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hep-ph/9703349
Tobias Hurth
Christoph Greub (DESY), Tobias Hurth (SUNY at Stony Brook)
Two-loop matching of the dipole operators for $b \to s \gamma$ and $b \to s gluon$
24 pages, latex, 6 figures included
Phys.Rev.D56:2934-2949,1997
10.1103/PhysRevD.56.2934
DESY 97-040, ITB-SB-97-18
hep-ph
null
The order $\alpha_s$ corrections to the Wilson coefficients of the dipole operators ($O_7,O_8$) at the matching scale $\mu =m_W$ are a crucial ingredient for a complete next- to-leading logarithmic calculation of the branching ratio for $b \to s \gamma$. Given the phenomenological relevance and the fact that this two-loop calculation has been done so far only by one group [1], we present a detailed re-calculation using a different method. Our results are in complete agreement with those in ref. [1].
[ { "created": "Tue, 18 Mar 1997 04:56:49 GMT", "version": "v1" } ]
2014-11-17
[ [ "Greub", "Christoph", "", "DESY" ], [ "Hurth", "Tobias", "", "SUNY at Stony Brook" ] ]
The order $\alpha_s$ corrections to the Wilson coefficients of the dipole operators ($O_7,O_8$) at the matching scale $\mu =m_W$ are a crucial ingredient for a complete next- to-leading logarithmic calculation of the branching ratio for $b \to s \gamma$. Given the phenomenological relevance and the fact that this two-loop calculation has been done so far only by one group [1], we present a detailed re-calculation using a different method. Our results are in complete agreement with those in ref. [1].
hep-ph/0012091
Boris Kopeliovich
B.Z. Kopeliovich (Heidelberg), T.L. Trueman (Brookhaven)
Polarized Proton Nucleus Scattering
Latex, 22 pages including 7 figures
Phys.Rev.D64:034004,2001
10.1103/PhysRevD.64.034004
null
hep-ph nucl-th
null
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
[ { "created": "Thu, 7 Dec 2000 22:46:53 GMT", "version": "v1" }, { "created": "Mon, 28 May 2001 18:12:29 GMT", "version": "v2" } ]
2010-11-19
[ [ "Kopeliovich", "B. Z.", "", "Heidelberg" ], [ "Trueman", "T. L.", "", "Brookhaven" ] ]
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
hep-ph/9705433
null
T. Csorgo (Columbia and KFKI RMKI) and J. Zimanyi (KFKI RMKI)
Analytic Solution of the Pion-Laser Model
LaTeX, ReVTeX 3.1, 7 pages, uses 1 eps figure and epsfig.sty (shortened version)
Phys.Rev.Lett. 80 (1998) 916-918
10.1103/PhysRevLett.80.916
null
hep-ph hep-th nucl-th physics.optics quant-ph
null
Brooding over bosons, wave packets and Bose - Einstein correlations, we find that a generalization of the pion-laser model for the case of overlapping wave-packets is analytically solvable with complete n-particle symmetrization. The effective radius parameter of the two-particle correlation function is reduced for low values and enlargened for high values of the mean momentum in the rare gas limiting case, as compared to the case when multi-particle symmetrization effects are neglected. These results explicitly depend on the multiplicity, providing a theoretical basis for event-by-event analysis of high energy heavy ion reactions.
[ { "created": "Mon, 26 May 1997 18:41:13 GMT", "version": "v1" }, { "created": "Tue, 1 Jul 1997 10:12:39 GMT", "version": "v2" } ]
2016-09-06
[ [ "Csorgo", "T.", "", "Columbia and KFKI RMKI" ], [ "Zimanyi", "J.", "", "KFKI RMKI" ] ]
Brooding over bosons, wave packets and Bose - Einstein correlations, we find that a generalization of the pion-laser model for the case of overlapping wave-packets is analytically solvable with complete n-particle symmetrization. The effective radius parameter of the two-particle correlation function is reduced for low values and enlargened for high values of the mean momentum in the rare gas limiting case, as compared to the case when multi-particle symmetrization effects are neglected. These results explicitly depend on the multiplicity, providing a theoretical basis for event-by-event analysis of high energy heavy ion reactions.
1704.08249
Andrew Larkoski
Kaustuv Datta and Andrew Larkoski
How Much Information is in a Jet?
14 pages + appendices, 10 figures; v2: JHEP version, updated neural network, included deeper network and boosted decision tree results
null
10.1007/JHEP06(2017)073
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Machine learning techniques are increasingly being applied toward data analyses at the Large Hadron Collider, especially with applications for discrimination of jets with different originating particles. Previous studies of the power of machine learning to jet physics has typically employed image recognition, natural language processing, or other algorithms that have been extensively developed in computer science. While these studies have demonstrated impressive discrimination power, often exceeding that of widely-used observables, they have been formulated in a non-constructive manner and it is not clear what additional information the machines are learning. In this paper, we study machine learning for jet physics constructively, expressing all of the information in a jet onto sets of observables that completely and minimally span N-body phase space. For concreteness, we study the application of machine learning for discrimination of boosted, hadronic decays of Z bosons from jets initiated by QCD processes. Our results demonstrate that the information in a jet that is useful for discrimination power of QCD jets from Z bosons is saturated by only considering observables that are sensitive to 4-body (8 dimensional) phase space.
[ { "created": "Wed, 26 Apr 2017 18:00:00 GMT", "version": "v1" }, { "created": "Wed, 7 Jun 2017 15:11:14 GMT", "version": "v2" } ]
2017-06-28
[ [ "Datta", "Kaustuv", "" ], [ "Larkoski", "Andrew", "" ] ]
Machine learning techniques are increasingly being applied toward data analyses at the Large Hadron Collider, especially with applications for discrimination of jets with different originating particles. Previous studies of the power of machine learning to jet physics has typically employed image recognition, natural language processing, or other algorithms that have been extensively developed in computer science. While these studies have demonstrated impressive discrimination power, often exceeding that of widely-used observables, they have been formulated in a non-constructive manner and it is not clear what additional information the machines are learning. In this paper, we study machine learning for jet physics constructively, expressing all of the information in a jet onto sets of observables that completely and minimally span N-body phase space. For concreteness, we study the application of machine learning for discrimination of boosted, hadronic decays of Z bosons from jets initiated by QCD processes. Our results demonstrate that the information in a jet that is useful for discrimination power of QCD jets from Z bosons is saturated by only considering observables that are sensitive to 4-body (8 dimensional) phase space.
