M.",
"",
"Mainz U., Inst. Kernphys."
]
] | We review recent developments in the theoretical investigation of the nucleon polarizabilities. We first report on the static polarizabilities as measured in real Compton scattering, comparing and interpreting the results from various theoretical approaches. In a second step, we extend the discussion to the generalized polarizabilities which can be accessed in virtual Compton scattering, showing how the information encoded in these quantities can provide a spatial interpretation of the induced polarization densities in the nucleon. |
hep-ph/0311015 | Elvio Di Salvo | E. Di Salvo | A rigorous bound on quark distributions in the nucleon | Talk given at the QCD03 Conference, Montpellier, 2-9 July 2003 | Nucl.Phys.Proc.Suppl.133:73-76,2004 | 10.1016/j.nuclphysbps.2004.04.140 | null | hep-ph | null | I deduce an inequality between the helicity and the transversity distribution
of a quark in a nucleon, at small energy scales. Then I establish, thanks to
the positivity constraint, a rigorous bound on longitudinally polarized valence
quark densities, which finds nontrivial applications to d-quarks. This, in
turn, implies a bound for the distributions of the longitudinally polarized
sea, which is probably not SU(3)-symmetric. Some model predictions and
parametrizations of quark distributions are examined in the light of these
results.
| [
{
"created": "Mon, 3 Nov 2003 09:37:04 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Di Salvo",
"E.",
""
]
] | I deduce an inequality between the helicity and the transversity distribution of a quark in a nucleon, at small energy scales. Then I establish, thanks to the positivity constraint, a rigorous bound on longitudinally polarized valence quark densities, which finds nontrivial applications to d-quarks. This, in turn, implies a bound for the distributions of the longitudinally polarized sea, which is probably not SU(3)-symmetric. Some model predictions and parametrizations of quark distributions are examined in the light of these results. |
hep-ph/9611348 | Phil Ratcliffe | Philip G. Ratcliffe | Symposium Summary | Summary Talk, presented at SPIN '96 - The 12th. International
Symposium on High-Energy Spin Physics (Amsterdam, Sept. 1996). LaTeX, 10
pages, 1 figure (self inserting with epsfig) | null | null | EPTCO-96-001 | hep-ph | null | The plenary presentations of the conference are summarised, highlighting some
aspects that were of particular interest and attempting to link a few of the
topics covered. Particular emphasis is placed on the problem of deep-inelastic
scattering and questions still to be answered with regard to the distribution
functions, strange-quark and gluon contributions, and the possible r\^ole of
orbital angular momentum. Passing reference is also made to some of the
parallel session presentations.
| [
{
"created": "Mon, 18 Nov 1996 12:03:38 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Ratcliffe",
"Philip G.",
""
]
] | The plenary presentations of the conference are summarised, highlighting some aspects that were of particular interest and attempting to link a few of the topics covered. Particular emphasis is placed on the problem of deep-inelastic scattering and questions still to be answered with regard to the distribution functions, strange-quark and gluon contributions, and the possible r\^ole of orbital angular momentum. Passing reference is also made to some of the parallel session presentations. |
hep-ph/0302137 | Viktor Nikonov | V.V. Anisovich, L.G Dakhno, V.A. Nikonov | D^+_s -> pi^+ pi^+ pi^- decay: the 1^3P_0 s anti-s component in
scalar-isoscalar mesons | 17 pages, 4 figures, epsfig | Phys.Atom.Nucl. 67 (2004) 1571-1579; Yad.Fiz. 67 (2004) 1593-1601 | 10.1134/1.1788047 | null | hep-ph | null | On the basis of data on the decay D^+_s -> pi^+ pi^+ pi^-, which goes
dominantly via the transition D_s -> pi^+ s anti-s, we evaluate the 1^3P_0 s
anti-s components in the scalar-isoscalar resonances f0(980), f0(1300),
f0(1500) and broad state f0(1200-1600)$. The data point to a large s anti-s
component in the f0(980): 40% < s anti-s < 70%. Nearly 30% of the 1^3P_0 s
anti-s component flows to the mass region 1300-1500 MeV being shared by
f0(1300), f0(1500) and broad state f0(1200-1600): the interference of these
states results in a peak near 1400 MeV with the width around 200 MeV.
| [
{
"created": "Mon, 17 Feb 2003 11:27:26 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"Anisovich",
"V. V.",
""
],
[
"Dakhno",
"L. G",
""
],
[
"Nikonov",
"V. A.",
""
]
] | On the basis of data on the decay D^+_s -> pi^+ pi^+ pi^-, which goes dominantly via the transition D_s -> pi^+ s anti-s, we evaluate the 1^3P_0 s anti-s components in the scalar-isoscalar resonances f0(980), f0(1300), f0(1500) and broad state f0(1200-1600)$. The data point to a large s anti-s component in the f0(980): 40% < s anti-s < 70%. Nearly 30% of the 1^3P_0 s anti-s component flows to the mass region 1300-1500 MeV being shared by f0(1300), f0(1500) and broad state f0(1200-1600): the interference of these states results in a peak near 1400 MeV with the width around 200 MeV. |
1605.03625 | Doug McKay | K. S. Babu, Douglas W. McKay, Irina Mocioiu, Sandip Pakvasa | Light Sterile Neutrinos, Lepton Number Violating Interactions and the
LSND Anomaly | 21 pages, 8 figures, text and references added conclusions unchanged;
version that appears in Phys, Rev. D | Phys. Rev. D 93, 113019 (2016) | 10.1103/PhysRevD.93.113019 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We develop the consequences of introducing a purely leptonic, lepton number
violating non-standard interaction (NSI) and standard model neutrino mixing
with a fourth, sterile neutrino in the analysis of short-baseline, neutrino
experiments. We focus on the muon decay at rest (DAR) result from the Liquid
Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford
Medium Energy Neutrino Experiment (KARMEN). We make a comprehensive analysis of
lepton number violating, NSI effective operators and find nine that affect muon
decay relevant to LSND results. Two of these preserve the standard model (SM)
value 3/4 for the Michel rho and delta parameters and, overall, show favorable
agreement with precision data and the electron anti-neutrino signal from LSND
data. We display theoretical models that lead to these two effective operators.
In the model we choose to apply to DAR data, both electron anti-neutrino
appearance from muon anti-neutrino oscillation and electron anti-neutrino
survival after production from NSI decay of the positive muon contribute to the
expected signal. This is a unique feature of our scheme. We find a range of
parameters where both experiments can be accommodated consistently with recent
global, sterile neutrino fits to short baseline data. We comment on
implications of the models for new physics searches at colliders and comment on
further implications of the lepton number violating interactions plus sterile
neutrino-standard model neutrino mixing.
| [
{
"created": "Wed, 11 May 2016 21:31:02 GMT",
"version": "v1"
},
{
"created": "Sun, 3 Jul 2016 22:29:03 GMT",
"version": "v2"
}
] | 2016-07-06 | [
[
"Babu",
"K. S.",
""
],
[
"McKay",
"Douglas W.",
""
],
[
"Mocioiu",
"Irina",
""
],
[
"Pakvasa",
"Sandip",
""
]
] | We develop the consequences of introducing a purely leptonic, lepton number violating non-standard interaction (NSI) and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short-baseline, neutrino experiments. We focus on the muon decay at rest (DAR) result from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford Medium Energy Neutrino Experiment (KARMEN). We make a comprehensive analysis of lepton number violating, NSI effective operators and find nine that affect muon decay relevant to LSND results. Two of these preserve the standard model (SM) value 3/4 for the Michel rho and delta parameters and, overall, show favorable agreement with precision data and the electron anti-neutrino signal from LSND data. We display theoretical models that lead to these two effective operators. In the model we choose to apply to DAR data, both electron anti-neutrino appearance from muon anti-neutrino oscillation and electron anti-neutrino survival after production from NSI decay of the positive muon contribute to the expected signal. This is a unique feature of our scheme. We find a range of parameters where both experiments can be accommodated consistently with recent global, sterile neutrino fits to short baseline data. We comment on implications of the models for new physics searches at colliders and comment on further implications of the lepton number violating interactions plus sterile neutrino-standard model neutrino mixing. |
0710.4476 | Harri Niemi | K.J. Eskola, H. Niemi and P.V. Ruuskanen | Dynamical freeze-out condition in ultrarelativistic heavy ion collisions | 7 pages, 9 figures | Phys.Rev.C77:044907,2008 | 10.1103/PhysRevC.77.044907 | null | hep-ph nucl-th | null | We determine the decoupling surfaces for the hydrodynamic description of
heavy ion collisions at RHIC and LHC by comparing the local hydrodynamic
expansion rate with the microscopic pion-pion scattering rate. The pion $p_T$
spectra for nuclear collisions at RHIC and LHC are computed by applying the
Cooper-Frye procedure on the dynamical-decoupling surfaces, and compared with
those obtained from the constant-temperature freeze-out surfaces. Comparison
with RHIC data shows that the system indeed decouples when the expansion rate
becomes comparable with the pion scattering rate. The dynamical decoupling
based on the rates comparison also suggests that the effective decoupling
temperature in central heavy ion collisions remains practically unchanged from
RHIC to LHC.
| [
{
"created": "Wed, 24 Oct 2007 14:10:28 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Eskola",
"K. J.",
""
],
[
"Niemi",
"H.",
""
],
[
"Ruuskanen",
"P. V.",
""
]
] | We determine the decoupling surfaces for the hydrodynamic description of heavy ion collisions at RHIC and LHC by comparing the local hydrodynamic expansion rate with the microscopic pion-pion scattering rate. The pion $p_T$ spectra for nuclear collisions at RHIC and LHC are computed by applying the Cooper-Frye procedure on the dynamical-decoupling surfaces, and compared with those obtained from the constant-temperature freeze-out surfaces. Comparison with RHIC data shows that the system indeed decouples when the expansion rate becomes comparable with the pion scattering rate. The dynamical decoupling based on the rates comparison also suggests that the effective decoupling temperature in central heavy ion collisions remains practically unchanged from RHIC to LHC. |
1801.03772 | Max Zoller | Federico Buccioni, Stefano Pozzorini, Max Zoller | A new method for one-loop amplitude generation and reduction in
OpenLoops | Contribution to the proceedings of the 13th International Symposium
on Radiative Corrections (Applications of Quantum Field Theory to
Phenomenology), 25-29 September, 2017, St. Gilgen, Austria | null | null | ZU-TH 02/18 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe a new method for the automated construction of one-loop
amplitudes based on the open-loop algorithm, where various operations are
performed on-the-fly while constructing the integrand. In particular, an
on-the-fly reduction interleaved with the construction steps of the amplitude
keeps the maximum tensor rank in the loop momentum at two throughout the
algorithm, thus drastically reducing the complexity of the calculation. The
full reduction to scalar integrals is unified with the amplitude construction
in a single recursion within the OpenLoops framework. This approach strongly
exploits the factorisation of one-loop integrands in a product of loop
segments. The on-the-fly approach, which is also applied to helicity summation
and the merging of different diagrams, increases the speed of the original
open-loop algorithm in a very significant way. A remarkably high level of
numerical stability is achieved by exploiting freedoms in reduction identities
and through simple expansions in rank-two Gram determinants. These features are
particularly attractive for NLO multi-leg and NNLO real-virtual calculations.
The new algorithm will be made public in a forthcoming release of the OpenLoops
program.
| [
{
"created": "Thu, 11 Jan 2018 14:22:28 GMT",
"version": "v1"
}
] | 2018-01-12 | [
[
"Buccioni",
"Federico",
""
],
[
"Pozzorini",
"Stefano",
""
],
[
"Zoller",
"Max",
""
]
] | We describe a new method for the automated construction of one-loop amplitudes based on the open-loop algorithm, where various operations are performed on-the-fly while constructing the integrand. In particular, an on-the-fly reduction interleaved with the construction steps of the amplitude keeps the maximum tensor rank in the loop momentum at two throughout the algorithm, thus drastically reducing the complexity of the calculation. The full reduction to scalar integrals is unified with the amplitude construction in a single recursion within the OpenLoops framework. This approach strongly exploits the factorisation of one-loop integrands in a product of loop segments. The on-the-fly approach, which is also applied to helicity summation and the merging of different diagrams, increases the speed of the original open-loop algorithm in a very significant way. A remarkably high level of numerical stability is achieved by exploiting freedoms in reduction identities and through simple expansions in rank-two Gram determinants. These features are particularly attractive for NLO multi-leg and NNLO real-virtual calculations. The new algorithm will be made public in a forthcoming release of the OpenLoops program. |
1601.01828 | Debasish Borah | Debasish Borah, Sudhanwa Patra and Shibananda Sahoo | Subdominant Left-Right Scalar Dark Matter as Origin of the 750 GeV
Di-photon Excess at LHC | 32 pages, 12 figures, to appear in IJMPA | null | 10.1142/S0217751X16500974 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the possibility of explaining the recently reported 750 GeV
di-photon excess at LHC within the framework of a left-right symmetric model.
The 750 GeV neutral scalar in the model is dominantly an admixture of neutral
components of scalar bidoublets with a tiny fraction of neutral scalar triplet.
Incorporating $SU(2)$ septuplet scalar pairs into the model, we enhance the
partial decay width of the 750 GeV neutral scalar into di-photons through
charged septuplet components in loop while keeping the neutral septuplet
components as subdominant dark matter candidates. The model also predicts the
decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or
ruled out by future LHC data. The requirement of producing the correct
di-photon signal automatically keeps the septuplet dark matter abundance
subdominant in agreement with bounds from direct and indirect detection
experiments. We then briefly discuss different possibilities to account for the
remaining dark matter component of the Universe in terms of other particle
candidates whose stability arise either due to remnant discrete symmetry after
spontaneous breaking of $U(1)_{B-L}$ or due to high $SU(2)$-dimension
forbidding their decay into lighter particles.
| [
{
"created": "Fri, 8 Jan 2016 10:55:48 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Jun 2016 08:45:26 GMT",
"version": "v2"
}
] | 2016-07-20 | [
[
"Borah",
"Debasish",
""
],
[
"Patra",
"Sudhanwa",
""
],
[
"Sahoo",
"Shibananda",
""
]
] | We study the possibility of explaining the recently reported 750 GeV di-photon excess at LHC within the framework of a left-right symmetric model. The 750 GeV neutral scalar in the model is dominantly an admixture of neutral components of scalar bidoublets with a tiny fraction of neutral scalar triplet. Incorporating $SU(2)$ septuplet scalar pairs into the model, we enhance the partial decay width of the 750 GeV neutral scalar into di-photons through charged septuplet components in loop while keeping the neutral septuplet components as subdominant dark matter candidates. The model also predicts the decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or ruled out by future LHC data. The requirement of producing the correct di-photon signal automatically keeps the septuplet dark matter abundance subdominant in agreement with bounds from direct and indirect detection experiments. We then briefly discuss different possibilities to account for the remaining dark matter component of the Universe in terms of other particle candidates whose stability arise either due to remnant discrete symmetry after spontaneous breaking of $U(1)_{B-L}$ or due to high $SU(2)$-dimension forbidding their decay into lighter particles. |
0805.3358 | Christian Sturm | Christian Sturm | Moments of Heavy Quark Current Correlators at Four-Loop Order in
Perturbative QCD | 12 pages, 1 figure | JHEP 0809:075,2008 | 10.1088/1126-6708/2008/09/075 | BNL-HET-08/12 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present the result for the first moment of the scalar and axial-vector
current correlator in third order of the strong coupling constant alpha_s and
give the details of a recent evaluation of the pseudo-scalar correlator. The
results can be used to reduce the theoretical uncertainty due to higher order
corrections for the determination of fundamental parameters of QCD in the
context of lattice calculations.
| [
{
"created": "Wed, 21 May 2008 23:33:23 GMT",
"version": "v1"
}
] | 2009-01-06 | [
[
"Sturm",
"Christian",
""
]
] | We present the result for the first moment of the scalar and axial-vector current correlator in third order of the strong coupling constant alpha_s and give the details of a recent evaluation of the pseudo-scalar correlator. The results can be used to reduce the theoretical uncertainty due to higher order corrections for the determination of fundamental parameters of QCD in the context of lattice calculations. |
hep-ph/0406274 | Jusak Tandean | Jusak Tandean | Probing CP Violation in Omega->Lambda K->p pi K Decay | 19 pages, 4 figures | Phys.Rev. D70 (2004) 076005 | 10.1103/PhysRevD.70.076005 | SMU-HEP-04-06 | hep-ph hep-ex | null | The sum of the CP-violating asymmetries A_Omega and A_Lambda in the decay
sequence Omega->Lambda K, Lambda->p pi is presently being measured by the E871
experiment. We evaluate contributions to A_Omega from the standard model and
from possible new physics, and find them to be smaller than the corresponding
contributions to A_Lambda, although not negligibly so. We also show that the
partial-rate asymmetry in Omega->Lambda K is nonvanishing due to final-state
interactions. Taking into account constraints from kaon data, we discuss how
the upcoming result of E871 and future measurements may probe the various
contributions to the observables.
| [
{
"created": "Thu, 24 Jun 2004 19:32:12 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Tandean",
"Jusak",
""
]
] | The sum of the CP-violating asymmetries A_Omega and A_Lambda in the decay sequence Omega->Lambda K, Lambda->p pi is presently being measured by the E871 experiment. We evaluate contributions to A_Omega from the standard model and from possible new physics, and find them to be smaller than the corresponding contributions to A_Lambda, although not negligibly so. We also show that the partial-rate asymmetry in Omega->Lambda K is nonvanishing due to final-state interactions. Taking into account constraints from kaon data, we discuss how the upcoming result of E871 and future measurements may probe the various contributions to the observables. |
1911.11771 | WanLing Chang | Jiao Jiao Song, and Wan Ling Chang | Spin Density Matrix For Spin-3/2 Particles | 11 pages | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The description of particles with spin can be attained by using a spin
density matrix in high energy reaction. In this paper we present a
parametrization of the spin density matrix for spin -3/2 particles in the
Cartesian form. Comparing the standard form which is given by the spherical
tensor operator with the Cartesian form yields four equations for the spin
polarizations. These four equations can be used to eliminate the dependent spin
polarizations. We also present the probabilistic interpretations of these spin
polarizations by defining the spin operator in the spherical coordinate frame.