1010.3588
Paul Archer
Paul R. Archer, Stephan J. Huber
Reducing Constraints in a Higher Dimensional Extension of the Randall and Sundrum Model
27 pages, 15 figures, v3: Additional comments in sections 1, 2 and 4. New appendix added. Five additional figures. References added
JHEP 1103:018,2011
10.1007/JHEP03(2011)018
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In order to investigate the phenomenological implications of warped spaces in more than five dimensions, we consider a $4+1+\delta$ dimensional extension to the Randall and Sundrum model in which the space is warped with respect to a single direction by the presence of an anisotropic bulk cosmological constant. The Einstein equations are solved, giving rise to a range of possible spaces in which the $\delta$ additional spaces are warped. Here we consider models in which the gauge fields are free to propagate into such spaces. After carrying out the Kaluza Klein (KK) decomposition of such fields it is found that the KK mass spectrum changes significantly depending on how the $\delta$ additional dimensions are warped. We proceed to compute the lower bound on the KK mass scale from electroweak observables for models with a bulk $SU(2)\times U(1)$ gauge symmetry and models with a bulk $SU(2)_R\times SU(2)_L\times U(1)$ gauge symmetry. It is found that in both cases the most favourable bounds are approximately $M_{KK}\gtrsim 2$ TeV, corresponding to a mass of the first gauge boson excitation of about 4-6 TeV. Hence additional warped dimensions offer a new way of reducing the constraints on the KK scale.
[ { "created": "Mon, 18 Oct 2010 13:12:39 GMT", "version": "v1" }, { "created": "Wed, 10 Nov 2010 11:53:54 GMT", "version": "v2" }, { "created": "Thu, 3 Feb 2011 15:06:25 GMT", "version": "v3" } ]
2015-03-17
[ [ "Archer", "Paul R.", "" ], [ "Huber", "Stephan J.", "" ] ]
In order to investigate the phenomenological implications of warped spaces in more than five dimensions, we consider a $4+1+\delta$ dimensional extension to the Randall and Sundrum model in which the space is warped with respect to a single direction by the presence of an anisotropic bulk cosmological constant. The Einstein equations are solved, giving rise to a range of possible spaces in which the $\delta$ additional spaces are warped. Here we consider models in which the gauge fields are free to propagate into such spaces. After carrying out the Kaluza Klein (KK) decomposition of such fields it is found that the KK mass spectrum changes significantly depending on how the $\delta$ additional dimensions are warped. We proceed to compute the lower bound on the KK mass scale from electroweak observables for models with a bulk $SU(2)\times U(1)$ gauge symmetry and models with a bulk $SU(2)_R\times SU(2)_L\times U(1)$ gauge symmetry. It is found that in both cases the most favourable bounds are approximately $M_{KK}\gtrsim 2$ TeV, corresponding to a mass of the first gauge boson excitation of about 4-6 TeV. Hence additional warped dimensions offer a new way of reducing the constraints on the KK scale.
2012.04599
Menglin Du Dr.
Meng-Lin Du, Feng-Kun Guo, Christoph Hanhart, Bastian Kubis, and Ulf-G. Mei{\ss}ner
Where is the lightest charmed scalar meson?
Note: Title slightly changed, version to appear in Phys. Rev. Lett.; 9 pages, 5 figures
Phys. Rev. Lett. 126, 192001 (2021)
10.1103/PhysRevLett.126.192001
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
The lightest charmed scalar meson is known as the $D_0^*(2300)$, which is one of the earliest new hadron resonances observed at modern $B$ factories. We show here that the parameters assigned to the lightest scalar $D$-meson are in conflict with the precise LHCb data of the decay $B^-\to D^+ \pi^- \pi^-$. On the contrary, these data can be well described by an unitarized chiral amplitude containing a much lighter charmed scalar meson, the $D_0^*(2100)$. We also extract the low-energy $S$-wave $D\pi$ phase of the decay $B^-\to D^+ \pi^- \pi^-$ from the data in a model-independent way, and show that its difference from the $D\pi$ scattering phase shift can be traced back to an intermediate $\rho^-$ exchange. Our work highlights that an analysis of data consistent with chiral symmetry, unitarity, and analyticity is mandatory in order to extract the properties of the ground-state scalar mesons in the singly heavy sector correctly, in analogy to the light scalar mesons $f_0(500)$ and $K_0^*(700)$.
[ { "created": "Tue, 8 Dec 2020 18:00:10 GMT", "version": "v1" }, { "created": "Tue, 4 May 2021 14:39:32 GMT", "version": "v2" } ]
2021-05-14
[ [ "Du", "Meng-Lin", "" ], [ "Guo", "Feng-Kun", "" ], [ "Hanhart", "Christoph", "" ], [ "Kubis", "Bastian", "" ], [ "Meißner", "Ulf-G.", "" ] ]
The lightest charmed scalar meson is known as the $D_0^*(2300)$, which is one of the earliest new hadron resonances observed at modern $B$ factories. We show here that the parameters assigned to the lightest scalar $D$-meson are in conflict with the precise LHCb data of the decay $B^-\to D^+ \pi^- \pi^-$. On the contrary, these data can be well described by an unitarized chiral amplitude containing a much lighter charmed scalar meson, the $D_0^*(2100)$. We also extract the low-energy $S$-wave $D\pi$ phase of the decay $B^-\to D^+ \pi^- \pi^-$ from the data in a model-independent way, and show that its difference from the $D\pi$ scattering phase shift can be traced back to an intermediate $\rho^-$ exchange. Our work highlights that an analysis of data consistent with chiral symmetry, unitarity, and analyticity is mandatory in order to extract the properties of the ground-state scalar mesons in the singly heavy sector correctly, in analogy to the light scalar mesons $f_0(500)$ and $K_0^*(700)$.
1110.0096
Marco Frasca
Marco Frasca
Low-energy limit of QCD at finite temperature
11 pages, 1 figure, contribution to the proceedings of the Eleventh Workshop on Non-Perturbative Quantum Chromodynamics, Paris, June 6-10, 2011
SLAC eConf C1106064, 27 (2011)
null
null
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We are able to show, in the low-energy limit of quantum chromodynamics, that the theory has a critical point. In this limit, QCD becomes a non-local Nambu-Jona-Lasinio model. The critical temperature is also obtained in agreement with lattice computations.
[ { "created": "Sat, 1 Oct 2011 12:32:31 GMT", "version": "v1" } ]
2012-01-26
[ [ "Frasca", "Marco", "" ] ]
We are able to show, in the low-energy limit of quantum chromodynamics, that the theory has a critical point. In this limit, QCD becomes a non-local Nambu-Jona-Lasinio model. The critical temperature is also obtained in agreement with lattice computations.