These results can be used in the cross section to calculate the hadron
polarizations. To illustrate this, we calculate the inclusive electron-positron
annihilation process in terms of spin polarizations.
| [
{
"created": "Tue, 26 Nov 2019 13:46:58 GMT",
"version": "v1"
},
{
"created": "Sat, 2 May 2020 12:40:31 GMT",
"version": "v2"
}
] | 2020-05-05 | [
[
"Song",
"Jiao Jiao",
""
],
[
"Chang",
"Wan Ling",
""
]
] | The description of particles with spin can be attained by using a spin density matrix in high energy reaction. In this paper we present a parametrization of the spin density matrix for spin -3/2 particles in the Cartesian form. Comparing the standard form which is given by the spherical tensor operator with the Cartesian form yields four equations for the spin polarizations. These four equations can be used to eliminate the dependent spin polarizations. We also present the probabilistic interpretations of these spin polarizations by defining the spin operator in the spherical coordinate frame. These results can be used in the cross section to calculate the hadron polarizations. To illustrate this, we calculate the inclusive electron-positron annihilation process in terms of spin polarizations. |
hep-ph/9901376 | E. R. Berger | E. R. Berger, A. Donnachie, H. G. Dosch, W. Kilian, O. Nachtmann, M.
Rueter | Odderon and photon exchange in electroproduction of pseudoscalar mesons | 20 pages, 7 figures | Eur.Phys.J.C9:491-501,1999 | 10.1007/s100529900067 | HD--THEP--99--3, TAUP--2548--99 | hep-ph | null | We investigate the reaction $e p \to e PS X$ where PS denotes a pseudoscalar
meson $\pi^0, \eta, \eta'$, or $\eta_c$ and X either a proton or resonance or
continuum states into which the proton can go by diffractive excitation. At
high energies photon and odderon exchange contribute to the reaction. The
photon exchange contribution is evaluated exactly using data for the total
virtual photon-proton absorption cross section. The odderon exchange
contribution is calculated in nonperturbative QCD, using functional integral
techniques and the model of the stochastic vacuum. For the proton we assume a
quark-diquark structure as suggested by the small odderon amplitude in $pp$ and
$p \bar{p}$ forward scattering. We show that odderon exchange leads to a much
larger inelastic than elastic PS production cross section. Observation of our
reaction at HERA would establish the soft odderon as an exchange object on an
equal footing with the soft pomeron and would give us valuable insight into
both the nucleon structure and the mechanism of high energy diffractive
scattering.
| [
{
"created": "Thu, 21 Jan 1999 18:51:14 GMT",
"version": "v1"
}
] | 2016-09-06 | [
[
"Berger",
"E. R.",
""
],
[
"Donnachie",
"A.",
""
],
[
"Dosch",
"H. G.",
""
],
[
"Kilian",
"W.",
""
],
[
"Nachtmann",
"O.",
""
],
[
"Rueter",
"M.",
""
]
] | We investigate the reaction $e p \to e PS X$ where PS denotes a pseudoscalar meson $\pi^0, \eta, \eta'$, or $\eta_c$ and X either a proton or resonance or continuum states into which the proton can go by diffractive excitation. At high energies photon and odderon exchange contribute to the reaction. The photon exchange contribution is evaluated exactly using data for the total virtual photon-proton absorption cross section. The odderon exchange contribution is calculated in nonperturbative QCD, using functional integral techniques and the model of the stochastic vacuum. For the proton we assume a quark-diquark structure as suggested by the small odderon amplitude in $pp$ and $p \bar{p}$ forward scattering. We show that odderon exchange leads to a much larger inelastic than elastic PS production cross section. Observation of our reaction at HERA would establish the soft odderon as an exchange object on an equal footing with the soft pomeron and would give us valuable insight into both the nucleon structure and the mechanism of high energy diffractive scattering. |
0809.1302 | Stefano Actis | S. Actis, G. Passarino, C. Sturm, S. Uccirati | Two-Loop Threshold Singularities, Unstable Particles and Complex Masses | LaTeX, 12 pages, 7 figures | Phys.Lett.B669:62-68,2008 | 10.1016/j.physletb.2008.09.028 | PITHA 08/21, SFB/CPP-08-63, TTP08-39 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The effect of threshold singularities induced by unstable particles on
two-loop observables is investigated and it is shown how to cure them working
in the complex-mass scheme. The impact on radiative corrections around
thresholds is thoroughly analyzed and shown to be relevant for two selected LHC
and ILC applications: Higgs production via gluon fusion and decay into two
photons at two loops in the Standard Model. Concerning Higgs production, it is
essential to understand possible sources of large corrections in addition to
the well-known QCD effects. It is shown that NLO electroweak corrections can
incongruently reach a 10 % level around the WW vector-boson threshold without a
complete implementation of the complex-mass scheme in the two-loop calculation.
| [
{
"created": "Mon, 8 Sep 2008 09:42:53 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Actis",
"S.",
""
],
[
"Passarino",
"G.",
""
],
[
"Sturm",
"C.",
""
],
[
"Uccirati",
"S.",
""
]
] | The effect of threshold singularities induced by unstable particles on two-loop observables is investigated and it is shown how to cure them working in the complex-mass scheme. The impact on radiative corrections around thresholds is thoroughly analyzed and shown to be relevant for two selected LHC and ILC applications: Higgs production via gluon fusion and decay into two photons at two loops in the Standard Model. Concerning Higgs production, it is essential to understand possible sources of large corrections in addition to the well-known QCD effects. It is shown that NLO electroweak corrections can incongruently reach a 10 % level around the WW vector-boson threshold without a complete implementation of the complex-mass scheme in the two-loop calculation. |
2009.02723 | Yuming Wang | Yue-Long Shen, Yu-Ming Wang, Yan-Bing Wei | Precision calculations of the double radiative bottom-meson decays in
soft-collinear effective theory | 58 pages, 7 figures | null | 10.1007/JHEP12(2020)169 | null | hep-ph hep-ex hep-lat | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Employing the systematic framework of soft-collinear effective theory (SCET)
we perform an improved calculation of the leading-power contributions to the
double radiative $B_{d, \, s}$-meson decay amplitudes in the heavy quark
expansion. We then construct the QCD factorization formulae for the subleading
power contributions arising from the energetic photon radiation off the
constituent light-flavour quark of the bottom meson at tree level. Furthermore,
we explore the factorization properties of the subleading power correction from
the effective SCET current $J^{(A2)}$ at ${\cal O} (\alpha_s^0)$. The
higher-twist contributions to the $B_{d, \, s} \to \gamma \gamma $ helicity
form factors from the two-particle and three-particle bottom-meson distribution
amplitudes are evaluated up to the twist-six accuracy. In addition, the
subleading power weak-annihilation contributions from both the current-current
and QCD penguin operators are taken into account at the one-loop accuracy. We
proceed to apply the operator-production-expansion-controlled dispersion
relation for estimating the power-suppressed soft contributions to the double
radiative $B_{d, \, s}$-meson decay form factors. Phenomenological explorations
of the radiative $B_{d, \, s} \to \gamma \, \gamma$ decay observables in the
presence of the neutral-meson mixing, including the CP-averaged branching
fractions, the polarization fractions and the time-dependent CP asymmetries,
are carried out subsequently with an emphasis on the numerical impacts of the
newly computed ingredients together with the theory uncertainties from the
shape parameters of the HQET bottom-meson distribution amplitudes.
| [
{
"created": "Sun, 6 Sep 2020 12:48:33 GMT",
"version": "v1"
}
] | 2021-02-03 | [
[
"Shen",
"Yue-Long",
""
],
[
"Wang",
"Yu-Ming",
""
],
[
"Wei",
"Yan-Bing",
""
]
] | Employing the systematic framework of soft-collinear effective theory (SCET) we perform an improved calculation of the leading-power contributions to the double radiative $B_{d, \, s}$-meson decay amplitudes in the heavy quark expansion. We then construct the QCD factorization formulae for the subleading power contributions arising from the energetic photon radiation off the constituent light-flavour quark of the bottom meson at tree level. Furthermore, we explore the factorization properties of the subleading power correction from the effective SCET current $J^{(A2)}$ at ${\cal O} (\alpha_s^0)$. The higher-twist contributions to the $B_{d, \, s} \to \gamma \gamma $ helicity form factors from the two-particle and three-particle bottom-meson distribution amplitudes are evaluated up to the twist-six accuracy. In addition, the subleading power weak-annihilation contributions from both the current-current and QCD penguin operators are taken into account at the one-loop accuracy. We proceed to apply the operator-production-expansion-controlled dispersion relation for estimating the power-suppressed soft contributions to the double radiative $B_{d, \, s}$-meson decay form factors. Phenomenological explorations of the radiative $B_{d, \, s} \to \gamma \, \gamma$ decay observables in the presence of the neutral-meson mixing, including the CP-averaged branching fractions, the polarization fractions and the time-dependent CP asymmetries, are carried out subsequently with an emphasis on the numerical impacts of the newly computed ingredients together with the theory uncertainties from the shape parameters of the HQET bottom-meson distribution amplitudes. |
2407.14673 | Girish Kumar | Girish Kumar, Alexey A. Petrov | Constraints on light dark sector particles from lifetime difference of
heavy neutral mesons | 18 pages, 5 captioned figures, 1 table | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | Heavy meson decays with missing energy in the final state offer interesting
avenues to search for light invisible new physics such as dark matter (DM). In
this context, we show that such NP interactions also affect lifetime difference
in neutral meson-antimeson mixing. We consider general dimension-six effective
quark interactions involving a pair of DM particles and calculate their
contributions to lifetime difference in beauty and charm meson systems. We use
the latest data on mixing observables to constrain the relevant effective
operators. We find that lifetime differences provide novel and complementary
flavor constraints compared to those obtained from heavy meson decays.
| [
{
"created": "Fri, 19 Jul 2024 21:28:38 GMT",
"version": "v1"
}
] | 2024-07-23 | [
[
"Kumar",
"Girish",
""
],
[
"Petrov",
"Alexey A.",
""
]
] | Heavy meson decays with missing energy in the final state offer interesting avenues to search for light invisible new physics such as dark matter (DM). In this context, we show that such NP interactions also affect lifetime difference in neutral meson-antimeson mixing. We consider general dimension-six effective quark interactions involving a pair of DM particles and calculate their contributions to lifetime difference in beauty and charm meson systems. We use the latest data on mixing observables to constrain the relevant effective operators. We find that lifetime differences provide novel and complementary flavor constraints compared to those obtained from heavy meson decays. |
hep-ph/9712515 | Hitoshi Murayama | Lawrence J. Hall, Takeo Moroi and Hitoshi Murayama (UC Berkeley, LBNL) | Sneutrino Cold Dark Matter With Lepton-Number Violation | 15 pages, 3 figures, uses psfig | Phys.Lett.B424:305-312,1998 | 10.1016/S0370-2693(98)00196-8 | UCB-PTH-97/69, LBNL-41199 | hep-ph astro-ph hep-ex | null | The tau sneutrino is proposed as a candidate for galactic halo dark matter,
and as the cold dark matter (CDM) component of the universe. A
lepton-number-violating sneutrino mass, \tilde{\nu}\tilde{\nu}, splits the tau
sneutrino into two mass eigenstates: \tilde{\nu} \rightarrow \tilde{\nu}_\pm.
The absence of a Z \tilde{\nu}_- \tilde{\nu}_- coupling implies that the
lighter mass eignestate, \tilde{\nu}_-, does not annihilate via the s-channel
Z-exchange to a low cosmological abundance, and furthermore, halo sneutrinos do
not scatter excessively in Ge detectors. For the majority of the relevant
parameter space, the event rate in Ge detectors is \geq 10^{-2} events/kg/day.
The lepton number violation required for sneutrino CDM implies that the tau
neutrino mass is m_{\nu_\tau} \gtrsim 5 MeV, large enough to be excluded by B
factory experiments. Events of the form l^+ l^- \not E or jj \not E , with low
m_{ll} or m_{jj}, may be observed at LEP2. A seesaw mechanism is investigated
as the origin for the lepton number violation, and several other cosmological
and particle physics consequences of sneutrino CDM are discussed.
| [
{
"created": "Wed, 24 Dec 1997 00:55:54 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Hall",
"Lawrence J.",
"",
"UC Berkeley, LBNL"
],
[
"Moroi",
"Takeo",
"",
"UC Berkeley, LBNL"
],
[
"Murayama",
"Hitoshi",
"",
"UC Berkeley, LBNL"
]
] | The tau sneutrino is proposed as a candidate for galactic halo dark matter, and as the cold dark matter (CDM) component of the universe. A lepton-number-violating sneutrino mass, \tilde{\nu}\tilde{\nu}, splits the tau sneutrino into two mass eigenstates: \tilde{\nu} \rightarrow \tilde{\nu}_\pm. The absence of a Z \tilde{\nu}_- \tilde{\nu}_- coupling implies that the lighter mass eignestate, \tilde{\nu}_-, does not annihilate via the s-channel Z-exchange to a low cosmological abundance, and furthermore, halo sneutrinos do not scatter excessively in Ge detectors. For the majority of the relevant parameter space, the event rate in Ge detectors is \geq 10^{-2} events/kg/day. The lepton number violation required for sneutrino CDM implies that the tau neutrino mass is m_{\nu_\tau} \gtrsim 5 MeV, large enough to be excluded by B factory experiments. Events of the form l^+ l^- \not E or jj \not E , with low m_{ll} or m_{jj}, may be observed at LEP2. A seesaw mechanism is investigated as the origin for the lepton number violation, and several other cosmological and particle physics consequences of sneutrino CDM are discussed. |
2203.10089 | Simon Knapen | Rouven Essig, Yonatan Kahn, Simon Knapen, Andreas Ringwald, Natalia
Toro | Snowmass2021 Theory Frontier: Theory Meets the Lab | solicited contribution to snowmass TF09, 23 pages | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We review how theorists have been instrumental in launching and developing
new experiments in the last decade, and comment on the challenges and
opportunities for this program to continue to thrive going forward. This
whitepaper is a solicited contribution to the Snowmass2021 Theory Frontier.
| [
{
"created": "Fri, 18 Mar 2022 17:57:09 GMT",
"version": "v1"
}
] | 2022-03-21 | [
[
"Essig",
"Rouven",
""
],
[
"Kahn",
"Yonatan",
""
],
[
"Knapen",
"Simon",
""
],
[
"Ringwald",
"Andreas",
""
],
[
"Toro",
"Natalia",
""
]
] | We review how theorists have been instrumental in launching and developing new experiments in the last decade, and comment on the challenges and opportunities for this program to continue to thrive going forward. This whitepaper is a solicited contribution to the Snowmass2021 Theory Frontier. |
hep-ph/0306190 | Alan Kostelecky | Robert Bluhm, Alan Kostelecky, Charles Lane, Neil Russell | Probing Lorentz and CPT violation with space-based experiments | 15 pages | Phys.Rev.D68:125008,2003 | 10.1103/PhysRevD.68.125008 | IUHET 455, June 2003 | hep-ph | null | Space-based experiments offer sensitivity to numerous unmeasured effects
involving Lorentz and CPT violation. We provide a classification of clock
sensitivities and present explicit expressions for time variations arising in
such experiments from nonzero coefficients in the Lorentz- and CPT-violating
Standard-Model Extension.
| [
{
"created": "Fri, 20 Jun 2003 19:23:26 GMT",
"version": "v1"
}
] | 2009-09-25 | [
[
"Bluhm",
"Robert",
""
],
[
"Kostelecky",
"Alan",
""
],
[
"Lane",
"Charles",
""
],
[
"Russell",
"Neil",
""
]
] | Space-based experiments offer sensitivity to numerous unmeasured effects involving Lorentz and CPT violation. We provide a classification of clock sensitivities and present explicit expressions for time variations arising in such experiments from nonzero coefficients in the Lorentz- and CPT-violating Standard-Model Extension. |
1203.6321 | Massimiliano Grazzini | D. de Florian, G. Ferrera, M. Grazzini, D. Tommasini | Higgs boson production at the LHC: transverse momentum resummation
effects in the H->2gamma, H->WW->lnu lnu and H->ZZ->4l decay modes | 22 pages, 18 postscript figures | null | 10.1007/JHEP06(2012)132 | ZU-TH 04/12; IFUM-993-FT | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider Standard Model Higgs boson production through gluon--gluon fusion
in hadron collisions. We combine the calculation of the next-to-next-to-leading
order QCD corrections to the inclusive cross section with the resummation of
multiple soft-gluon emissions at small transverse momenta up to
next-to-next-to-leading logarithmic accuracy. The calculation is implemented in
the numerical program HRes and allows us to retain the full kinematics of the
Higgs boson and of its decay products. We present selected numerical results
for the signal cross section at the LHC (\sqrt{s}=8 TeV), in the H->2gamma,
H->WW->lnu lnu and H->ZZ->4l decay channels by using the nominal cuts applied
in current Higgs boson searches by the ATLAS and CMS collaborations.
| [
{
"created": "Wed, 28 Mar 2012 17:34:18 GMT",
"version": "v1"
}
] | 2015-06-04 | [
[
"de Florian",
"D.",
""
],
[
"Ferrera",
"G.",
""
],
[
"Grazzini",
"M.",
""
],
[
"Tommasini",
"D.",
""
]
] | We consider Standard Model Higgs boson production through gluon--gluon fusion in hadron collisions. We combine the calculation of the next-to-next-to-leading order QCD corrections to the inclusive cross section with the resummation of multiple soft-gluon emissions at small transverse momenta up to next-to-next-to-leading logarithmic accuracy. The calculation is implemented in the numerical program HRes and allows us to retain the full kinematics of the Higgs boson and of its decay products. We present selected numerical results for the signal cross section at the LHC (\sqrt{s}=8 TeV), in the H->2gamma, H->WW->lnu lnu and H->ZZ->4l decay channels by using the nominal cuts applied in current Higgs boson searches by the ATLAS and CMS collaborations. |
1104.5389 | Xing Huang | Xing Huang | Anomaly Puzzle, Curved-Spacetime Spinor Hamiltonian, and String
Phenomenology | PhD Thesis, University of Wisconsin-Milwaukee | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the first part of this dissertation, we study two different aspects of
string phenomenology. First we discuss the complementary signals of low mass
superstrings at the proposed electron-positron facilities (ILC and CLIC), in
e+e- and {\gamma} {\gamma} collisions. We examine all relevant four-particle
amplitudes evaluated at the center of mass energies near the mass of lightest
Regge excitations and extract the corresponding pole terms. Secondly, we
consider string realizations of the Randall-Sundrum effective theory and
explore the search for the lowest massive Regge excitation of the gluon and of
the extra (color singlet) gauge boson inherent of D-brane constructions. We
also study the ratio of dijet mass spectra at small and large scattering
angles. We show that with the first fb-1 such a ratio can probe lowest-lying
Regge states for masses ~3.0 TeV. Finally, we propose that the 3.2$\sigma$
excess at about $140 {\rm GeV}$ in the dijet mass spectrum of $W$ + jets
reproted by the CDF Collaboration originates in the decay of a leptophobic $Z'$
that can be related to the U(1) symmetries inherent of D-brane models. In the
remaining parts of this dissertation, we discuss several points that may help
to clarify some questions that remain about the anomaly puzzle in N=1
supersymmetric Yang-Mills theory and we investigate the issue that the Dirac
Hamiltonian of a spin-1/2 particle in a curved background appears to be
non-hermitian.
| [
{
"created": "Thu, 28 Apr 2011 13:39:05 GMT",
"version": "v1"
}
] | 2011-04-29 | [
[
"Huang",
"Xing",
""
]
] | In the first part of this dissertation, we study two different aspects of string phenomenology. First we discuss the complementary signals of low mass superstrings at the proposed electron-positron facilities (ILC and CLIC), in e+e- and {\gamma} {\gamma} collisions. We examine all relevant four-particle amplitudes evaluated at the center of mass energies near the mass of lightest Regge excitations and extract the corresponding pole terms. Secondly, we consider string realizations of the Randall-Sundrum effective theory and explore the search for the lowest massive Regge excitation of the gluon and of the extra (color singlet) gauge boson inherent of D-brane constructions. We also study the ratio of dijet mass spectra at small and large scattering angles. We show that with the first fb-1 such a ratio can probe lowest-lying Regge states for masses ~3.0 TeV. Finally, we propose that the 3.2$\sigma$ excess at about $140 {\rm GeV}$ in the dijet mass spectrum of $W$ + jets reproted by the CDF Collaboration originates in the decay of a leptophobic $Z'$ that can be related to the U(1) symmetries inherent of D-brane models. In the remaining parts of this dissertation, we discuss several points that may help to clarify some questions that remain about the anomaly puzzle in N=1 supersymmetric Yang-Mills theory and we investigate the issue that the Dirac Hamiltonian of a spin-1/2 particle in a curved background appears to be non-hermitian. |
1512.07141 | Alexander Manashov | I.V. Anikin, A.N. Manashov | Baryon octet distribution amplitudes in Wandzura-Wilczek approximation | 7 pages | Phys. Rev. D 93, 034024 (2016) | 10.1103/PhysRevD.93.034024 | DESY 15-254 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study higher twist distribution amplitudes for the SU_F(3) baryon octet.
We identify independent functions for all baryons in the isospin symmetry limit
and calculate the Wandzura-Wilczek contributions to the twist-4 and 5
distributions amplitudes.
| [
{
"created": "Tue, 22 Dec 2015 16:11:56 GMT",
"version": "v1"
}
] | 2016-02-17 | [
[
"Anikin",
"I. V.",
""
],
[
"Manashov",
"A. N.",
""
]
] | We study higher twist distribution amplitudes for the SU_F(3) baryon octet. We identify independent functions for all baryons in the isospin symmetry limit and calculate the Wandzura-Wilczek contributions to the twist-4 and 5 distributions amplitudes. |
hep-ph/9806466 | Serguey Petcov | S. T. Petcov | The Solar Neutrino Problem and Solar Neutrino Oscillations in Vacuum and
in Matter | 48 pages, LATEX file, the text includes 11 figures. Lectures given at
the 36 International School on Nuclear and Particle Physics, March 1 - 8,
1997, Schladming, Austria; to be published in the Proceedings of the School | Lect.Notes Phys.512:281-328,1998 | 10.1007/BFb0106897 | SISSA 30/98/EP | hep-ph | null | The solar neutrino problem is reviewed and the possible vacuum oscillation
and MSW solutions of the problem are considered.
| [
{
"created": "Wed, 24 Jun 1998 14:52:17 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Petcov",
"S. T.",
""
]
] | The solar neutrino problem is reviewed and the possible vacuum oscillation and MSW solutions of the problem are considered. |
hep-ph/0307220 | Andrey Grozin | A. G. Grozin | Perturbative HQET | 17 pages, 13 figures. Lectures at Int. School on Heavy Quark Physics,
Dubna, 27 May - 5 June 2002 | null | null | null | hep-ph | null | Methods of calculation of loop diagrams in Heavy Quark Effective Theory
(HQET) are presented.
| [
{
"created": "Thu, 17 Jul 2003 09:23:40 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Grozin",
"A. G.",
""
]
] | Methods of calculation of loop diagrams in Heavy Quark Effective Theory (HQET) are presented. |
1803.02835 | Chen Sun | Nick Houston, Tianjun Li, Chen Sun | A new solar neutrino channel for grand-unification monopole searches | 27 pages, 9 figures, 1 table | null | 10.1088/1475-7516/2018/10/034 | null | hep-ph astro-ph.HE astro-ph.SR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We identify a previously untapped discovery channel for grand-unification
monopoles, arising from their ability to catalyse the direct decay of protons
into monoenergetic 459 MeV antineutrinos within the Sun. Previous analyses omit
this possibility as it necessarily involves an electroweak suppression factor,
and instead search for the unsuppressed 20-50 MeV neutrinos produced via
two-stage proton decays. By accounting for the relative difference in
interaction cross section and experimental background at typical neutrino
detection experiments, we demonstrate that this new channel in fact possesses
greater discovery potential. As a case in point, using 5326 live days of
Super-Kamiokande exposure we find that $2\;\sigma$ ($3\;\sigma$) deviations in
the 20-50 MeV channel are amplified to $3\;\sigma$ ($4.6\;\sigma$) deviations
in the 459 MeV case. Exploiting correlations between these two channels may
also offer even greater statistical power.
| [
{
"created": "Wed, 7 Mar 2018 19:00:02 GMT",
"version": "v1"
}
] | 2018-10-24 | [
[
"Houston",
"Nick",
""
],
[
"Li",
"Tianjun",
""
],
[
"Sun",
"Chen",
""
]
] | We identify a previously untapped discovery channel for grand-unification monopoles, arising from their ability to catalyse the direct decay of protons into monoenergetic 459 MeV antineutrinos within the Sun. Previous analyses omit this possibility as it necessarily involves an electroweak suppression factor, and instead search for the unsuppressed 20-50 MeV neutrinos produced via two-stage proton decays. By accounting for the relative difference in interaction cross section and experimental background at typical neutrino detection experiments, we demonstrate that this new channel in fact possesses greater discovery potential. As a case in point, using 5326 live days of Super-Kamiokande exposure we find that $2\;\sigma$ ($3\;\sigma$) deviations in the 20-50 MeV channel are amplified to $3\;\sigma$ ($4.6\;\sigma$) deviations in the 459 MeV case. Exploiting correlations between these two channels may also offer even greater statistical power. |
1010.1415 | Gian Francesco Giudice | Gia Dvali, Gian F. Giudice, Cesar Gomez, Alex Kehagias | UV-Completion by Classicalization | 37 pages | null | 10.1007/JHEP08(2011)108 | CERN-PH-TH/2010-226 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We suggest a novel approach to UV-completion of a class of non-renormalizable
theories, according to which the high-energy scattering amplitudes get
unitarized by production of extended classical objects (classicalons), playing
a role analogous to black holes, in the case of non-gravitational theories. The
key property of classicalization is the existence of a classicalizer field that
couples to energy-momentum sources. Such localized sources are excited in
high-energy scattering processes and lead to the formation of classicalons. Two
kinds of natural classicalizers are Nambu-Goldstone bosons (or, equivalently,
longitudinal polarizations of massive gauge fields) and scalars coupled to
energy-momentum type sources. Classicalization has interesting phenomenological
applications for the UV-completion of the Standard Model both with or without
the Higgs. In the Higgless Standard Model the high-energy scattering amplitudes
of longitudinal $W$-bosons self-unitarize via classicalization, without the
help of any new weakly-coupled physics. Alternatively, in the presence of a
Higgs boson, classicalization could explain the stabilization of the hierarchy.
In both scenarios the high-energy scatterings are dominated by the formation of
classicalons, which subsequently decay into many particle states. The
experimental signatures at the LHC are quite distinctive, with sharp
differences in the two cases.
| [
{
"created": "Thu, 7 Oct 2010 12:42:56 GMT",
"version": "v1"
},
{
"created": "Wed, 26 Jan 2011 11:06:38 GMT",
"version": "v2"
}
] | 2015-05-20 | [
[
"Dvali",
"Gia",
""
],
[
"Giudice",
"Gian F.",
""
],
[
"Gomez",
"Cesar",
""
],
[
"Kehagias",
"Alex",
""
]
] | We suggest a novel approach to UV-completion of a class of non-renormalizable theories, according to which the high-energy scattering amplitudes get unitarized by production of extended classical objects (classicalons), playing a role analogous to black holes, in the case of non-gravitational theories. The key property of classicalization is the existence of a classicalizer field that couples to energy-momentum sources. Such localized sources are excited in high-energy scattering processes and lead to the formation of classicalons. Two kinds of natural classicalizers are Nambu-Goldstone bosons (or, equivalently, longitudinal polarizations of massive gauge fields) and scalars coupled to energy-momentum type sources. Classicalization has interesting phenomenological applications for the UV-completion of the Standard Model both with or without the Higgs. In the Higgless Standard Model the high-energy scattering amplitudes of longitudinal $W$-bosons self-unitarize via classicalization, without the help of any new weakly-coupled physics. Alternatively, in the presence of a Higgs boson, classicalization could explain the stabilization of the hierarchy. In both scenarios the high-energy scatterings are dominated by the formation of classicalons, which subsequently decay into many particle states. The experimental signatures at the LHC are quite distinctive, with sharp differences in the two cases. |
2007.10875 | Minh Nguyen | Tony Gherghetta, Minh D. Nguyen | A Composite Higgs with a Heavy Composite Axion | 44 pages, 6 figures, v2: minor changes, version published in JHEP | JHEP 12 (2020) 094 | 10.1007/JHEP12(2020)094 | UMN--TH--3923/20 | hep-ph | http://creativecommons.org/licenses/by-nc-sa/4.0/ | We consider the strong dynamics associated with a composite Higgs model that
simultaneously produces dynamical axions and solves the strong CP problem. The
strong dynamics arises from a new $Sp$ or $SU(4)$ hypercolor gauge group
containing QCD colored hyperfermions that confines at a high scale. The
hypercolor global symmetry is weakly gauged by the Standard Model electroweak
gauge group and an enlarged color group, $SU(N+3) \times SU(N)'$. When
hyperfermion condensates form, they not only lead to an $SU(5)/SO(5)$ composite
Higgs model but also spontaneously break the enlarged color group to $SU(3)_c
\times SU(N)_D$. At lower energies, the $SU(N)_D$ group confines, producing two
dynamical axions that eliminates all CP violation. Furthermore, small
instantons from the $SU(N)'$ group can enhance the axion mass, giving rise to
TeV scale axion masses that can be detected at collider experiments. Our model
provides a way to unify the composite Higgs with dynamical axions, without
introducing new elementary scalar fields, while also extending the range of
axion masses that addresses the strong CP problem.
| [
{
"created": "Tue, 21 Jul 2020 15:06:31 GMT",
"version": "v1"
},
{
"created": "Tue, 22 Dec 2020 21:24:17 GMT",
"version": "v2"
}
] | 2020-12-24 | [
[
"Gherghetta",
"Tony",
""
],
[
"Nguyen",
"Minh D.",
""
]
] | We consider the strong dynamics associated with a composite Higgs model that simultaneously produces dynamical axions and solves the strong CP problem. The strong dynamics arises from a new $Sp$ or $SU(4)$ hypercolor gauge group containing QCD colored hyperfermions that confines at a high scale. The hypercolor global symmetry is weakly gauged by the Standard Model electroweak gauge group and an enlarged color group, $SU(N+3) \times SU(N)'$. When hyperfermion condensates form, they not only lead to an $SU(5)/SO(5)$ composite Higgs model but also spontaneously break the enlarged color group to $SU(3)_c \times SU(N)_D$. At lower energies, the $SU(N)_D$ group confines, producing two dynamical axions that eliminates all CP violation. Furthermore, small instantons from the $SU(N)'$ group can enhance the axion mass, giving rise to TeV scale axion masses that can be detected at collider experiments. Our model provides a way to unify the composite Higgs with dynamical axions, without introducing new elementary scalar fields, while also extending the range of axion masses that addresses the strong CP problem. |
0908.3344 | Ralf Rapp | Ralf Rapp | Dileptons, Charm and Charmonium at Finite Temperature and Chemical
Potential | 15 pages, 24 figures, Proc. of 5. Int. Conf. on Critical Point and
Onset of Deconfinement, BNL, June 08-12, 2009 | PoS CPOD2009:040,2009 | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss how dileptons, open charm and charmonia may be utilized in
heavy-ion collisions to extract information specific to hot and dense matter at
finite quark chemical potential, $\mu_q$. For each observable we briefly
discuss underlying theoretical frameworks and the current status in
interpreting available heavy-ion data at SPS and RHIC energies. Low-mass
dileptons are particularly sensitive to baryonic medium effects in spectral
modifications of the $\rho$ meson, and may serve as an accurate measure of the
fireball lifetime. In the open-charm sector, observable signals may be
generated by a ``critical'' enhancement of scattering rates via $t$-channel
exchange of a soft $\sigma$ mode. For charmonia, finite-$T$ potential models
could be used to extrapolate color-screening effects to finite $\mu_q$ to
facilitate a quantitative evaluation of dissociation rates in the medium.