2206.14018
Nishat Fiza
Nishat Fiza, Nafis Rezwan Khan Chowdhury, Mehedi Masud
Investigating Lorentz Violation with the long baseline experiment P2O
Published in JHEP, 9 figures, 29 pages, DUNE-only results added, more simulation details included, conclusions unchanged
null
10.1007/JHEP01(2023)076
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
One of the basic propositions of quantum field theory is Lorentz invariance. The spontaneous breaking of Lorentz symmetry at a high energy scale can be studied at low energy extensions like the Standard model in a model-independent way through effective field theory (EFT). The present and future Long-baseline neutrino experiments can give a scope to observe such a Planck-suppressed physics of Lorentz invariance violation (LIV). A proposed long baseline experiment, Protvino to ORCA (dubbed "P2O") with a baseline of 2595 km, is expected to provide good sensitivities to unresolved issues, especially neutrino mass ordering. P2O can offer good statistics even with a moderate beam power and runtime, owing to the very large ($\sim 6$ Mt) detector volume at KM3NeT/ ORCA. Here we discuss in detail, how the individual LIV parameters affect neutrino oscillations at P2O and DUNE baselines at the level of probability and derive analytical expressions to understand interesting degeneracies and other features. We estimate $\Delta \chi^{2}$ sensitivities to the LIV parameters, analyzing their correlations among each other, and also with the standard oscillation parameters. We calculate these results for P2O alone and also carry out a combined analysis of P2O with DUNE. We point out crucial features in the sensitivity contours and explain them qualitatively with the help of the relevant probability expressions derived here. Finally, we estimate constraints on the individual LIV parameters at $95\%$ confidence level (C.L.) intervals stemming from the combined analysis of P2O and DUNE datasets and highlight the improvement over the existing constraints. We also find out that the additional degeneracy induced by the LIV parameter $a_{ee}$ around $-22 \times 10^{-23}$ GeV is lifted by the combined analysis at $95\%$ C.L.
[ { "created": "Tue, 28 Jun 2022 14:05:59 GMT", "version": "v1" }, { "created": "Mon, 16 Jan 2023 18:23:44 GMT", "version": "v2" } ]
2023-02-08
[ [ "Fiza", "Nishat", "" ], [ "Chowdhury", "Nafis Rezwan Khan", "" ], [ "Masud", "Mehedi", "" ] ]
One of the basic propositions of quantum field theory is Lorentz invariance. The spontaneous breaking of Lorentz symmetry at a high energy scale can be studied at low energy extensions like the Standard model in a model-independent way through effective field theory (EFT). The present and future Long-baseline neutrino experiments can give a scope to observe such a Planck-suppressed physics of Lorentz invariance violation (LIV). A proposed long baseline experiment, Protvino to ORCA (dubbed "P2O") with a baseline of 2595 km, is expected to provide good sensitivities to unresolved issues, especially neutrino mass ordering. P2O can offer good statistics even with a moderate beam power and runtime, owing to the very large ($\sim 6$ Mt) detector volume at KM3NeT/ ORCA. Here we discuss in detail, how the individual LIV parameters affect neutrino oscillations at P2O and DUNE baselines at the level of probability and derive analytical expressions to understand interesting degeneracies and other features. We estimate $\Delta \chi^{2}$ sensitivities to the LIV parameters, analyzing their correlations among each other, and also with the standard oscillation parameters. We calculate these results for P2O alone and also carry out a combined analysis of P2O with DUNE. We point out crucial features in the sensitivity contours and explain them qualitatively with the help of the relevant probability expressions derived here. Finally, we estimate constraints on the individual LIV parameters at $95\%$ confidence level (C.L.) intervals stemming from the combined analysis of P2O and DUNE datasets and highlight the improvement over the existing constraints. We also find out that the additional degeneracy induced by the LIV parameter $a_{ee}$ around $-22 \times 10^{-23}$ GeV is lifted by the combined analysis at $95\%$ C.L.
1701.08614
Xiao-Gang He
Min He, Xiao-Gang He, Cheng-Kai Huang
Dark Photon Search at A Circular $e^+e^-$ Collider
RevTex, 9 pages with five figures. Minor modifications added
null
10.1142/S0217751X1750138X
NCTS-PY1706
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One of the interesting portals linking a dark sector and the standard model (SM) is the kinetic mixing between the SM $U(1)_Y$ field with a new dark photon $A'$ from a $U(1)_{A'}$ gauge interaction. Stringent limits have been obtained for the kinetic mixing parameter $\epsilon$ through various processes. In this work, we study the possibility of searching for a dark photon interaction at a circular $e^+e^-$ collider through the process $e^+ e^-\to \gamma A^{\prime *} \to \gamma \mu^+\mu^-$. We find that the constraint on $\epsilon^2$ for dark photon mass in the few tens of GeV range, assuming that the $\mu^+\mu^-$ invariant mass can be measured to an accuracy of $0.5\%m_{A'}$, can be better than $3\times 10^{-6}$ for the proposed CEPC with a ten-year running at 3$\sigma$ (statistic) level, and better than $2\times 10^{-6}$ for FCC-ee with even just one-year running at $\sqrt{s} = 240$ GeV, better than the LHC and other facilities can do in a similar dark photon mass range. For FCC-ee, running at $\sqrt{s}=160$ GeV, the constraint can be even better.
[ { "created": "Mon, 30 Jan 2017 14:29:10 GMT", "version": "v1" }, { "created": "Sun, 12 Feb 2017 04:49:04 GMT", "version": "v2" }, { "created": "Thu, 23 Mar 2017 08:08:33 GMT", "version": "v3" } ]
2017-09-13
[ [ "He", "Min", "" ], [ "He", "Xiao-Gang", "" ], [ "Huang", "Cheng-Kai", "" ] ]
One of the interesting portals linking a dark sector and the standard model (SM) is the kinetic mixing between the SM $U(1)_Y$ field with a new dark photon $A'$ from a $U(1)_{A'}$ gauge interaction. Stringent limits have been obtained for the kinetic mixing parameter $\epsilon$ through various processes. In this work, we study the possibility of searching for a dark photon interaction at a circular $e^+e^-$ collider through the process $e^+ e^-\to \gamma A^{\prime *} \to \gamma \mu^+\mu^-$. We find that the constraint on $\epsilon^2$ for dark photon mass in the few tens of GeV range, assuming that the $\mu^+\mu^-$ invariant mass can be measured to an accuracy of $0.5\%m_{A'}$, can be better than $3\times 10^{-6}$ for the proposed CEPC with a ten-year running at 3$\sigma$ (statistic) level, and better than $2\times 10^{-6}$ for FCC-ee with even just one-year running at $\sqrt{s} = 240$ GeV, better than the LHC and other facilities can do in a similar dark photon mass range. For FCC-ee, running at $\sqrt{s}=160$ GeV, the constraint can be even better.