| [
{
"created": "Sun, 23 Aug 2009 23:12:45 GMT",
"version": "v1"
}
] | 2014-11-20 | [
[
"Rapp",
"Ralf",
""
]
] | We discuss how dileptons, open charm and charmonia may be utilized in heavy-ion collisions to extract information specific to hot and dense matter at finite quark chemical potential, $\mu_q$. For each observable we briefly discuss underlying theoretical frameworks and the current status in interpreting available heavy-ion data at SPS and RHIC energies. Low-mass dileptons are particularly sensitive to baryonic medium effects in spectral modifications of the $\rho$ meson, and may serve as an accurate measure of the fireball lifetime. In the open-charm sector, observable signals may be generated by a ``critical'' enhancement of scattering rates via $t$-channel exchange of a soft $\sigma$ mode. For charmonia, finite-$T$ potential models could be used to extrapolate color-screening effects to finite $\mu_q$ to facilitate a quantitative evaluation of dissociation rates in the medium. |
hep-ph/0010295 | Sheldon Stone | Sheldon Stone | Pathological Science | Presented at Theoretical Advanced Study Institute In Elementary
Particle Physics (Tasi), University of Colorado, Boulder, Colorado June,
2000. To appear in the proceedings. (10/31/2000 - Fixed a reference.) | null | 10.1142/9789812811509_0015 | SUHEP 00-09 | hep-ph hep-ex | null | I discuss examples of what Dr. Irving Langmuir, a Nobel prize winner in
Chemistry, called "the science of things that aren't so." Some of his examples
are reviewed and others from High Energy Physics are added. It is hoped that
discussing these incidents will help us develop an understanding of some
potential pitfalls.
| [
{
"created": "Wed, 25 Oct 2000 21:28:25 GMT",
"version": "v1"
},
{
"created": "Tue, 31 Oct 2000 03:21:02 GMT",
"version": "v2"
}
] | 2017-08-23 | [
[
"Stone",
"Sheldon",
""
]
] | I discuss examples of what Dr. Irving Langmuir, a Nobel prize winner in Chemistry, called "the science of things that aren't so." Some of his examples are reviewed and others from High Energy Physics are added. It is hoped that discussing these incidents will help us develop an understanding of some potential pitfalls. |
1111.6768 | Nathan Hartland | Francesco Cerutti and Nathan Hartland | The NNPDF2.2 Parton Set | 6 pages, Talk given at the International Workshop on Advanced
Computing and Analysis Techniques in Physics Research (ACAT), Uxbridge,
London, September 2011 | null | 10.1088/1742-6596/368/1/012063 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a method developed by the NNPDF Collaboration that allows the
inclusion of new experimental data into an existing set of parton distribution
functions without the need for a complete refit. A Monte Carlo ensemble of PDFs
may be updated by assigning each member of the ensemble a unique weight
determined by Bayesian inference. The reweighted ensemble therefore represents
the probability density of PDFs conditional on both the old and new data. This
method is applied to the inclusion of W-lepton asymmetry data into the NNPDF2.1
fit producing a new PDF set, NNPDF2.2.
| [
{
"created": "Tue, 29 Nov 2011 11:23:19 GMT",
"version": "v1"
},
{
"created": "Tue, 20 Dec 2011 23:52:49 GMT",
"version": "v2"
}
] | 2015-06-03 | [
[
"Cerutti",
"Francesco",
""
],
[
"Hartland",
"Nathan",
""
]
] | We present a method developed by the NNPDF Collaboration that allows the inclusion of new experimental data into an existing set of parton distribution functions without the need for a complete refit. A Monte Carlo ensemble of PDFs may be updated by assigning each member of the ensemble a unique weight determined by Bayesian inference. The reweighted ensemble therefore represents the probability density of PDFs conditional on both the old and new data. This method is applied to the inclusion of W-lepton asymmetry data into the NNPDF2.1 fit producing a new PDF set, NNPDF2.2. |
1606.03102 | Mandip Singh | Mandip Singh | Neutrino mass hierarchy and \delta^{CP} investigation within the
biprobability (P-P^T ) plane | 16 pages,7 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This article illustrates the possibility of investigating mass hierarchy and
CP-violating phase \delta^{CP}, in the context of CP trajectory diagrams in the
bi-probability plane. Separation between normal mass hierarchy (NH) and
inverted mass hierarchy (IH) CP trajectory ellipses in the P-P^T plane seems to
be very promising in order to investigate mass hierarchy. Illustration of
separation between two hierarchy ellipses in the E-L plane is very helping to
cover all the desired base lines and beam energies and also to analyze benefits
and drawbacks at single place. If we know the mass hierarchy, then from the
large sizes of CP trajectory ellipse which is possible at appropriately long
base line (L) and at specific value of beam energy (E), it becomes possible to
investigate at-least narrow ranges of CP/T-violating phase \delta^{CP}. The
Possibility of more than one set of (\theta_{13}; \delta^{CP}) parameters to
correspond to any chosen coordinate in P-P^T plane, known as parameter
degeneracy, may hinder exact determination of mass hierarchy as well as
\delta^{CP} value. To circumvent this degeneracy in the (\theta_{13};
\delta^{CP}) parameter space, in case of opposite sign solutions corresponding
to NH and IH case points toward the need of sufficiently long base lines, so as
to separate opposite hierarchy ellipses to observable separation, and in case
of same sign solutions corresponding to either NH or IH, we need to choose an
experimental configuration with L = 2,535 Km, E = 5 GeV for n=1 scenario.
| [
{
"created": "Thu, 9 Jun 2016 20:03:40 GMT",
"version": "v1"
}
] | 2016-06-13 | [
[
"Singh",
"Mandip",
""
]
] | This article illustrates the possibility of investigating mass hierarchy and CP-violating phase \delta^{CP}, in the context of CP trajectory diagrams in the bi-probability plane. Separation between normal mass hierarchy (NH) and inverted mass hierarchy (IH) CP trajectory ellipses in the P-P^T plane seems to be very promising in order to investigate mass hierarchy. Illustration of separation between two hierarchy ellipses in the E-L plane is very helping to cover all the desired base lines and beam energies and also to analyze benefits and drawbacks at single place. If we know the mass hierarchy, then from the large sizes of CP trajectory ellipse which is possible at appropriately long base line (L) and at specific value of beam energy (E), it becomes possible to investigate at-least narrow ranges of CP/T-violating phase \delta^{CP}. The Possibility of more than one set of (\theta_{13}; \delta^{CP}) parameters to correspond to any chosen coordinate in P-P^T plane, known as parameter degeneracy, may hinder exact determination of mass hierarchy as well as \delta^{CP} value. To circumvent this degeneracy in the (\theta_{13}; \delta^{CP}) parameter space, in case of opposite sign solutions corresponding to NH and IH case points toward the need of sufficiently long base lines, so as to separate opposite hierarchy ellipses to observable separation, and in case of same sign solutions corresponding to either NH or IH, we need to choose an experimental configuration with L = 2,535 Km, E = 5 GeV for n=1 scenario. |
2102.01871 | Suo Tang | Suo Tang | Generation of quasi-monoenergetic positron beams in chirped laser fields | null | Phys. Rev. A 104, 022209 (2021) | 10.1103/PhysRevA.104.022209 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | High energy photons can decay to electron-positron pairs via the nonlinear
Breit-Wheeler process when colliding with an intense laser pulse. The energy
spectrum of the produced particles is broadened because of the variation of
their effective mass in the course of the laser pulse. Applying a suitable
chirp to the laser pulse can narrow the energy distribution of the generated
electrons and positrons. We present a scenario where a high-energy electron
beam is collided with a chirped laser pulse to generate a beam of
quasi-monoenergetic $\gamma$-photons, which then decay in a second chirped, UV
pulse to produce a quasi-monoenergetic source of high-energy electrons and
positrons.
| [
{
"created": "Wed, 3 Feb 2021 04:20:47 GMT",
"version": "v1"
}
] | 2021-08-25 | [
[
"Tang",
"Suo",
""
]
] | High energy photons can decay to electron-positron pairs via the nonlinear Breit-Wheeler process when colliding with an intense laser pulse. The energy spectrum of the produced particles is broadened because of the variation of their effective mass in the course of the laser pulse. Applying a suitable chirp to the laser pulse can narrow the energy distribution of the generated electrons and positrons. We present a scenario where a high-energy electron beam is collided with a chirped laser pulse to generate a beam of quasi-monoenergetic $\gamma$-photons, which then decay in a second chirped, UV pulse to produce a quasi-monoenergetic source of high-energy electrons and positrons. |
1901.04901 | Marek Sch\"onherr | Marek Sch\"onherr | Modelling and tuning in top quark physics | 5 pages, 4 figures, 1 table, contribution to the TOP2018 conference
proceedings | null | null | IPPP/19/4 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this proceedings I discuss the general strategy and impact of tuning
Monte-Carlo event generators for physics processes involving top quarks.
Special emphasis is put on disinguishing the different usages of event
generators in the experiments and the subsequent implications on the tuning
process. The current status of determining tune uncertainties is also
discussed.
| [
{
"created": "Tue, 15 Jan 2019 16:10:34 GMT",
"version": "v1"
}
] | 2019-01-16 | [
[
"Schönherr",
"Marek",
""
]
] | In this proceedings I discuss the general strategy and impact of tuning Monte-Carlo event generators for physics processes involving top quarks. Special emphasis is put on disinguishing the different usages of event generators in the experiments and the subsequent implications on the tuning process. The current status of determining tune uncertainties is also discussed. |
2109.02671 | Maria Ubiali Dr | Richard D. Ball, Stefano Carrazza, Juan Cruz-Martinez, Luigi Del
Debbio, Stefano Forte, Tommaso Giani, Shayan Iranipour, Zahari Kassabov, Jose
I. Latorre, Emanuele R. Nocera, Rosalyn L. Pearson, Juan Rojo, Roy Stegeman,
Christopher Schwan, Maria Ubiali, Cameron Voisey and Michael Wilson | An open-source machine learning framework for global analyses of parton
distributions | 14 pages, 4 figures. A companion paper describes the NNPDF4.0 PDFs | null | null | Edinburgh 2021/13, Nikhef-2021-020, TIF-UNIMI-2021-12 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We present the software framework underlying the NNPDF4.0 global
determination of parton distribution functions (PDFs). The code is released
under an open source licence and is accompanied by extensive documentation and
examples. The code base is composed by a PDF fitting package, tools to handle
experimental data and to efficiently compare it to theoretical predictions, and
a versatile analysis framework. In addition to ensuring the reproducibility of
the NNPDF4.0 (and subsequent) determination, the public release of the NNPDF
fitting framework enables a number of phenomenological applications and the
production of PDF fits under user-defined data and theory assumptions.
| [
{
"created": "Mon, 6 Sep 2021 18:00:06 GMT",
"version": "v1"
}
] | 2021-09-08 | [
[
"Ball",
"Richard D.",
""
],
[
"Carrazza",
"Stefano",
""
],
[
"Cruz-Martinez",
"Juan",
""
],
[
"Del Debbio",
"Luigi",
""
],
[
"Forte",
"Stefano",
""
],
[
"Giani",
"Tommaso",
""
],
[
"Iranipour",
"Shayan",
""... | We present the software framework underlying the NNPDF4.0 global determination of parton distribution functions (PDFs). The code is released under an open source licence and is accompanied by extensive documentation and examples. The code base is composed by a PDF fitting package, tools to handle experimental data and to efficiently compare it to theoretical predictions, and a versatile analysis framework. In addition to ensuring the reproducibility of the NNPDF4.0 (and subsequent) determination, the public release of the NNPDF fitting framework enables a number of phenomenological applications and the production of PDF fits under user-defined data and theory assumptions. |
1101.2437 | Wujun Huo Dr | Qin XiuMei, Wujun Huo, Xiaofang Yang | New Physics effects on decay $B_s \to \gamma\gamma$ in Technicolor Model | 9 pages, 4 figures | Chin. Phys. C33:252-255, 2009 | 10.1088/1674-1137/33/4/003 | null | hep-ph | http://creativecommons.org/licenses/by/3.0/ | In this paper we calculate the contributions to the branching ratio of $B_s
\to \gamma\gamma$ from the charged Pseudo-Goldstone bosons appeared in one
generation Technicolor model. We find that the theoretical values of the
branching ratio, $BR(B_s\to\gamma\gamma)$, including the contributions of PGBs,
$P^\pm$ and $P^{\pm}_8$, are much different from the $SM$ prediction. The new
physics effects can be enhance 2-3 levels to $SM$ result. It is shown that the
decay $B_s\to \gamma\gamma$ can give the test the new physics signals from the
technicolor model.
| [
{
"created": "Wed, 12 Jan 2011 20:18:57 GMT",
"version": "v1"
}
] | 2015-05-27 | [
[
"XiuMei",
"Qin",
""
],
[
"Huo",
"Wujun",
""
],
[
"Yang",
"Xiaofang",
""
]
] | In this paper we calculate the contributions to the branching ratio of $B_s \to \gamma\gamma$ from the charged Pseudo-Goldstone bosons appeared in one generation Technicolor model. We find that the theoretical values of the branching ratio, $BR(B_s\to\gamma\gamma)$, including the contributions of PGBs, $P^\pm$ and $P^{\pm}_8$, are much different from the $SM$ prediction. The new physics effects can be enhance 2-3 levels to $SM$ result. It is shown that the decay $B_s\to \gamma\gamma$ can give the test the new physics signals from the technicolor model. |
hep-ph/0303017 | Gunnar Martens | Gunnar Martens, Carsten Greiner, Stefan Leupold and Ulrich Mosel
(University of Giessen, Germany) | Chromofields of Strings and Baryons | Contributions to QNP 2002, Quarks and Nuclear Physics, Juelich,
Germany 3 pages, 10 eps figures | Eur.Phys.J. A18 (2003) 223-226 | 10.1140/epja/i2002-10303-6 | null | hep-ph nucl-th | null | We calculate color electric fields of quark/antiquark ($\bar{q}q$) and 3
quark ($qqq$) systems within the chromodielectric model (CDM). We explicitly
evaluate the string tension of flux tubes in the $\bar{q}q$--system and analyze
their profile. To reproduce results of lattice calculations we use a bag
pressure $B = (320 MeV)^4$ from which an effective strong coupling constant
$\alpha_s \approx 0.3$ follows. With these parameters we get a $Y$ shaped
configuration for large $qqq$--systems.
| [
{
"created": "Tue, 4 Mar 2003 12:48:54 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Martens",
"Gunnar",
"",
"University of Giessen, Germany"
],
[
"Greiner",
"Carsten",
"",
"University of Giessen, Germany"
],
[
"Leupold",
"Stefan",
"",
"University of Giessen, Germany"
],
[
"Mosel",
"Ulrich",
"",
"University of Giessen, G... | We calculate color electric fields of quark/antiquark ($\bar{q}q$) and 3 quark ($qqq$) systems within the chromodielectric model (CDM). We explicitly evaluate the string tension of flux tubes in the $\bar{q}q$--system and analyze their profile. To reproduce results of lattice calculations we use a bag pressure $B = (320 MeV)^4$ from which an effective strong coupling constant $\alpha_s \approx 0.3$ follows. With these parameters we get a $Y$ shaped configuration for large $qqq$--systems. |
1212.3206 | Michela D'Onofrio | Michela D'Onofrio, Kari Rummukainen and Anders Tranberg | The sphaleron rate at the electroweak crossover with 125 GeV Higgs mass | 7 pages, 2 figures, presented at "The 30th International Symposium on
Lattice Field Theory", June 24 - 29, 2012, Cairns, Australia | PoS(Lattice 2012)055 | null | null | hep-ph hep-lat | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We measure the sphaleron rate with the physical parameters of the Standard
Model. In particular, we plug into the calculations the recently found Higgs
mass m_H = 125 GeV. The sphaleron rate tells us about the efficiency of baryon
number violation through sphaleron transitions. These occur above the
electroweak scale of 100 GeV and get exponentially suppressed at temperatures
substantially below the electroweak crossover. The sphaleron rate enters
computations of Baryogenesis via Leptogenesis, where it converts non-zero
lepton number into non-zero baryon number. We simulate the effective
electroweak theory on the lattice with multicanonical and real-time methods to
calculate the sphaleron rate as a function of temperature through the
electroweak crossover.