hep-ph/9505367
null
F.L. Braghin, D. Vautherin and A. Abada
Isovector response function of hot nuclear matter with Skyrme interactions
33 pages Email: braghin@ipncls.in2p3.fr
Phys.Rev.C52:2504,1995
10.1103/PhysRevC.52.2504
UNITU-THEP-7/1995 and IPNO/TH 95-11
hep-ph
null
We investigate the role of the effective nucleon-nucleon interaction in the description of giant dipole resonances in hot nuclei. For this purpose we calculate the response function of hot nuclear matter to a small isovector external perturbation using various effective Skyrme interactions. We find that for Skyrme forces with an effective mass close to unity an undamped zero sound mode occurs at zero temperature. This mode gives rise in finite nuclei (calculated via the Steinwedel-Jenssen model) to a resonance whose energy agrees with the observed value. We find that zero sound disappears at a temperature of a few MeV, leaving only a broad peak in the dipole strength. For Skyrme forces with a small value of the effective mass (0.4- 0.5), there is no zero sound at zero temperature but only a weak peak located too high in energy. The strength distribution in this case is nearly independent of temperature and shows small collective effects. The relevance of these results for the saturation of photon multiplicities observed in recent experiments is pointed out.
[ { "created": "Tue, 23 May 1995 17:27:08 GMT", "version": "v1" } ]
2008-11-26
[ [ "Braghin", "F. L.", "" ], [ "Vautherin", "D.", "" ], [ "Abada", "A.", "" ] ]
We investigate the role of the effective nucleon-nucleon interaction in the description of giant dipole resonances in hot nuclei. For this purpose we calculate the response function of hot nuclear matter to a small isovector external perturbation using various effective Skyrme interactions. We find that for Skyrme forces with an effective mass close to unity an undamped zero sound mode occurs at zero temperature. This mode gives rise in finite nuclei (calculated via the Steinwedel-Jenssen model) to a resonance whose energy agrees with the observed value. We find that zero sound disappears at a temperature of a few MeV, leaving only a broad peak in the dipole strength. For Skyrme forces with a small value of the effective mass (0.4- 0.5), there is no zero sound at zero temperature but only a weak peak located too high in energy. The strength distribution in this case is nearly independent of temperature and shows small collective effects. The relevance of these results for the saturation of photon multiplicities observed in recent experiments is pointed out.
hep-ph/0608035
Gintaras Duda
Gintaras Duda, Ann Kemper, Paolo Gondolo
Model Independent Form Factors for Spin Independent Neutralino-Nucleon Scattering from Elastic Electron Scattering Data
20 pages, 8 figures
JCAP 0704:012,2007
10.1088/1475-7516/2007/04/012
null
hep-ph
null
Theoretical calculations of neutralino-nucleon interaction rates with various nuclei are of great interest to direct dark matter searches such as CDMS, EDELWEISS, ZEPLIN, and other experiments since they are used to establish upper bounds on the WIMP-proton cross section. These interaction rates and cross sections are generally computed with standard, one or two parameter model-dependent nuclear form factors, which may not exactly mirror the actual form factor for the particular nucleus in question. As is well known, elastic electron scattering can allow for very precise determinations of nuclear form factors and hence nuclear charge densities for spherical or near-spherical nuclei. We use charge densities derived from elastic electron scattering data to calculate model independent, analytic form factors for various target nuclei important in dark matter searches, such as Si, Ge, S, Ca and others. We have found that for nuclear recoils in the range of 1-100 keV significant differences in cross sections and rates exist when the model independent form factors are used: at 30 keV nuclear recoil the form factors squared differ by a factor of 1.06 for $^{28}$Si, 1.11 for $^{40}$Ca, 1.27 for $^{70}$Ge, and 1.92 for $^{129}$Xe. We show the effect of different form factors on the upper limit on the WIMP-proton cross section obtained with a hypothetical $^{70}$Ge detector during a 100 kg-day effective exposure. Helm form factors with various parameter choices differ at most by 10--20% from the best (Fourier Bessel) form factor, and can approach it to better than 1% if the parameters are chosen to mimic the actual nuclear density.
[ { "created": "Thu, 3 Aug 2006 18:34:23 GMT", "version": "v1" }, { "created": "Mon, 13 Aug 2007 19:48:07 GMT", "version": "v2" } ]
2010-10-27
[ [ "Duda", "Gintaras", "" ], [ "Kemper", "Ann", "" ], [ "Gondolo", "Paolo", "" ] ]
Theoretical calculations of neutralino-nucleon interaction rates with various nuclei are of great interest to direct dark matter searches such as CDMS, EDELWEISS, ZEPLIN, and other experiments since they are used to establish upper bounds on the WIMP-proton cross section. These interaction rates and cross sections are generally computed with standard, one or two parameter model-dependent nuclear form factors, which may not exactly mirror the actual form factor for the particular nucleus in question. As is well known, elastic electron scattering can allow for very precise determinations of nuclear form factors and hence nuclear charge densities for spherical or near-spherical nuclei. We use charge densities derived from elastic electron scattering data to calculate model independent, analytic form factors for various target nuclei important in dark matter searches, such as Si, Ge, S, Ca and others. We have found that for nuclear recoils in the range of 1-100 keV significant differences in cross sections and rates exist when the model independent form factors are used: at 30 keV nuclear recoil the form factors squared differ by a factor of 1.06 for $^{28}$Si, 1.11 for $^{40}$Ca, 1.27 for $^{70}$Ge, and 1.92 for $^{129}$Xe. We show the effect of different form factors on the upper limit on the WIMP-proton cross section obtained with a hypothetical $^{70}$Ge detector during a 100 kg-day effective exposure. Helm form factors with various parameter choices differ at most by 10--20% from the best (Fourier Bessel) form factor, and can approach it to better than 1% if the parameters are chosen to mimic the actual nuclear density.