| [
{
"created": "Thu, 13 Dec 2012 16:07:12 GMT",
"version": "v1"
}
] | 2012-12-14 | [
[
"D'Onofrio",
"Michela",
""
],
[
"Rummukainen",
"Kari",
""
],
[
"Tranberg",
"Anders",
""
]
] | We measure the sphaleron rate with the physical parameters of the Standard Model. In particular, we plug into the calculations the recently found Higgs mass m_H = 125 GeV. The sphaleron rate tells us about the efficiency of baryon number violation through sphaleron transitions. These occur above the electroweak scale of 100 GeV and get exponentially suppressed at temperatures substantially below the electroweak crossover. The sphaleron rate enters computations of Baryogenesis via Leptogenesis, where it converts non-zero lepton number into non-zero baryon number. We simulate the effective electroweak theory on the lattice with multicanonical and real-time methods to calculate the sphaleron rate as a function of temperature through the electroweak crossover. |
2303.02175 | Oleg Komoltsev | Tyler Gorda, Oleg Komoltsev, Aleksi Kurkela, Aleksas Mazeliauskas | Bayesian uncertainty quantification of perturbative QCD input to the
neutron-star equation of state | Version 2 - published version, minor changes. 12 pages, 10 figs | null | 10.1007/JHEP06(2023)002 | null | hep-ph astro-ph.HE nucl-th | http://creativecommons.org/licenses/by/4.0/ | The equation of state of neutron-star cores can be constrained by requiring a
consistent connection to the perturbative Quantum Chromodynamics (QCD)
calculations at high densities. The constraining power of the QCD input depends
on uncertainties from missing higher-order terms, the choice of the unphysical
renormalization scale, and the reference density where QCD calculations are
performed. Within a Bayesian approach, we discuss the convergence of the
perturbative QCD series, quantify its uncertainties at high densities, and
present a framework to systematically propagate the uncertainties down to
neutron-star densities. We find that the effect of the QCD input on the
neutron-star inference is insensitive to the various unphysical choices made in
the uncertainty estimation.
| [
{
"created": "Fri, 3 Mar 2023 19:00:06 GMT",
"version": "v1"
},
{
"created": "Fri, 28 Jul 2023 13:25:12 GMT",
"version": "v2"
}
] | 2023-07-31 | [
[
"Gorda",
"Tyler",
""
],
[
"Komoltsev",
"Oleg",
""
],
[
"Kurkela",
"Aleksi",
""
],
[
"Mazeliauskas",
"Aleksas",
""
]
] | The equation of state of neutron-star cores can be constrained by requiring a consistent connection to the perturbative Quantum Chromodynamics (QCD) calculations at high densities. The constraining power of the QCD input depends on uncertainties from missing higher-order terms, the choice of the unphysical renormalization scale, and the reference density where QCD calculations are performed. Within a Bayesian approach, we discuss the convergence of the perturbative QCD series, quantify its uncertainties at high densities, and present a framework to systematically propagate the uncertainties down to neutron-star densities. We find that the effect of the QCD input on the neutron-star inference is insensitive to the various unphysical choices made in the uncertainty estimation. |
hep-ph/0405187 | Helmut Eberl Dr. | H. Eberl, W. Majerotto, Y. Yamada | Full one-loop corrections to SUSY Higgs boson decays into charginos | 15 pages, 9 figures | Phys.Lett. B597 (2004) 275-284 | 10.1016/j.physletb.2004.07.021 | HEPHY-PUB 788/04, TU-716 | hep-ph | null | We present the decay widths of the heavier Higgs bosons $H^0$ and $A^0$ into
chargino pairs in the minimal supersymmetric standard model, including full
one-loop corrections. All parameters for charginos are renormalized in the
on-shell scheme. The importance of the corrections to the chargino mass matrix
and mixing matrices is pointed out. The full corrections are typically of the
order of 10 %.
| [
{
"created": "Wed, 19 May 2004 14:41:33 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Eberl",
"H.",
""
],
[
"Majerotto",
"W.",
""
],
[
"Yamada",
"Y.",
""
]
] | We present the decay widths of the heavier Higgs bosons $H^0$ and $A^0$ into chargino pairs in the minimal supersymmetric standard model, including full one-loop corrections. All parameters for charginos are renormalized in the on-shell scheme. The importance of the corrections to the chargino mass matrix and mixing matrices is pointed out. The full corrections are typically of the order of 10 %. |
hep-ph/0202158 | Danny Marfatia | V. Barger, D. Marfatia and B.P. Wood | Supernova 1987A did not test the neutrino mass hierarchy | 15 pages, 9 figures | Phys.Lett.B532:19-28,2002 | 10.1016/S0370-2693(02)01546-0 | MADPH-02-1257 | hep-ph astro-ph hep-ex | null | We dispel the misconception that data from SN 1987A favor the normal neutrino
mass hierarchy over the inverted hierarchy for $\sin^2 \theta_{13} \gsim
10^{-4}$. We find comparable fits for the two hierarchies. No bound can be
placed on the mixing angle $\theta_{13}$ even at the 1$\sigma$ level.
| [
{
"created": "Mon, 18 Feb 2002 20:59:07 GMT",
"version": "v1"
}
] | 2009-09-15 | [
[
"Barger",
"V.",
""
],
[
"Marfatia",
"D.",
""
],
[
"Wood",
"B. P.",
""
]
] | We dispel the misconception that data from SN 1987A favor the normal neutrino mass hierarchy over the inverted hierarchy for $\sin^2 \theta_{13} \gsim 10^{-4}$. We find comparable fits for the two hierarchies. No bound can be placed on the mixing angle $\theta_{13}$ even at the 1$\sigma$ level. |
2212.06019 | Rene Poncelet | Rene Poncelet | Precision comparisons between theory and data in $t\bar{t}$-production
at the LHC | Talk at the 15th International Workshop on Top Quark Physics, Durham,
UK, 4-9 September 2022 | null | null | Cavendish-HEP-22/10 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | NNLO QCD corrections to the production and decay of top-quark pairs allow
performing precision phenomenology in inclusive and fiducial phase spaces.
State-of-the-art predictions for top-quark pair production and their comparison
to recent collider data are discussed.
| [
{
"created": "Mon, 12 Dec 2022 16:32:43 GMT",
"version": "v1"
}
] | 2022-12-13 | [
[
"Poncelet",
"Rene",
""
]
] | NNLO QCD corrections to the production and decay of top-quark pairs allow performing precision phenomenology in inclusive and fiducial phase spaces. State-of-the-art predictions for top-quark pair production and their comparison to recent collider data are discussed. |
0901.2955 | Peter Orland | Peter Orland and Jing Xiao (Baruch College, CUNY and Grad. School and
Univ. Center, CUNY) | Longitudinal Rescaling and High-Energy Effective Actions | Version to appear in Physical Review D | Phys.Rev.D80:016005,2009 | 10.1103/PhysRevD.80.016005 | BCCUNY-HEP/09-02 | hep-ph hep-lat hep-th nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Under a rescaling of longitudinal coordinates $x^{0,3}$ by a factor $\lambda$
which is taken to zero, the classical QCD action simplifies dramatically. This
is the high-energy limit, as $\lambda$ is of order $s^{-1/2}$, where $s$ is the
center-of-mass energy squared of a hadronic collision. We find the quantum
corrections to the rescaled action at one loop, in particular finding the
anomalous powers of $\lambda$ in this action, for $\lambda$ close to unity. The
method is an integration over high-momentum components of the gauge field. This
is a Wilsonian renormalization procedure, and counterterms are needed to make
the sharp-momentum cut-off gauge invariant. Our result for the quantum action
is found, assuming that the logarithm of $\lambda$ is small, which is essential
for the validity of perturbation theory. If $\lambda$ is sufficiently small (so
that its logarithm is large), then the perturbative renormalization group
breaks down. This is due to uncontrollable fluctuations of the longitudinal
chromomagnetic field.
| [
{
"created": "Mon, 19 Jan 2009 23:34:22 GMT",
"version": "v1"
},
{
"created": "Wed, 28 Jan 2009 22:34:43 GMT",
"version": "v2"
},
{
"created": "Thu, 23 Apr 2009 20:37:52 GMT",
"version": "v3"
},
{
"created": "Mon, 22 Jun 2009 11:58:11 GMT",
"version": "v4"
}
] | 2009-09-02 | [
[
"Orland",
"Peter",
"",
"Baruch College, CUNY and Grad. School and\n Univ. Center, CUNY"
],
[
"Xiao",
"Jing",
"",
"Baruch College, CUNY and Grad. School and\n Univ. Center, CUNY"
]
] | Under a rescaling of longitudinal coordinates $x^{0,3}$ by a factor $\lambda$ which is taken to zero, the classical QCD action simplifies dramatically. This is the high-energy limit, as $\lambda$ is of order $s^{-1/2}$, where $s$ is the center-of-mass energy squared of a hadronic collision. We find the quantum corrections to the rescaled action at one loop, in particular finding the anomalous powers of $\lambda$ in this action, for $\lambda$ close to unity. The method is an integration over high-momentum components of the gauge field. This is a Wilsonian renormalization procedure, and counterterms are needed to make the sharp-momentum cut-off gauge invariant. Our result for the quantum action is found, assuming that the logarithm of $\lambda$ is small, which is essential for the validity of perturbation theory. If $\lambda$ is sufficiently small (so that its logarithm is large), then the perturbative renormalization group breaks down. This is due to uncontrollable fluctuations of the longitudinal chromomagnetic field. |
1010.2018 | Alexander Rudenko S. | A.E. Blinov and A.S. Rudenko | Upper Limits on Electric and Weak Dipole Moments of W-Boson | 9 pages, 4 figures | Phys. Lett. B699:287-290, 2011 | 10.1016/j.physletb.2011.04.021 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The total cross-sections of the reaction e+e- --> W+W-, as measured at LEP-II
at centre-of-mass energies between 183 and 207 GeV are used to derive the upper
limits on the parameters of CP-violating (P-odd and C-even) triple gauge-boson
couplings WW\gamma and WWZ. The 95% CL limits |\widetilde{\kappa}_Z|<0.13 and
|\widetilde{\lambda}_Z|<0.31 are obtained assuming local SU(2)_L x U(1)_Y gauge
invariance. Our results are comparable with the previous ones obtained through
the analysis of the W decay products. We also discuss the upper limits on the
electric dipole moment (EDM) of the W-boson, which follow from the precision
measurements of the electron and neutron EDM.
| [
{
"created": "Mon, 11 Oct 2010 07:17:03 GMT",
"version": "v1"
},
{
"created": "Mon, 11 Apr 2011 11:21:24 GMT",
"version": "v2"
}
] | 2015-03-17 | [
[
"Blinov",
"A. E.",
""
],
[
"Rudenko",
"A. S.",
""
]
] | The total cross-sections of the reaction e+e- --> W+W-, as measured at LEP-II at centre-of-mass energies between 183 and 207 GeV are used to derive the upper limits on the parameters of CP-violating (P-odd and C-even) triple gauge-boson couplings WW\gamma and WWZ. The 95% CL limits |\widetilde{\kappa}_Z|<0.13 and |\widetilde{\lambda}_Z|<0.31 are obtained assuming local SU(2)_L x U(1)_Y gauge invariance. Our results are comparable with the previous ones obtained through the analysis of the W decay products. We also discuss the upper limits on the electric dipole moment (EDM) of the W-boson, which follow from the precision measurements of the electron and neutron EDM. |
2302.14285 | Sarira Sahu | Jos\'e F. Nieves and Sarira Sahu | Model for the propagation of fermions in a Bose-Einstein condensate | 20 pages, one figure, To be published in Phys. Rev. D | null | 10.1103/PhysRevD.107.116012 | null | hep-ph astro-ph.HE | http://creativecommons.org/licenses/by/4.0/ | We consider the dispersion relations of fermions that propagate in the
background of a scalar Bose-Einstein condensate. Some illustrative examples are
discussed using simple Yukawa-type coupling models between the fermions and the
scalar fields. The dispersion relations are determined explicitly in those
cases, to the lowest order. The method also allows to determine the corrections
to the dispersion relations due to the interactions with the excitations of the
Bose-Einstein condensate. Possible applications of the results to the case of
neutrinos are indicated.
| [
{
"created": "Tue, 28 Feb 2023 03:36:54 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Jun 2023 03:43:02 GMT",
"version": "v2"
}
] | 2023-06-21 | [
[
"Nieves",
"José F.",
""
],
[
"Sahu",
"Sarira",
""
]
] | We consider the dispersion relations of fermions that propagate in the background of a scalar Bose-Einstein condensate. Some illustrative examples are discussed using simple Yukawa-type coupling models between the fermions and the scalar fields. The dispersion relations are determined explicitly in those cases, to the lowest order. The method also allows to determine the corrections to the dispersion relations due to the interactions with the excitations of the Bose-Einstein condensate. Possible applications of the results to the case of neutrinos are indicated. |
hep-ph/0210083 | Alexandre Grezzi de Miranda Schmidt | Alfredo T. Suzuki, Esdras S. Santos, Alexandre G. M. Schmidt | General Formula for N-point One-loop Feynman Integrals | Latex, 36 pages, uses axodraw.sty. Version-2: misprints in the
appendix corrected, reference added | null | null | null | hep-ph | null | The negative dimensional integration method (NDIM) is a technique where
several difficulties concerning loop integration can be overcome. From usual
covariant gauges to complicated Coulomb gauge integrals, and even the trickiest
light-cone integrals one can apply the methodology of NDIM. In this work we
show how to construct a general formula -- we mean arbitrary exponents of
propagators, off-shell external momenta and distinct massive propagators -- for
one-loop scalar integrals, for {\it covariant} gauges, and apply it to one
through six-point loop integrals. We present detailed analysis of pentagon and
hexagon scalar integrals for massive/massless internal particles being external
momenta on or off mass shell.
| [
{
"created": "Fri, 4 Oct 2002 18:14:41 GMT",
"version": "v1"
},
{
"created": "Thu, 10 Oct 2002 12:22:33 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Suzuki",
"Alfredo T.",
""
],
[
"Santos",
"Esdras S.",
""
],
[
"Schmidt",
"Alexandre G. M.",
""
]
] | The negative dimensional integration method (NDIM) is a technique where several difficulties concerning loop integration can be overcome. From usual covariant gauges to complicated Coulomb gauge integrals, and even the trickiest light-cone integrals one can apply the methodology of NDIM. In this work we show how to construct a general formula -- we mean arbitrary exponents of propagators, off-shell external momenta and distinct massive propagators -- for one-loop scalar integrals, for {\it covariant} gauges, and apply it to one through six-point loop integrals. We present detailed analysis of pentagon and hexagon scalar integrals for massive/massless internal particles being external momenta on or off mass shell. |
2205.01669 | Yongchao Zhang | Shyam Balaji, P. S. Bhupal Dev, Joseph Silk, Yongchao Zhang | Improved stellar limits on a light CP-even scalar | 31 pages, 11 figures, 2 tables, calculations updated, more references | null | 10.1088/1475-7516/2022/12/024 | null | hep-ph astro-ph.CO astro-ph.SR | http://creativecommons.org/licenses/by/4.0/ | We derive improved stellar luminosity limits on a generic light CP-even
scalar field $S$ mixing with the Standard Model (SM) Higgs boson from the
supernova SN1987A, the Sun, red giants (RGs) and white dwarfs (WDs). For the
first time, we include the geometric effects for the decay and absorption of
$S$ particles in the stellar interior. For SN1987A and the Sun, we also take
into account the detailed stellar profiles. We find that a broad range of the
scalar mass and mixing angle can be excluded by our updated astrophysical
constraints. For instance, SN1987A excludes $1.0\times10^{-7} \lesssim
\sin\theta \lesssim 3.0\times 10^{-5}$ and scalar mass up to 219 MeV, which
covers the cosmological blind spot with a high reheating temperature. The
updated solar limit excludes the mixing angle in the range of $1.5\times
10^{-12} < \sin\theta < 1$, with scalar mass up to 45 keV. The RG and WD limits
are updated to $5.3\times 10^{-13} < \sin \theta < 0.39$ and $2.8\times
10^{-18} < \sin \theta < 1.8\times 10^{-4}$, with scalar mass up to 392 keV and
290 keV, respectively.