hep-ph/9406262
Hai-Yang Cheng
Hai-Yang Cheng
Nonfactorizable Contributions to Nonleptonic Weak Decays of Heavy Mesons
14 pages, IP-ASTP-11-94
Phys.Lett. B335 (1994) 428-435
10.1016/0370-2693(94)90374-3
null
hep-ph
null
Nonfactorizable contributions to exclusive two-body nonleptonic weak decays of heavy mesons arising from color octet currents, characterized by the parameter $r_2$, are extracted from the data. It is found that $r_2$ is equal to $\sim -0.67\,$, $-(0.9\sim 1.1),~-(1.2\sim 1.3)$, $\sim 0.36$ respectively for $D\to \bar{K}\pi,~\bar{K}^*\pi,~\bar{K}^*\rho,~\bar{B}\to D\pi$ decays. As expected, soft-gluon effects become stronger when the decay particles are less energetic, allowing more time for significant final-state strong interactions. As a consequence, the parameter $a_2$ is not universal and is channel or class dependent, contrary to the anticipation of the factorization approach. The leading $1/N_c$ expansion works most successfully for $D\to\bar{K}\pi$ decays as the subleading $1/N_c$ factorizable contribution is almost compensated by the soft-gluon effect. We argue that, in contrast to what happens in $B^-\to D^{(*)} \pi(\rho)$ decays, the nonfactorizable term and the subleading $1/N_c$ factorizable term in $\bar{B}\to \psi\bar{K}^{(*)}$ decays are opposite in signs, in accordance with a recent QCD sum rule calculation. Implications are discussed.
[ { "created": "Thu, 9 Jun 1994 15:57:43 GMT", "version": "v1" } ]
2009-10-28
[ [ "Cheng", "Hai-Yang", "" ] ]
Nonfactorizable contributions to exclusive two-body nonleptonic weak decays of heavy mesons arising from color octet currents, characterized by the parameter $r_2$, are extracted from the data. It is found that $r_2$ is equal to $\sim -0.67\,$, $-(0.9\sim 1.1),~-(1.2\sim 1.3)$, $\sim 0.36$ respectively for $D\to \bar{K}\pi,~\bar{K}^*\pi,~\bar{K}^*\rho,~\bar{B}\to D\pi$ decays. As expected, soft-gluon effects become stronger when the decay particles are less energetic, allowing more time for significant final-state strong interactions. As a consequence, the parameter $a_2$ is not universal and is channel or class dependent, contrary to the anticipation of the factorization approach. The leading $1/N_c$ expansion works most successfully for $D\to\bar{K}\pi$ decays as the subleading $1/N_c$ factorizable contribution is almost compensated by the soft-gluon effect. We argue that, in contrast to what happens in $B^-\to D^{(*)} \pi(\rho)$ decays, the nonfactorizable term and the subleading $1/N_c$ factorizable term in $\bar{B}\to \psi\bar{K}^{(*)}$ decays are opposite in signs, in accordance with a recent QCD sum rule calculation. Implications are discussed.
2306.06091
Yu-Kuo Hsiao
Yu-Kuo Hsiao, Shu-Qi Yang, Wen-Juan Wei, Bai-Cian Ke
Testing the light scalar meson as a non-$q\bar q$ state in semileptonic $D$ decays
10 pages, 1 figure, 1 table
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
To distinguish between the normal $q\bar q$ and exotic diquark-antidiqark ($q^2\bar q^2$) contents of the lowest-lying scalar meson ($S_0$), we investigate the semileptonic $D\to S_0 e^+\nu_e, S_0\to M_1 M_2$ decays, where $M_{1(2)}$ represents a pseudoscalar meson. With the form factors extracted from the current data, we calculate ${\cal B}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^0\pi^0) =(12.9^{+6.3}_{-4.9})\times 10^{-4}$ and $(0.8^{+1.2}_{-0.7})\times 10^{-4}$ for the $q\bar q$ and $q^2\bar q^2$ quark structures, respectively, and compare them to the experimental upper limit: $6.4\times 10^{-4}$. It is clearly seen that $S_0$ prefers to be the $q^2\bar q^2$ bound state. Particularly, ${\cal B}_{q\bar q}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^+\pi^-) =(25.8^{+12.5}_{-\;\,9.8})\times 10^{-4}$ and ${\cal B}_{q^2\bar q^2}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^+\pi^-) =(1.5^{+2.4}_{-1.3})\times 10^{-4}$ are predicted to deviate far from each other, useful for a clear experimental investigation.
[ { "created": "Fri, 9 Jun 2023 17:52:08 GMT", "version": "v1" } ]
2023-06-12
[ [ "Hsiao", "Yu-Kuo", "" ], [ "Yang", "Shu-Qi", "" ], [ "Wei", "Wen-Juan", "" ], [ "Ke", "Bai-Cian", "" ] ]
To distinguish between the normal $q\bar q$ and exotic diquark-antidiqark ($q^2\bar q^2$) contents of the lowest-lying scalar meson ($S_0$), we investigate the semileptonic $D\to S_0 e^+\nu_e, S_0\to M_1 M_2$ decays, where $M_{1(2)}$ represents a pseudoscalar meson. With the form factors extracted from the current data, we calculate ${\cal B}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^0\pi^0) =(12.9^{+6.3}_{-4.9})\times 10^{-4}$ and $(0.8^{+1.2}_{-0.7})\times 10^{-4}$ for the $q\bar q$ and $q^2\bar q^2$ quark structures, respectively, and compare them to the experimental upper limit: $6.4\times 10^{-4}$. It is clearly seen that $S_0$ prefers to be the $q^2\bar q^2$ bound state. Particularly, ${\cal B}_{q\bar q}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^+\pi^-) =(25.8^{+12.5}_{-\;\,9.8})\times 10^{-4}$ and ${\cal B}_{q^2\bar q^2}(D_s^+\to \sigma_0 e^+\nu_e,\sigma_0\to\pi^+\pi^-) =(1.5^{+2.4}_{-1.3})\times 10^{-4}$ are predicted to deviate far from each other, useful for a clear experimental investigation.
1111.3716
Yi Ling
Yi Ling
A note on superluminal neutrinos and deformed special relativity
2 pages
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this short note we remark that the OPERA measurement could be reconciled with information from SN1987a in the context of deformed special relativity without the loss of energy through Cherenkov-like process reported by Cohen and Glashow.
[ { "created": "Wed, 16 Nov 2011 05:58:24 GMT", "version": "v1" } ]
2011-11-17
[ [ "Ling", "Yi", "" ] ]
In this short note we remark that the OPERA measurement could be reconciled with information from SN1987a in the context of deformed special relativity without the loss of energy through Cherenkov-like process reported by Cohen and Glashow.