| [
{
"created": "Tue, 3 May 2022 17:59:58 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Jun 2022 08:22:52 GMT",
"version": "v2"
}
] | 2022-12-21 | [
[
"Balaji",
"Shyam",
""
],
[
"Dev",
"P. S. Bhupal",
""
],
[
"Silk",
"Joseph",
""
],
[
"Zhang",
"Yongchao",
""
]
] | We derive improved stellar luminosity limits on a generic light CP-even scalar field $S$ mixing with the Standard Model (SM) Higgs boson from the supernova SN1987A, the Sun, red giants (RGs) and white dwarfs (WDs). For the first time, we include the geometric effects for the decay and absorption of $S$ particles in the stellar interior. For SN1987A and the Sun, we also take into account the detailed stellar profiles. We find that a broad range of the scalar mass and mixing angle can be excluded by our updated astrophysical constraints. For instance, SN1987A excludes $1.0\times10^{-7} \lesssim \sin\theta \lesssim 3.0\times 10^{-5}$ and scalar mass up to 219 MeV, which covers the cosmological blind spot with a high reheating temperature. The updated solar limit excludes the mixing angle in the range of $1.5\times 10^{-12} < \sin\theta < 1$, with scalar mass up to 45 keV. The RG and WD limits are updated to $5.3\times 10^{-13} < \sin \theta < 0.39$ and $2.8\times 10^{-18} < \sin \theta < 1.8\times 10^{-4}$, with scalar mass up to 392 keV and 290 keV, respectively. |
1507.00170 | Werner Rodejohann | Heinrich P\"as, Werner Rodejohann | Neutrinoless Double Beta Decay | Review prepared for the NJP focus issue on "Neutrino Physics". 23
pages, 10 figures | null | 10.1088/1367-2630/17/11/115010 | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review the potential to probe new physics with neutrinoless double beta
decay $(A,Z) \to (A,Z+2) + 2 e^-$. Both the standard long-range light neutrino
mechanism as well as short-range mechanisms mediated by heavy particles are
discussed. We also stress aspects of the connection to lepton number violation
at colliders and the implications for baryogenesis.
| [
{
"created": "Wed, 1 Jul 2015 10:04:23 GMT",
"version": "v1"
}
] | 2015-12-09 | [
[
"Päs",
"Heinrich",
""
],
[
"Rodejohann",
"Werner",
""
]
] | We review the potential to probe new physics with neutrinoless double beta decay $(A,Z) \to (A,Z+2) + 2 e^-$. Both the standard long-range light neutrino mechanism as well as short-range mechanisms mediated by heavy particles are discussed. We also stress aspects of the connection to lepton number violation at colliders and the implications for baryogenesis. |
2001.08459 | Maozhi Yang | Ying-Quan Peng and Mao-Zhi Yang | Study of semileptonic decay of $\bar{B}_s^0\to \phi l^+ l^-$ in QCD sum
rule | 25 pages, 4 figures, more content added | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work we study the semi-leptonic decay of $\bar{B}_s^0\to \phi l^+
l^-$($l=e, \mu, \tau$) with QCD sum rule method. We calculate the
$\bar{B}_s^0\to \phi$ translation form factors relevant to this semi-leptonic
decay, then the branching ratios of $\bar{B}_s^0\to \phi l^+ l^-$($l=e, \mu,
\tau$) decays are calculated with the form factors obtained here. Our result
for the branching ratio of $\bar{B}_s^0\to \phi\mu^+ \mu^-$ agrees very well
with the recent experimental data. For the unmeasured decay modes such as
$\bar{B}_s^0\to \phi e^+ e^-$ and $\bar{B}_s^0\to \phi\tau^+ \tau^-$, we give
theoretical predictions.
| [
{
"created": "Thu, 23 Jan 2020 11:45:48 GMT",
"version": "v1"
},
{
"created": "Wed, 2 Sep 2020 01:43:46 GMT",
"version": "v2"
}
] | 2020-09-03 | [
[
"Peng",
"Ying-Quan",
""
],
[
"Yang",
"Mao-Zhi",
""
]
] | In this work we study the semi-leptonic decay of $\bar{B}_s^0\to \phi l^+ l^-$($l=e, \mu, \tau$) with QCD sum rule method. We calculate the $\bar{B}_s^0\to \phi$ translation form factors relevant to this semi-leptonic decay, then the branching ratios of $\bar{B}_s^0\to \phi l^+ l^-$($l=e, \mu, \tau$) decays are calculated with the form factors obtained here. Our result for the branching ratio of $\bar{B}_s^0\to \phi\mu^+ \mu^-$ agrees very well with the recent experimental data. For the unmeasured decay modes such as $\bar{B}_s^0\to \phi e^+ e^-$ and $\bar{B}_s^0\to \phi\tau^+ \tau^-$, we give theoretical predictions. |
1706.00346 | Henning Bahl | Henning Bahl, Sven Heinemeyer, Wolfgang Hollik, Georg Weiglein | Reconciling EFT and hybrid calculations of the light MSSM Higgs-boson
mass | 31 pages, 5 figures, matches version published in EPJC | null | 10.1140/epjc/s10052-018-5544-3 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Various methods are used in the literature for predicting the lightest
CP-even Higgs boson mass in the Minimal Supersymmetric Standard Model (MSSM).
Fixed-order diagrammatic calculations capture all effects at a given order and
yield accurate results for scales of supersymmetric (SUSY) particles that are
not separated too much from the weak scale. Effective field theory calculations
allow a resummation of large logarithmic contributions up to all orders and
therefore yield accurate results for a high SUSY scale. A hybrid approach,
where both methods have been combined, is implemented in the computer code
FeynHiggs. So far, however, at large scales sizeable differences have been
observed between FeynHiggs and other pure EFT codes. In this work, the various
approaches are analytically compared with each other in a simple scenario in
which all SUSY mass scales are chosen to be equal to each other. Three main
sources are identified that account for the major part of the observed
differences. Firstly, it is shown that the scheme conversion of the input
parameters that is commonly used for the comparison of fixed-order results is
not adequate for the comparison of results containing a series of higher-order
logarithms. Secondly, the treatment of higher-order terms arising from the
determination of the Higgs propagator pole is addressed. Thirdly, the effect of
different parametrizations in particular of the top Yukawa coupling in the
non-logarithmic terms is investigated. Taking into account all of these
effects, in the considered simple scenario very good agreement is found for
scales above 1 TeV between the results obtained using the EFT approach and the
hybrid approach of FeynHiggs.
| [
{
"created": "Thu, 1 Jun 2017 15:24:12 GMT",
"version": "v1"
},
{
"created": "Tue, 30 Jan 2018 14:57:57 GMT",
"version": "v2"
}
] | 2018-02-14 | [
[
"Bahl",
"Henning",
""
],
[
"Heinemeyer",
"Sven",
""
],
[
"Hollik",
"Wolfgang",
""
],
[
"Weiglein",
"Georg",
""
]
] | Various methods are used in the literature for predicting the lightest CP-even Higgs boson mass in the Minimal Supersymmetric Standard Model (MSSM). Fixed-order diagrammatic calculations capture all effects at a given order and yield accurate results for scales of supersymmetric (SUSY) particles that are not separated too much from the weak scale. Effective field theory calculations allow a resummation of large logarithmic contributions up to all orders and therefore yield accurate results for a high SUSY scale. A hybrid approach, where both methods have been combined, is implemented in the computer code FeynHiggs. So far, however, at large scales sizeable differences have been observed between FeynHiggs and other pure EFT codes. In this work, the various approaches are analytically compared with each other in a simple scenario in which all SUSY mass scales are chosen to be equal to each other. Three main sources are identified that account for the major part of the observed differences. Firstly, it is shown that the scheme conversion of the input parameters that is commonly used for the comparison of fixed-order results is not adequate for the comparison of results containing a series of higher-order logarithms. Secondly, the treatment of higher-order terms arising from the determination of the Higgs propagator pole is addressed. Thirdly, the effect of different parametrizations in particular of the top Yukawa coupling in the non-logarithmic terms is investigated. Taking into account all of these effects, in the considered simple scenario very good agreement is found for scales above 1 TeV between the results obtained using the EFT approach and the hybrid approach of FeynHiggs. |
2104.04942 | Quan-Yi Hu | Quan-Yi Hu, Xin-Qiang Li, Xiao-Long Mu, Ya-Dong Yang, Dong-Hui Zheng | New physics in the angular distribution of $B_c^- \to J/\psi (\to \mu^+
\mu^-)\tau^- (\to \pi^- \nu_\tau)\bar{\nu}_\tau$ decay | 29 pages, 3 figures, matches to the version published in JHEP | null | 10.1007/JHEP06(2021)075 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In $B_c^- \to J/\psi (\to \mu^+ \mu^-)\tau^-\bar{\nu}_\tau$ decay, the
three-momentum $\boldsymbol{p}_{\tau^-}$ cannot be determined accurately due to
the decay products of $\tau^-$ inevitably include an undetected $\nu_{\tau}$.
As a consequence, the angular distribution of this decay cannot be measured. In
this work, we construct a {\it measurable} angular distribution by considering
the subsequent decay $\tau^- \to \pi^- \nu_\tau$. The full cascade decay is
$B_c^- \to J/\psi (\to \mu^+ \mu^-)\tau^- (\to \pi^- \nu_\tau)\bar{\nu}_\tau$,
in which the three-momenta $\boldsymbol{p}_{\mu^+}$, $\boldsymbol{p}_{\mu^-}$,
and $\boldsymbol{p}_{\pi^-}$ can be measured. The five-fold differential
angular distribution containing all Lorentz structures of the new physics (NP)
effective operators can be written in terms of twelve angular observables
$\mathcal{I}_i (q^2, E_\pi)$. Integrating over the energy of pion $E_\pi$, we
construct twelve normalized angular observables $\widehat{\mathcal{I}}_i(q^2)$
and two lepton-flavor-universality ratios $R(P_{L,T}^{J/\psi})(q^2)$. Based on
the $B_c \to J/\psi$ form factors calculated by the latest lattice QCD and sum
rule, we predict the $q^2$ distribution of all $\widehat{\mathcal{I}}_i$ and
$R(P_{L,T}^{J/\psi})$ both within the Standard Model and in eight NP benchmark
points. We find that the benchmark BP2 (corresponding to the hypothesis of
tensor operator) has the greatest effect on all $\widehat{\mathcal{I}}_{i}$ and
$R(P_{L,T}^{J/\psi})$, except $\widehat{\mathcal{I}}_{5}$. The ratios
$R(P_{L,T}^{J/\psi})$ are more sensitive to the NP with pseudo-scalar operators
than the $\widehat{\mathcal{I}}_{i}$. Finally, we discuss the symmetries in the
angular observables and present a model-independent method to determine the
existence of tensor operators.
| [
{
"created": "Sun, 11 Apr 2021 07:27:50 GMT",
"version": "v1"
},
{
"created": "Thu, 10 Jun 2021 10:40:11 GMT",
"version": "v2"
}
] | 2021-06-30 | [
[
"Hu",
"Quan-Yi",
""
],
[
"Li",
"Xin-Qiang",
""
],
[
"Mu",
"Xiao-Long",
""
],
[
"Yang",
"Ya-Dong",
""
],
[
"Zheng",
"Dong-Hui",
""
]
] | In $B_c^- \to J/\psi (\to \mu^+ \mu^-)\tau^-\bar{\nu}_\tau$ decay, the three-momentum $\boldsymbol{p}_{\tau^-}$ cannot be determined accurately due to the decay products of $\tau^-$ inevitably include an undetected $\nu_{\tau}$. As a consequence, the angular distribution of this decay cannot be measured. In this work, we construct a {\it measurable} angular distribution by considering the subsequent decay $\tau^- \to \pi^- \nu_\tau$. The full cascade decay is $B_c^- \to J/\psi (\to \mu^+ \mu^-)\tau^- (\to \pi^- \nu_\tau)\bar{\nu}_\tau$, in which the three-momenta $\boldsymbol{p}_{\mu^+}$, $\boldsymbol{p}_{\mu^-}$, and $\boldsymbol{p}_{\pi^-}$ can be measured. The five-fold differential angular distribution containing all Lorentz structures of the new physics (NP) effective operators can be written in terms of twelve angular observables $\mathcal{I}_i (q^2, E_\pi)$. Integrating over the energy of pion $E_\pi$, we construct twelve normalized angular observables $\widehat{\mathcal{I}}_i(q^2)$ and two lepton-flavor-universality ratios $R(P_{L,T}^{J/\psi})(q^2)$. Based on the $B_c \to J/\psi$ form factors calculated by the latest lattice QCD and sum rule, we predict the $q^2$ distribution of all $\widehat{\mathcal{I}}_i$ and $R(P_{L,T}^{J/\psi})$ both within the Standard Model and in eight NP benchmark points. We find that the benchmark BP2 (corresponding to the hypothesis of tensor operator) has the greatest effect on all $\widehat{\mathcal{I}}_{i}$ and $R(P_{L,T}^{J/\psi})$, except $\widehat{\mathcal{I}}_{5}$. The ratios $R(P_{L,T}^{J/\psi})$ are more sensitive to the NP with pseudo-scalar operators than the $\widehat{\mathcal{I}}_{i}$. Finally, we discuss the symmetries in the angular observables and present a model-independent method to determine the existence of tensor operators. |
hep-ph/0303125 | Jacques C. R. Bloch | J.C.R. Bloch | Two-loop Improved Truncation of the Ghost-Gluon Dyson-Schwinger
Equations: Multiplicatively Renormalizable Propagators and Nonperturbative
Running Coupling | 41 pages, LateX; minor corrections; accepted for publication in
Few-Body Systems | Few Body Syst.33:111-152,2003 | 10.1007/s00601-003-0013-3 | null | hep-ph hep-lat hep-th nucl-th | null | The coupled Dyson-Schwinger equations for the gluon and ghost propagators are
investigated in the Landau gauge using a two-loop improved truncation that
preserves the multiplicative renormalizability of the propagators. In this
truncation all diagrams contribute to the leading order infrared analysis. The
infrared contributions of the nonperturbative two-loop diagrams to the gluon
vacuum polarization are computed analytically, and this reveals that infrared
power behaved propagator solutions only exist when the squint diagram
contribution is taken into account. For small momenta the gluon and ghost
dressing functions behave respectively like (p^2)^{2\kappa} and
(p^2)^{-\kappa}, and the running coupling exhibits a fixed point. The values of
the infrared exponent and fixed point depend on the precise details of the
truncation. The coupled ghost-gluon system is solved numerically for all
momenta, and the solutions have infrared behaviors consistent with the
predictions of the infrared analysis. For truncation parameters chosen such
that \kappa=0.5, the two-loop improved truncation is able to produce solutions
for the propagators and running coupling which are in very good agreement with
recent lattice simulations.
| [
{
"created": "Fri, 14 Mar 2003 16:56:44 GMT",
"version": "v1"
},
{
"created": "Thu, 4 Sep 2003 15:50:26 GMT",
"version": "v2"
}
] | 2009-01-14 | [
[
"Bloch",
"J. C. R.",
""
]
] | The coupled Dyson-Schwinger equations for the gluon and ghost propagators are investigated in the Landau gauge using a two-loop improved truncation that preserves the multiplicative renormalizability of the propagators. In this truncation all diagrams contribute to the leading order infrared analysis. The infrared contributions of the nonperturbative two-loop diagrams to the gluon vacuum polarization are computed analytically, and this reveals that infrared power behaved propagator solutions only exist when the squint diagram contribution is taken into account. For small momenta the gluon and ghost dressing functions behave respectively like (p^2)^{2\kappa} and (p^2)^{-\kappa}, and the running coupling exhibits a fixed point. The values of the infrared exponent and fixed point depend on the precise details of the truncation. The coupled ghost-gluon system is solved numerically for all momenta, and the solutions have infrared behaviors consistent with the predictions of the infrared analysis. For truncation parameters chosen such that \kappa=0.5, the two-loop improved truncation is able to produce solutions for the propagators and running coupling which are in very good agreement with recent lattice simulations. |
hep-ph/9802260 | null | Hidenaga Yamagishi and Ismail Zahed | Two Topics in Chiral Effective Lagrangians | 7 pages | null | null | null | hep-ph | null | In the absence of nucleons, we use partial wave unitarity, to show that the
chiral expansion parameter must be close to $p^2/4\pi f_{\pi}^2$ rather than
$p^2/16\pi^2 f_{\pi}^2$ as previously suggested, where $p$ is a typical pion
momentum and $f_{\pi}$ the pion decay constant. When nucleons are included, we
apply the Tani-Foldy-Wouthuysen (TFW) transformation to the pion-nucleon
effective Lagrangian to obtain an expansion in powers of $1/m_N$ (inverse
nucleon mass). The results are presented up to order ${\cal O} (1/m_N^3)$,
corresponding to ${\cal O} (p^4)$ in the momentum. In this case partial
wave-unitarity is also lost in about the same range of momenta.