2302.06879
Michal Praszalowicz
Michal Praszalowicz
Heavy baryons in the Chiral Quark-Soliton Model
6 pages, 1 figure. Presented at the Conference Excited QCD, Giardini-Naxos, Italy, October 24 -- 28, 2022
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We review applications of the Chiral Quark Soliton Model to heavy baryons and to doubly heavy tetraquarks.
[ { "created": "Tue, 14 Feb 2023 08:01:20 GMT", "version": "v1" } ]
2023-02-15
[ [ "Praszalowicz", "Michal", "" ] ]
We review applications of the Chiral Quark Soliton Model to heavy baryons and to doubly heavy tetraquarks.
hep-ph/0410235
Paul Hoyer
Paul Hoyer and Stephane Peigne
QCD Green functions in a gluon field
21 pages, 7 figures. Minor modifications in text. Version to be published in JHEP
JHEP0412:051,2004
10.1088/1126-6708/2004/12/051
HIP-2004-53/TH, LAPTH-1073/04
hep-ph
null
We formulate a dressed perturbative expansion of QCD, where the standard diagrams are evaluated in the presence of a constant external gluon field whose magnitude is gaussian distributed. The approach is Poincar{\'e} and gauge invariant, and modifies the usual results for hard processes only by power suppressed contributions. Long distance propagation of quarks and gluons turns out to be inhibited due to a branch point singularity instead of a pole at $p^2=0$ in the quark and gluon propagators. The dressing keeps the (massless) quarks in q qbar fluctuations of the photon at a finite distance from each other.
[ { "created": "Fri, 15 Oct 2004 16:55:40 GMT", "version": "v1" }, { "created": "Sat, 16 Oct 2004 07:31:06 GMT", "version": "v2" }, { "created": "Thu, 23 Dec 2004 12:07:19 GMT", "version": "v3" } ]
2008-11-26
[ [ "Hoyer", "Paul", "" ], [ "Peigne", "Stephane", "" ] ]
We formulate a dressed perturbative expansion of QCD, where the standard diagrams are evaluated in the presence of a constant external gluon field whose magnitude is gaussian distributed. The approach is Poincar{\'e} and gauge invariant, and modifies the usual results for hard processes only by power suppressed contributions. Long distance propagation of quarks and gluons turns out to be inhibited due to a branch point singularity instead of a pole at $p^2=0$ in the quark and gluon propagators. The dressing keeps the (massless) quarks in q qbar fluctuations of the photon at a finite distance from each other.
1204.0478
Natascia Vignaroli
Natascia Vignaroli
$\Delta F=1$ constraints on composite Higgs models with LR parity
35 pp. Version to appear in PRD
Phys. Rev. D 86, 115011 (2012)
10.1103/PhysRevD.86.115011
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the bounds on the spectrum of composite Higgs models (CHM) that come from flavor observables, by means of simple two-site effective Lagrangians, which incorporate a custodial symmetry and a Left-Right parity and which could also be adopted in further phenomenological studies on CHM. We derive, in particular, an important constraint on the masses of the $(t_L, b_L)$ partners, which does not depend on the flavor structure of the sector beyond the SM. This bound is obtained from the "infrared" contribution to $b \to s\gamma$ induced by the flavor-conserving effective vertex $Wt_Rb_R$. We find that the presence of a custodial symmetry can play a role in protecting this effective coupling and, as a consequence, in attenuating the constraint, which, however, remains of the order of 1 TeV. In addition to this bound, we calculate the constraints from the "ultraviolet" contribution to $b \to s \gamma$, induced by loops of heavy fermions, and to $\epsilon^{'}/\epsilon_K$.
[ { "created": "Mon, 2 Apr 2012 17:42:40 GMT", "version": "v1" }, { "created": "Tue, 17 Jul 2012 16:48:14 GMT", "version": "v2" }, { "created": "Wed, 7 Nov 2012 20:10:21 GMT", "version": "v3" } ]
2012-12-06
[ [ "Vignaroli", "Natascia", "" ] ]
We analyze the bounds on the spectrum of composite Higgs models (CHM) that come from flavor observables, by means of simple two-site effective Lagrangians, which incorporate a custodial symmetry and a Left-Right parity and which could also be adopted in further phenomenological studies on CHM. We derive, in particular, an important constraint on the masses of the $(t_L, b_L)$ partners, which does not depend on the flavor structure of the sector beyond the SM. This bound is obtained from the "infrared" contribution to $b \to s\gamma$ induced by the flavor-conserving effective vertex $Wt_Rb_R$. We find that the presence of a custodial symmetry can play a role in protecting this effective coupling and, as a consequence, in attenuating the constraint, which, however, remains of the order of 1 TeV. In addition to this bound, we calculate the constraints from the "ultraviolet" contribution to $b \to s \gamma$, induced by loops of heavy fermions, and to $\epsilon^{'}/\epsilon_K$.
hep-ph/0605198
Bjorn O. Lange
Bjorn O. Lange (MIT, LNS)
Inclusive semileptonic decays of the B meson
Invited talk at "Flavour Physics and CP Violation Conference," Vancouver, 2006, 6 pages. To be published Electronic Conference Proceedings Archive
null
null
MIT-CTP 3741
hep-ph
null
This talk is a short review on the theoretical issues and uncertainties in the calculation of partial decay rates in inclusive B decays. The main emphasis is on charmless semileptonic decays, the B -> X(s) gamma photon spectrum, and the extraction of Vub using model-independent methods.
[ { "created": "Wed, 17 May 2006 18:09:55 GMT", "version": "v1" } ]
2007-05-23
[ [ "Lange", "Bjorn O.", "", "MIT, LNS" ] ]
This talk is a short review on the theoretical issues and uncertainties in the calculation of partial decay rates in inclusive B decays. The main emphasis is on charmless semileptonic decays, the B -> X(s) gamma photon spectrum, and the extraction of Vub using model-independent methods.
2110.15927
Edward Shuryak
Edward Shuryak and Ismail Zahed
Hadronic structure on the light-front I.\ Instanton effects and quark-antiquark effective potentials
v2 has some text editing and notation clarifications
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
This is the first of a sequence of papers that address the non-perturbative origin of the central, and spin-dependent forces between quarks. Its main thrust is a focus on meson spectroscopy in the center of mass frame. We suggest a "dense instanton ensemble" model for the QCD vacuum, to explain the interquark forces in mesons, from quarkonia to heavy-light and light-light ones, to the extent it is possible. The sequels will show how to export these interactions to the light front, and derive the corresponding Hamiltonians and mesonic wavefunctions.
[ { "created": "Fri, 29 Oct 2021 17:21:38 GMT", "version": "v1" }, { "created": "Tue, 9 Aug 2022 17:07:25 GMT", "version": "v2" } ]
2022-08-10
[ [ "Shuryak", "Edward", "" ], [ "Zahed", "Ismail", "" ] ]
This is the first of a sequence of papers that address the non-perturbative origin of the central, and spin-dependent forces between quarks. Its main thrust is a focus on meson spectroscopy in the center of mass frame. We suggest a "dense instanton ensemble" model for the QCD vacuum, to explain the interquark forces in mesons, from quarkonia to heavy-light and light-light ones, to the extent it is possible. The sequels will show how to export these interactions to the light front, and derive the corresponding Hamiltonians and mesonic wavefunctions.
2311.08789
Wei Kou
Wei Kou, Xurong Chen
Unraveling Proton Strangeness: Determination of the Strangeness Sigma Term with Statistical Significance
8 pages, 3 figures, 4 tables, accepted by Physical Review D, some spelling mistakes are fixed
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
This study delves into the contribution of the strange quark within the proton, which influences several fundamental proton properties. By establishing a robust relationship between the proton's quantum anomalous energy and the sigma term, we successfully extract the contribution of the strangeness sigma term in the proton, obtaining it from parameterized fits of the differential cross-section using exponential and dipole forms. The extracted sigma term values are estimated to be $455.62\pm64.60$ MeV (exponential fit) and $337.74\pm106.79$ MeV (dipole fit). Additionally, we present novel results for the proton trace anomalous energy, observing values of $0.13\pm0.02$ (exponential fit) and $0.15 \pm 0.03$ (dipole fit). Our analysis integrates the novel data from the $J/\psi-007$ and GlueX collaborations, to some extent providing an experimental phenomenological window into the non-zero strange quark content inside proton, with the statistical significances: $7.1\sigma$ (exponential fit) and $3.2\sigma$ (dipole fit), respectively. Furthermore, we discussed the possibility of scheme-independence in the extraction results and examine the uniformity of sigma terms obtained from the datasets provided by the two collaborations. Our analysis may reveals compatibility between the extracted results of the respective experiments.
[ { "created": "Wed, 15 Nov 2023 09:02:47 GMT", "version": "v1" }, { "created": "Sat, 10 Feb 2024 03:32:37 GMT", "version": "v2" }, { "created": "Tue, 13 Feb 2024 03:09:34 GMT", "version": "v3" } ]
2024-02-14
[ [ "Kou", "Wei", "" ], [ "Chen", "Xurong", "" ] ]
This study delves into the contribution of the strange quark within the proton, which influences several fundamental proton properties. By establishing a robust relationship between the proton's quantum anomalous energy and the sigma term, we successfully extract the contribution of the strangeness sigma term in the proton, obtaining it from parameterized fits of the differential cross-section using exponential and dipole forms. The extracted sigma term values are estimated to be $455.62\pm64.60$ MeV (exponential fit) and $337.74\pm106.79$ MeV (dipole fit). Additionally, we present novel results for the proton trace anomalous energy, observing values of $0.13\pm0.02$ (exponential fit) and $0.15 \pm 0.03$ (dipole fit). Our analysis integrates the novel data from the $J/\psi-007$ and GlueX collaborations, to some extent providing an experimental phenomenological window into the non-zero strange quark content inside proton, with the statistical significances: $7.1\sigma$ (exponential fit) and $3.2\sigma$ (dipole fit), respectively. Furthermore, we discussed the possibility of scheme-independence in the extraction results and examine the uniformity of sigma terms obtained from the datasets provided by the two collaborations. Our analysis may reveals compatibility between the extracted results of the respective experiments.
2104.09513
Matthew Sievert
Andrey V. Sadofyev, Matthew D. Sievert, Ivan Vitev
Ab Initio Coupling of Jets to Collective Flow in the Opacity Expansion Approach
94 pages, 12 figures, 1 table
null
10.1103/PhysRevD.104.094044
LA-UR-21-21420
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the leading corrections to jet momentum broadening and medium-induced branching that arise from the velocity of the moving medium at first order in opacity. These results advance our knowledge of jet quenching and demonstrate how it couples to collective flow of the quark-gluon plasma in heavy-ion collisions and to the orbital motion of partons in cold nuclear matter in deep inelastic scattering at the electron-ion collider. We also compute the leading corrections to jet momentum broadening due to transverse gradients of temperature and density. We find that these effects lead to both anisotropic transverse momentum diffusion proportional to the medium velocity and anisotropic medium-induced radiation emitted preferentially in the direction of the flow. We isolate the relevant sub-eikonal corrections by working with jets composed of scalar particles with arbitrary color factors interacting with the medium by scalar QCD. Appropriate substitution of the color factors and light-front wave functions allow us to immediately apply the results to a range of processes including $q \rightarrow q g$ branching in real QCD. The resulting general expressions can be directly coupled to hydrodynamic simulations on an event-by-event basis to study the correlations between jet quenching and the dynamics of various forms of nuclear matter.
[ { "created": "Mon, 19 Apr 2021 18:00:01 GMT", "version": "v1" }, { "created": "Fri, 21 Jan 2022 02:58:30 GMT", "version": "v2" } ]
2022-01-24
[ [ "Sadofyev", "Andrey V.", "" ], [ "Sievert", "Matthew D.", "" ], [ "Vitev", "Ivan", "" ] ]
We calculate the leading corrections to jet momentum broadening and medium-induced branching that arise from the velocity of the moving medium at first order in opacity. These results advance our knowledge of jet quenching and demonstrate how it couples to collective flow of the quark-gluon plasma in heavy-ion collisions and to the orbital motion of partons in cold nuclear matter in deep inelastic scattering at the electron-ion collider. We also compute the leading corrections to jet momentum broadening due to transverse gradients of temperature and density. We find that these effects lead to both anisotropic transverse momentum diffusion proportional to the medium velocity and anisotropic medium-induced radiation emitted preferentially in the direction of the flow. We isolate the relevant sub-eikonal corrections by working with jets composed of scalar particles with arbitrary color factors interacting with the medium by scalar QCD. Appropriate substitution of the color factors and light-front wave functions allow us to immediately apply the results to a range of processes including $q \rightarrow q g$ branching in real QCD. The resulting general expressions can be directly coupled to hydrodynamic simulations on an event-by-event basis to study the correlations between jet quenching and the dynamics of various forms of nuclear matter.