| [
{
"created": "Fri, 6 Feb 1998 00:50:26 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Yamagishi",
"Hidenaga",
""
],
[
"Zahed",
"Ismail",
""
]
] | In the absence of nucleons, we use partial wave unitarity, to show that the chiral expansion parameter must be close to $p^2/4\pi f_{\pi}^2$ rather than $p^2/16\pi^2 f_{\pi}^2$ as previously suggested, where $p$ is a typical pion momentum and $f_{\pi}$ the pion decay constant. When nucleons are included, we apply the Tani-Foldy-Wouthuysen (TFW) transformation to the pion-nucleon effective Lagrangian to obtain an expansion in powers of $1/m_N$ (inverse nucleon mass). The results are presented up to order ${\cal O} (1/m_N^3)$, corresponding to ${\cal O} (p^4)$ in the momentum. In this case partial wave-unitarity is also lost in about the same range of momenta. |
1708.00736 | Ho-Meoyng Choi | Ho-Meoyng Choi (1), Hui-Young Ryu (2) and Chueng-Ryong Ji (3) ((1)
Kyungpook National Univ., (2) Pusan National Univ., (3) North Carolina State
Univ.) | Spacelike and timelike form factors for the
$(\pi^0,\eta,\eta')\to\gamma^*\gamma$ transitions in the light-front quark
model | 13 pages, 7 figures, changed the title and corrected typo | Phys. Rev. D 96, 056008 (2017) | 10.1103/PhysRevD.96.056008 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the $(\pi^0,\eta,\eta')\to\gamma^*\gamma$ transitions both for
the spacelike region and the timelike region using the light-front quark model
(LFQM). In particular, we present the new direct method to explore the timelike
region without resorting to mere analytic continuation from the spacelike
region to the timelike region. Our direct calculation in timelike region shows
the complete agreement not only with the analytic continuation result from the
spacelike region but also with the result from the dispersion relation between
the real and imaginary parts of the form factor. For the low energy regime, we
compare our LFQM results of the transition form factors (TFFs) for the low
timelike momentum transfer region and the slope parameters at $q^2=0$ with the
recent experimental data from the Dalitz decays of $(\pi^0,\eta,\eta')$. For
the high energy regime, we incorporate the QCD factorization in our LFQM to
examine the asymptotic behavior of TFFs both for the spacelike region and the
timelike region. We compare our results with the available experimental data.
| [
{
"created": "Wed, 2 Aug 2017 13:28:15 GMT",
"version": "v1"
},
{
"created": "Fri, 4 Aug 2017 02:01:40 GMT",
"version": "v2"
},
{
"created": "Mon, 21 Aug 2017 19:36:14 GMT",
"version": "v3"
},
{
"created": "Fri, 15 Sep 2017 15:52:44 GMT",
"version": "v4"
}
] | 2017-09-20 | [
[
"Choi",
"Ho-Meoyng",
""
],
[
"Ryu",
"Hui-Young",
""
],
[
"Ji",
"Chueng-Ryong",
""
]
] | We investigate the $(\pi^0,\eta,\eta')\to\gamma^*\gamma$ transitions both for the spacelike region and the timelike region using the light-front quark model (LFQM). In particular, we present the new direct method to explore the timelike region without resorting to mere analytic continuation from the spacelike region to the timelike region. Our direct calculation in timelike region shows the complete agreement not only with the analytic continuation result from the spacelike region but also with the result from the dispersion relation between the real and imaginary parts of the form factor. For the low energy regime, we compare our LFQM results of the transition form factors (TFFs) for the low timelike momentum transfer region and the slope parameters at $q^2=0$ with the recent experimental data from the Dalitz decays of $(\pi^0,\eta,\eta')$. For the high energy regime, we incorporate the QCD factorization in our LFQM to examine the asymptotic behavior of TFFs both for the spacelike region and the timelike region. We compare our results with the available experimental data. |
hep-ph/0112198 | Holger Gies | Holger Gies (CERN), Kurt Langfeld (Tubingen U.) | Loops and loop clouds - a numerical approach to the worldline formalism
in QED - | 11 pages, 5 figures, talk given by H.G. at the Fifth Workshop on
Quantum Field Theory under the Influence of External Conditions, Leipzig,
Germany, September, 2001 | Int.J.Mod.Phys. A17 (2002) 966-978 | 10.1142/S0217751X02010388 | CERN-TH-2001-368 | hep-ph | null | A numerical technique for calculating effective actions of electromagnetic
backgrounds is proposed, which is based on the string-inspired worldline
formalism. As examples, we consider scalar electrodynamics in three and four
dimensions to one-loop order. Beyond the constant-magnetic-field case, we
analyze a step-function-like magnetic field exhibiting a nonlocal and
nonperturbative phenomenon: ``magnetic-field diffusion''. Finally,
generalizations to fermionic loops and systems at finite temperature are
discussed.
| [
{
"created": "Fri, 14 Dec 2001 11:02:51 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Gies",
"Holger",
"",
"CERN"
],
[
"Langfeld",
"Kurt",
"",
"Tubingen U."
]
] | A numerical technique for calculating effective actions of electromagnetic backgrounds is proposed, which is based on the string-inspired worldline formalism. As examples, we consider scalar electrodynamics in three and four dimensions to one-loop order. Beyond the constant-magnetic-field case, we analyze a step-function-like magnetic field exhibiting a nonlocal and nonperturbative phenomenon: ``magnetic-field diffusion''. Finally, generalizations to fermionic loops and systems at finite temperature are discussed. |
hep-ph/0201249 | Volker Drollinger | V. Drollinger, T. Muller, D. Denegri | Prospects for Higgs Boson Searches in the Channel WH -> lnbb | 8 pages, 8 figures | null | null | CMS NOTE 2002/006 | hep-ph | null | We present a method how to detect the WH -> lnbb in the high luminosity LHC
environment with the CMS detector. This study is performed with fast detector
response simulation including high luminosity event pile up. The main aspects
of reconstruction are pile up jet rejection, identification of b-jets and
improvement of Higgs mass resolution.
The detection potential in the SM for m(H) < 130 GeV and in the MSSM is only
encouraging for high integrated luminosity. Nevertheless it is possible to
extract important Higgs parameters which are useful to elucidate the nature of
the Higgs sector. In combination with other channels, this channel provides
valuable information on Higgs boson couplings.
| [
{
"created": "Sat, 26 Jan 2002 20:29:48 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Drollinger",
"V.",
""
],
[
"Muller",
"T.",
""
],
[
"Denegri",
"D.",
""
]
] | We present a method how to detect the WH -> lnbb in the high luminosity LHC environment with the CMS detector. This study is performed with fast detector response simulation including high luminosity event pile up. The main aspects of reconstruction are pile up jet rejection, identification of b-jets and improvement of Higgs mass resolution. The detection potential in the SM for m(H) < 130 GeV and in the MSSM is only encouraging for high integrated luminosity. Nevertheless it is possible to extract important Higgs parameters which are useful to elucidate the nature of the Higgs sector. In combination with other channels, this channel provides valuable information on Higgs boson couplings. |
hep-ph/0401021 | Eugene Levin | E. ~Gotsman, M. ~Kozlov, E. ~Levin, U. Maor and E. ~Naftali (Tel Aviv
U.) | Towards a New Global QCD Analysis: Solution to the Non-Linear Equation
at Arbitrary Impact Parameter | 26 pages with 19 figures in eps.files | Nucl.Phys. A742 (2004) 55-79 | 10.1016/j.nuclphysa.2004.05.018 | TAUP 2757/2004 | hep-ph | null | A numerical solution is presented for the non-linear evolution equation that
governs the dynamics of high parton density QCD. It is shown that thesolution
falls off as $e^{-b/R}$ at large values of the impact parameter $b$. The
power-like tail of the amplitude appears in impact parameter distributions only
after the inclusion of dipoles of size larger than the target, a configuration
for which the non-linear equation is not valid. The value, energy and impact
parameterof the saturation scale $Q_s(y=\ln(1/x),b)$) are calculated both for
fixed and running QCD coupling cases. It is shown that the solution exhibits
geometrical scaling behaviour. The radius of interaction increases as the
rapidity in accordance with the Froissart theorem. The solution we obtain
differs from previous attempts, where an anzatz for $b$ behaviour was made. The
solutions for running and fixed $\as$ differ. For running $\as$ we obtain a
larger radius of interaction (approximately twice as large), a steeper rapidity
dependence, and a larger value of the saturation scale.
| [
{
"created": "Tue, 6 Jan 2004 11:05:41 GMT",
"version": "v1"
},
{
"created": "Wed, 7 Jan 2004 07:24:42 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"~Gotsman",
"E.",
"",
"Tel Aviv\n U."
],
[
"~Kozlov",
"M.",
"",
"Tel Aviv\n U."
],
[
"~Levin",
"E.",
"",
"Tel Aviv\n U."
],
[
"Maor",
"U.",
"",
"Tel Aviv\n U."
],
[
"~Naftali",
"E.",
"",
"Tel Aviv\n U."
]
] | A numerical solution is presented for the non-linear evolution equation that governs the dynamics of high parton density QCD. It is shown that thesolution falls off as $e^{-b/R}$ at large values of the impact parameter $b$. The power-like tail of the amplitude appears in impact parameter distributions only after the inclusion of dipoles of size larger than the target, a configuration for which the non-linear equation is not valid. The value, energy and impact parameterof the saturation scale $Q_s(y=\ln(1/x),b)$) are calculated both for fixed and running QCD coupling cases. It is shown that the solution exhibits geometrical scaling behaviour. The radius of interaction increases as the rapidity in accordance with the Froissart theorem. The solution we obtain differs from previous attempts, where an anzatz for $b$ behaviour was made. The solutions for running and fixed $\as$ differ. For running $\as$ we obtain a larger radius of interaction (approximately twice as large), a steeper rapidity dependence, and a larger value of the saturation scale. |
0811.0563 | Stephan Narison | Stephan Narison | Light scalar mesons in QCD | 6 pages, Talk given at QCD 08 (7-12th july, Montpellier) and
Scientific part of the invited talk for a tribute to Paco Yndurain at
Confinement8 (3-7th september, Mainz) | Nucl.Phys.Proc.Suppl.186:306-311,2009 | 10.1016/j.nuclphysbps.2008.12.069 | null | hep-ph hep-ex hep-lat nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I present a mini-review of the masses and couplings of the bare (unmixed)
light scalar mesons : $\bar qq, (\overline{qq})(qq), (\bar qq)(\bar qq), gg$
from QCD spectral sum rules (QSSR) and low-energy theorems (LET) which we
compare with recent lattice calculations when available. Some unbiased comments
on the different scenarios are given. The possiblity for the $\sigma (0.6)$ to
be mostly a gluonium/glueball with a huge violation of the OZI rule in its
decay is discussed. This review complements and updates the ones presented
earlier [1]. Despite some progresses, the internal structure of the light
scalar mesons remain puzzling, and some further efforts are required. It will
be more fun at LHC if the Higgs of the Standard Model is a $\sigma$-like
resonance.
| [
{
"created": "Tue, 4 Nov 2008 18:23:18 GMT",
"version": "v1"
}
] | 2009-05-06 | [
[
"Narison",
"Stephan",
""
]
] | I present a mini-review of the masses and couplings of the bare (unmixed) light scalar mesons : $\bar qq, (\overline{qq})(qq), (\bar qq)(\bar qq), gg$ from QCD spectral sum rules (QSSR) and low-energy theorems (LET) which we compare with recent lattice calculations when available. Some unbiased comments on the different scenarios are given. The possiblity for the $\sigma (0.6)$ to be mostly a gluonium/glueball with a huge violation of the OZI rule in its decay is discussed. This review complements and updates the ones presented earlier [1]. Despite some progresses, the internal structure of the light scalar mesons remain puzzling, and some further efforts are required. It will be more fun at LHC if the Higgs of the Standard Model is a $\sigma$-like resonance. |
0807.0011 | Antonio Pineda | Jorge Mondejar and Antonio Pineda | Breakdown of the operator product expansion in the 't Hooft model | 4 pages | Phys.Rev.Lett.101:152002,2008 | 10.1103/PhysRevLett.101.152002 | null | hep-ph hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider deep inelastic scattering in the 't Hooft model. Being solvable,
this model allows us to directly compute the moments associated with the cross
section at next-to-leading order in the 1/Q^2 expansion. We perform the same
computation using the operator product expansion. We find that all the terms
match in both computations except for one in the hadronic side, which is
proportional to a non-local operator. The basics of the result suggest that a
similar phenomenon may occur in four dimensions in the large N_c limit.
| [
{
"created": "Mon, 30 Jun 2008 20:31:31 GMT",
"version": "v1"
},
{
"created": "Thu, 2 Oct 2008 19:09:38 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Mondejar",
"Jorge",
""
],
[
"Pineda",
"Antonio",
""
]
] | We consider deep inelastic scattering in the 't Hooft model. Being solvable, this model allows us to directly compute the moments associated with the cross section at next-to-leading order in the 1/Q^2 expansion. We perform the same computation using the operator product expansion. We find that all the terms match in both computations except for one in the hadronic side, which is proportional to a non-local operator. The basics of the result suggest that a similar phenomenon may occur in four dimensions in the large N_c limit. |
hep-ph/9502227 | Richard Lebed | Elizabeth Jenkins and Richard F. Lebed | Baryon Mass Splittings in the 1/N_c Expansion | 17 pages, LaTeX | Phys.Rev.D52:282-294,1995 | 10.1103/PhysRevD.52.282 | UCSD/PTH 95-01 | hep-ph | null | The $I=0,1,2,3$ mass splittings of the spin-$1/2$ octet and spin-$3/2$
decuplet baryons are analyzed in the $1/\N$ expansion combined with
perturbative flavor breaking. We show there is considerable experimental
evidence that the baryon masses satisfy the hierarchy predicted by this
expansion. Since flavor symmetry-breaking suppression factors alone are not
sufficient to describe the observed hierarchy, we conclude that there is firm
evidence for the $1/\N$ expansion in the baryon masses. Our analysis differs
from non-relativistic $SU(6)$.
| [
{
"created": "Mon, 6 Feb 1995 00:31:14 GMT",
"version": "v1"
}
] | 2016-09-01 | [
[
"Jenkins",
"Elizabeth",
""
],
[
"Lebed",
"Richard F.",
""
]
] | The $I=0,1,2,3$ mass splittings of the spin-$1/2$ octet and spin-$3/2$ decuplet baryons are analyzed in the $1/\N$ expansion combined with perturbative flavor breaking. We show there is considerable experimental evidence that the baryon masses satisfy the hierarchy predicted by this expansion. Since flavor symmetry-breaking suppression factors alone are not sufficient to describe the observed hierarchy, we conclude that there is firm evidence for the $1/\N$ expansion in the baryon masses. Our analysis differs from non-relativistic $SU(6)$. |
1711.11541 | Parsa Hossein Ghorbani | Parsa Hossein Ghorbani | Electroweak Phase Transition in Scale Invariant Standard Model | 6 pages, 4 figures, to be published in PRD | Phys. Rev. D 98, 115016 (2018) | 10.1103/PhysRevD.98.115016 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In an extension to the scale invariant standard model by two real singlet
scalars $s$ and $s'$ in addition to the Higgs field, we investigate the strong
first-order electroweak phase transition as a requirement for baryogenesis.
This is the minimal extension to the scale invariant standard model with two
extra degrees of freedom that possesses the physical Higgs mass of $125$ GeV.
The scalar $s'$ being stable because of the $\mathbb Z_2$ discrete symmetry is
taken as the dark matter candidate. We then show that the electroweak phase
transition is strongly first-order, the dark matter relic density takes the
desired value $\Omega_{\text{DM}}h^2 \sim 0.11$, and the constraints from
direct detection experiments are respected only if $m_{s'}\equiv m_{\text{DM}}
\gtrsim 4.5$ TeV. The model also puts a lower bound on the scalon mass, $m_s
\gtrsim 200$ GeV.
| [
{
"created": "Thu, 30 Nov 2017 18:00:51 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Dec 2017 14:35:05 GMT",
"version": "v2"
},
{
"created": "Thu, 14 Jun 2018 14:29:20 GMT",
"version": "v3"
},
{
"created": "Tue, 4 Dec 2018 18:02:36 GMT",
"version": "v4"
}
] | 2018-12-19 | [
[
"Ghorbani",
"Parsa Hossein",
""
]
] | In an extension to the scale invariant standard model by two real singlet scalars $s$ and $s'$ in addition to the Higgs field, we investigate the strong first-order electroweak phase transition as a requirement for baryogenesis. This is the minimal extension to the scale invariant standard model with two extra degrees of freedom that possesses the physical Higgs mass of $125$ GeV. The scalar $s'$ being stable because of the $\mathbb Z_2$ discrete symmetry is taken as the dark matter candidate. We then show that the electroweak phase transition is strongly first-order, the dark matter relic density takes the desired value $\Omega_{\text{DM}}h^2 \sim 0.11$, and the constraints from direct detection experiments are respected only if $m_{s'}\equiv m_{\text{DM}} \gtrsim 4.5$ TeV. The model also puts a lower bound on the scalon mass, $m_s \gtrsim 200$ GeV. |
0801.3441 | Feng Yuan | Feng Yuan | Collins Asymmetry at Hadron Colliders | 23 pages, 6 figures | Phys.Rev.D77:074019,2008 | 10.1103/PhysRevD.77.074019 | RBRC-718, LBNL-63750 | hep-ph | null | We study the Collins effect in the azimuthal asymmetric distribution of
hadrons inside a high energy jet in the single transverse polarized proton
proton scattering. From the detailed analysis of one-gluon and two-gluon
exchange diagrams contributions, the Collins function is found the same as that
in the semi-inclusive deep inelastic scattering and e^+e^- annihilations. The
eikonal propagators in these diagrams do not contribute to the phase needed for
the Collins-type single spin asymmetry, and the universality is derived as a
result of the Ward identity. We argue that this conclusion depends on the
momentum flow of the exchanged gluon and the kinematic constraints in the
fragmentation process, and is generic and model-independent.
| [
{
"created": "Tue, 22 Jan 2008 18:45:51 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Yuan",
"Feng",
""
]
] | We study the Collins effect in the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering. From the detailed analysis of one-gluon and two-gluon exchange diagrams contributions, the Collins function is found the same as that in the semi-inclusive deep inelastic scattering and e^+e^- annihilations. The eikonal propagators in these diagrams do not contribute to the phase needed for the Collins-type single spin asymmetry, and the universality is derived as a result of the Ward identity. We argue that this conclusion depends on the momentum flow of the exchanged gluon and the kinematic constraints in the fragmentation process, and is generic and model-independent. |
hep-ph/9401295 | Dr Tim Stelzer | K. Hagiwara, M. Tanaka and T. Stelzer | Singe Top Production at LEP 200 | 7 pages, 4 postscript figures | Phys.Lett.B325:521-525,1994 | 10.1016/0370-2693(94)90050-7 | KEK-TH-384 | hep-ph | null | We present exact tree level cross sections for the single top production
process $e^- e^+ \rightarrow e^- \bar{\nu}_e t \bar{b} $ at LEP~200. The
results reproduce roughly those obtained earlier by using the equivalent real
photon approximation and we confirm the observation that detecting a top
heavier than half the c.m.~energy is not feasible at LEP~200. The calculation
has been performed by a new automatic Feynman amplitude generator MadGraph
which produces HELAS code for the helicity amplitudes.
| [
{
"created": "Thu, 20 Jan 1994 15:39:07 GMT",
"version": "v1"
}
] | 2009-09-25 | [
[
"Hagiwara",
"K.",
""
],
[
"Tanaka",
"M.",
""
],
[
"Stelzer",
"T.",
""
]
] | We present exact tree level cross sections for the single top production process $e^- e^+ \rightarrow e^- \bar{\nu}_e t \bar{b} $ at LEP~200. The results reproduce roughly those obtained earlier by using the equivalent real photon approximation and we confirm the observation that detecting a top heavier than half the c.m.~energy is not feasible at LEP~200. The calculation has been performed by a new automatic Feynman amplitude generator MadGraph which produces HELAS code for the helicity amplitudes. |
1910.02082 | Philip Harris | Philip Coleman Harris, Dylan Sheldon Rankin, Cristina Mantilla Suarez | An approach to constraining the Higgs width at the LHC and HL-LHC | 27 pages, 12 figures, 1 appendix | null | null | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Despite the discovery of the Higgs boson decay in five separate channels many
parameters of the Higgs boson remain largely unconstrained. In this paper, we
present a new approach to constraining the Higgs total width by requiring the
Higgs to be resolved as a single high p$_T$ jet and measuring the inclusive
Higgs boson cross section. To measure the inclusive Higgs boson cross section,
we rely on new approaches from machine learning and a modified jet
reconstruction. This approach is found to be complementary to the existing
off-shell width measurement and, with the full HL-LHC luminosity, is capable of
yielding similar sensitivity to the off-shell projections. We outline the
theoretical and experimental limitations and present a path towards making this
approach a truly model-independent measurement of the Higgs boson total width.
| [
{
"created": "Fri, 4 Oct 2019 18:00:01 GMT",
"version": "v1"
}
] | 2019-10-08 | [
[
"Harris",
"Philip Coleman",
""
],
[
"Rankin",
"Dylan Sheldon",
""
],
[
"Suarez",
"Cristina Mantilla",
""
]
] | Despite the discovery of the Higgs boson decay in five separate channels many parameters of the Higgs boson remain largely unconstrained. In this paper, we present a new approach to constraining the Higgs total width by requiring the Higgs to be resolved as a single high p$_T$ jet and measuring the inclusive Higgs boson cross section. To measure the inclusive Higgs boson cross section, we rely on new approaches from machine learning and a modified jet reconstruction. This approach is found to be complementary to the existing off-shell width measurement and, with the full HL-LHC luminosity, is capable of yielding similar sensitivity to the off-shell projections. We outline the theoretical and experimental limitations and present a path towards making this approach a truly model-independent measurement of the Higgs boson total width. |
1510.00344 | Arman Esmaili | Arman Esmaili and Alexei Yu. Smirnov | Discrete symmetries and mixing of Dirac neutrinos | 17 pages, 1 figure; v2: references added, one section added and
discussion improved | Phys. Rev. D 92, 093012 (2015) | 10.1103/PhysRevD.92.093012 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study mixing of the Dirac neutrinos in the residual symmetries approach.
The key difference from the Majorana case is that the Dirac mass matrix may
have larger symmetries: $G_\nu=\mathbf{Z}_{n}$ with $n\geq3$. The symmetry
group relations have been generalized to the case of Dirac neutrinos. Using
them we have found all new relations between mixing parameters and
corresponding symmetry assignments which are in agreement with the present
data. The viable relations exist only for the charged lepton residual symmetry
$G_{\ell} = \mathbf{Z}_{2}$. The relations involve elements of the rows of the
PMNS matrix and lead to precise predictions of the 2-3 mixing angle and certain
ranges of the CP violation phase. For larger symmetries $G_{\ell}$, an
agreement with data can be achieved if $\sim10\%$ corrections related to
breaking of $G_{\ell}$ and $G_\nu$ are included.
| [
{
"created": "Thu, 1 Oct 2015 18:02:58 GMT",
"version": "v1"
},
{
"created": "Fri, 16 Oct 2015 18:42:54 GMT",
"version": "v2"
}
] | 2015-12-02 | [
[
"Esmaili",
"Arman",
""
],
[
"Smirnov",
"Alexei Yu.",
""
]
] | We study mixing of the Dirac neutrinos in the residual symmetries approach. The key difference from the Majorana case is that the Dirac mass matrix may have larger symmetries: $G_\nu=\mathbf{Z}_{n}$ with $n\geq3$. The symmetry group relations have been generalized to the case of Dirac neutrinos. Using them we have found all new relations between mixing parameters and corresponding symmetry assignments which are in agreement with the present data. The viable relations exist only for the charged lepton residual symmetry $G_{\ell} = \mathbf{Z}_{2}$. The relations involve elements of the rows of the PMNS matrix and lead to precise predictions of the 2-3 mixing angle and certain ranges of the CP violation phase. For larger symmetries $G_{\ell}$, an agreement with data can be achieved if $\sim10\%$ corrections related to breaking of $G_{\ell}$ and $G_\nu$ are included. |
hep-ph/0101250 | Mario E. Gomez | Daniel F. Carvalho, Mario E. Gomez, Shaaban Khalil | Lepton-Flavor Violation with Non-universal Soft Terms | 15 pages, 6 figures minor changes | JHEP 0107:001,2001 | 10.1088/1126-6708/2001/07/001 | null | hep-ph | null | We study the lepton-flavor violation processes tau ->mu gamma and mu->e gamma
in two different examples of models with non-universal soft breaking terms
derived from strings. We show that the predictions are quite different from
those of universal scenarios. Non-universal A-terms provide an interesting
framework to enhance the supersymmetric contributions to CP violation effects.
We observe that in the case of the lepton-flavor violation we study, the
non-universality of the scalar masses enhances the branching ratios more
significantly than the non-universality of the A-terms. We find that the
current experimental bounds on these processes restrict both the parameter
space of the models and the texture of the Yukawa couplings which predicts the
lepton masses, providing at the same time an interesting experimental test for
physics beyond the Standard Model.
| [
{
"created": "Mon, 22 Jan 2001 19:40:54 GMT",
"version": "v1"
},
{
"created": "Tue, 3 Apr 2001 22:22:22 GMT",
"version": "v2"
},
{
"created": "Wed, 9 May 2001 19:44:49 GMT",
"version": "v3"
}
] | 2010-02-03 | [
[
"Carvalho",
"Daniel F.",
""
],
[
"Gomez",
"Mario E.",
""
],
[
"Khalil",
"Shaaban",
""
]
] | We study the lepton-flavor violation processes tau ->mu gamma and mu->e gamma in two different examples of models with non-universal soft breaking terms derived from strings. We show that the predictions are quite different from those of universal scenarios. Non-universal A-terms provide an interesting framework to enhance the supersymmetric contributions to CP violation effects. We observe that in the case of the lepton-flavor violation we study, the non-universality of the scalar masses enhances the branching ratios more significantly than the non-universality of the A-terms. We find that the current experimental bounds on these processes restrict both the parameter space of the models and the texture of the Yukawa couplings which predicts the lepton masses, providing at the same time an interesting experimental test for physics beyond the Standard Model. |
1407.4624 | Wolfgang Lucha | Wolfgang Lucha, Franz F. Sch\"oberl | Semirelativistic Bound-State Equations: Trivial Considerations | 5 pages, contributed to "QCD@Work 2014 - International Workshop on
Quantum Chromodynamics: Theory and Experiment" (16 - 19 June 2014,
Giovinazzo, Bari, Italy) | EPJ Web of Conferences 80 (2014) 00049 | 10.1051/epjconf/20148000049 | HEPHY-PUB 934/14 | hep-ph math-ph math.MP nucl-th quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Observing renewed interest in long-standing (semi-) relativistic descriptions
of bound states, we would like to make a few comments on the eigenvalue problem
posed by the spinless Salpeter equation and, illustrated by the examples of the
nonsingular Woods-Saxon potential and the singular Hulth\'en potential, recall
elementary tools that practitioners looking for analytic albeit approximate
solutions might find useful in their quest.
| [
{
"created": "Thu, 17 Jul 2014 10:38:20 GMT",
"version": "v1"
}
] | 2014-11-26 | [
[
"Lucha",
"Wolfgang",
""
],
[
"Schöberl",
"Franz F.",
""
]
] | Observing renewed interest in long-standing (semi-) relativistic descriptions of bound states, we would like to make a few comments on the eigenvalue problem posed by the spinless Salpeter equation and, illustrated by the examples of the nonsingular Woods-Saxon potential and the singular Hulth\'en potential, recall elementary tools that practitioners looking for analytic albeit approximate solutions might find useful in their quest. |
2306.07325 | Rama Krishnan | R. Krishnan | Homogeneous linear intrinsic constraints in the stationary manifold of a
$G$-invariant potential | 25 pages which include 15 pages of appendix, 7 figures which include
4 figures in the appendix. A video presentation of this paper is available
here:
https://www.youtube.com/playlist?list=PLjRYJtC1E1HfEbur89bH3CT5BvMtO4FWK | null | null | null | hep-ph hep-th math-ph math.MP | http://creativecommons.org/licenses/by/4.0/ | Given a $G$-invariant potential $\mathcal{V}$ of a scalar multiplet
$\varphi$, there may exist a set of homogenous linear equations that constrain
the components of a stationary point of $\mathcal{V}$ independently of the
coefficients of the terms in $\mathcal{V}$. We call them homogeneous linear
intrinsic constraints (HLICs). HLICs in a stationary point manifest as HLICs in
the corresponding vacuum alignment of $\varphi$, which plays a central role in
predictive phenomenological models. We discover that a group $\tilde{H}$
generates HLICs if the terms in $\mathcal{V}$ satisfy a condition, which we
call the compatibility condition. In this paper, we also develop a procedure,
which involves splitting $\mathcal{V}$ into smaller parts, to establish the
existence of specific stationary points using arguments based on symmetries
without the need for explicitly extremizing the potential. Using this
procedure, we obtain $\tilde{H}$ as a direct product of the symmetry groups
associated with the various irreducible multiplets (irreps) in $\varphi$. This
results from considering the potentials of the irreps separately and verifying
if the cross terms are compatible with $\tilde{H}$.
| [
{
"created": "Mon, 12 Jun 2023 18:00:02 GMT",
"version": "v1"
},
{
"created": "Fri, 22 Sep 2023 10:41:38 GMT",
"version": "v2"
}
] | 2023-09-25 | [
[
"Krishnan",
"R.",
""
]
] | Given a $G$-invariant potential $\mathcal{V}$ of a scalar multiplet $\varphi$, there may exist a set of homogenous linear equations that constrain the components of a stationary point of $\mathcal{V}$ independently of the coefficients of the terms in $\mathcal{V}$. We call them homogeneous linear intrinsic constraints (HLICs). HLICs in a stationary point manifest as HLICs in the corresponding vacuum alignment of $\varphi$, which plays a central role in predictive phenomenological models. We discover that a group $\tilde{H}$ generates HLICs if the terms in $\mathcal{V}$ satisfy a condition, which we call the compatibility condition. In this paper, we also develop a procedure, which involves splitting $\mathcal{V}$ into smaller parts, to establish the existence of specific stationary points using arguments based on symmetries without the need for explicitly extremizing the potential. Using this procedure, we obtain $\tilde{H}$ as a direct product of the symmetry groups associated with the various irreducible multiplets (irreps) in $\varphi$. This results from considering the potentials of the irreps separately and verifying if the cross terms are compatible with $\tilde{H}$. |
0709.1505 | Michael Trott | Sonny Mantry, Michael Trott, Mark B. Wise | The Higgs Decay Width in Multi-Scalar Doublet Models | 18 pages, 3 figures V2: refs added | Phys.Rev.D77:013006,2008 | 10.1103/PhysRevD.77.013006 | null | hep-ph | null | We show that there are regions of parameter space in multi-scalar doublet
models where, in the first few hundred inverse femtobarns of data, the new
charged and neutral scalars are not directly observable at the LHC and yet the
Higgs decay rate to b bbar is changed significantly from its standard model
value. For a light Higgs with a mass less than 140 GeV, this can cause a large
change in the number of two photon and tau tau Higgs decay events expected at
the LHC compared to the minimal standard model. In the models we consider, the
principle of minimal flavor violation is used to suppress flavor changing
neutral currents. This paper emphasizes the importance of measuring the
properties of the Higgs boson at the LHC; for a range of parameters the model
considered has new physics at the TeV scale that is invisible, in the first few
hundred inverse femtobarns of integrated luminosity at the LHC, except
indirectly through the measurement of Higgs boson properties.
| [
{
"created": "Mon, 10 Sep 2007 23:04:14 GMT",
"version": "v1"
},
{
"created": "Fri, 28 Sep 2007 01:05:13 GMT",
"version": "v2"
},
{
"created": "Fri, 30 Nov 2007 23:47:53 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Mantry",
"Sonny",
""
],
[
"Trott",
"Michael",
""
],
[
"Wise",
"Mark B.",
""
]
] | We show that there are regions of parameter space in multi-scalar doublet models where, in the first few hundred inverse femtobarns of data, the new charged and neutral scalars are not directly observable at the LHC and yet the Higgs decay rate to b bbar is changed significantly from its standard model value. For a light Higgs with a mass less than 140 GeV, this can cause a large change in the number of two photon and tau tau Higgs decay events expected at the LHC compared to the minimal standard model. In the models we consider, the principle of minimal flavor violation is used to suppress flavor changing neutral currents. This paper emphasizes the importance of measuring the properties of the Higgs boson at the LHC; for a range of parameters the model considered has new physics at the TeV scale that is invisible, in the first few hundred inverse femtobarns of integrated luminosity at the LHC, except indirectly through the measurement of Higgs boson properties. |
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