1004.1469
FengLan Shao
Rui-qin Wang, Feng-lan Shao, Jun Song and Qu-bing Xie
Hadron yield correlation and constituent quark degree of freedom in heavy ion collisions
7 pages, 3 figures,
null
null
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
Based on the assumption of the production of deconfined quark matter, we use a quark combination model to systematically investigate hadron yields in heavy ion collisions from RHIC $\sqrt{s_{NN}}=200, 130, 62.4$ GeV to SPS $E_{beam}=158, 80, 40, 30, 20 $ AGeV. We find that as the collision energy is greater than or equal to 30 AGeV the yields of various hadrons, their correlations, in particular, the observables $A=\frac{\bar{\Lambda} k^{-} p}{\Lambda k^{+} \bar{p}}$ and $B=\frac{\Lambda k^{-}\bar{\Xi}^{+}}{\bar{\Lambda} k^{+}\Xi^{-}}$, are all reproduced; however, as the collision energy drops to 20 AGeV quark combination fails. This indicates that the constituent quark degrees of freedom represent a decisive factor in thermal hadron production above 30 AGeV and seem to be invalid at 20 AGeV. In addition, hadron yields as well as particle ratios at midrapidity in the most central Pb+Pb collisions at $\sqrt{s_{NN}}=5.5$ TeV are predicted.
[ { "created": "Fri, 9 Apr 2010 06:47:07 GMT", "version": "v1" } ]
2010-04-12
[ [ "Wang", "Rui-qin", "" ], [ "Shao", "Feng-lan", "" ], [ "Song", "Jun", "" ], [ "Xie", "Qu-bing", "" ] ]
Based on the assumption of the production of deconfined quark matter, we use a quark combination model to systematically investigate hadron yields in heavy ion collisions from RHIC $\sqrt{s_{NN}}=200, 130, 62.4$ GeV to SPS $E_{beam}=158, 80, 40, 30, 20 $ AGeV. We find that as the collision energy is greater than or equal to 30 AGeV the yields of various hadrons, their correlations, in particular, the observables $A=\frac{\bar{\Lambda} k^{-} p}{\Lambda k^{+} \bar{p}}$ and $B=\frac{\Lambda k^{-}\bar{\Xi}^{+}}{\bar{\Lambda} k^{+}\Xi^{-}}$, are all reproduced; however, as the collision energy drops to 20 AGeV quark combination fails. This indicates that the constituent quark degrees of freedom represent a decisive factor in thermal hadron production above 30 AGeV and seem to be invalid at 20 AGeV. In addition, hadron yields as well as particle ratios at midrapidity in the most central Pb+Pb collisions at $\sqrt{s_{NN}}=5.5$ TeV are predicted.
hep-ph/9710413
Robert Harlander
R. Harlander and M. Steinhauser
O(\alpha_s^2) Corrections to Top Quark Production at $e^+e^-$ Colliders
LaTeX, 13 pages, 10 figures included as ps-files. The complete paper, including figures, is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/
Eur.Phys.J.C2:151-158,1998
10.1007/s100520050129
MPI/PhT/97-66, TTP97-40
hep-ph
null
In this article we evaluate mass corrections up to $O((m^2/q^2)^6)$ to the three-loop polarization function induced by an axial-vector current. Special emphasis is put on the evaluation of the singlet diagram which is absent in the vector case. As a physical application $O(\alpha_s^2)$ corrections to the production of top quarks at future $e^+e^-$ colliders is considered. It is demonstrated that for center of mass energies $\sqrt{s} >~ 500$ GeV the inclusion of the first seven terms into the cross section leads to a reliable description.
[ { "created": "Mon, 20 Oct 1997 14:57:23 GMT", "version": "v1" } ]
2011-09-13
[ [ "Harlander", "R.", "" ], [ "Steinhauser", "M.", "" ] ]
In this article we evaluate mass corrections up to $O((m^2/q^2)^6)$ to the three-loop polarization function induced by an axial-vector current. Special emphasis is put on the evaluation of the singlet diagram which is absent in the vector case. As a physical application $O(\alpha_s^2)$ corrections to the production of top quarks at future $e^+e^-$ colliders is considered. It is demonstrated that for center of mass energies $\sqrt{s} >~ 500$ GeV the inclusion of the first seven terms into the cross section leads to a reliable description.
hep-ph/9405388
null
S. Catani and F. Hautmann
High-Energy Factorization and Small-X Deep Inelastic Scattering Beyond Leading Order
46 pages (+ 7 figures not included, available from the authors), Latex, Cavendish-HEP-94/01
Nucl.Phys. B427 (1994) 475-524
10.1016/0550-3213(94)90636-X
null
hep-ph
null
High-energy factorization in QCD is investigated beyond leading order and its relationship to the factorization theorem of mass singularities is established to any collinear accuracy. Flavour non-singlet observables are shown to be regular at small x order by order in perturbation theory. In the singlet sector, we derive the relevant master equations for the space-like evolution of gluons and quarks. Their solution enables us to sum next-to-leading corrections to the small-x behaviour of quark anomalous dimensions and deep inelastic scattering coefficient functions. We present results in both MSbar and DIS factorization schemes.
[ { "created": "Thu, 26 May 1994 13:16:31 GMT", "version": "v1" } ]
2009-10-28
[ [ "Catani", "S.", "" ], [ "Hautmann", "F.", "" ] ]
High-energy factorization in QCD is investigated beyond leading order and its relationship to the factorization theorem of mass singularities is established to any collinear accuracy. Flavour non-singlet observables are shown to be regular at small x order by order in perturbation theory. In the singlet sector, we derive the relevant master equations for the space-like evolution of gluons and quarks. Their solution enables us to sum next-to-leading corrections to the small-x behaviour of quark anomalous dimensions and deep inelastic scattering coefficient functions. We present results in both MSbar and DIS factorization schemes.
hep-ph/9609282
Alan R. White
Alan R. White
The Hard Gluon Component of the QCD Pomeron
8 pages, with 7 ps figures in the text
null
null
ANL-HEP-CP-96-74
hep-ph
null
We argue that deep-inelastic diffractive scaling provides fundamental insight into the QCD Pomeron. The logarithmic scaling violations seen experimentally are in conflict with the scale-invariance of the BFKL Pomeron and with phenomenological two-gluon models. Instead the Pomeron appears as a single gluon at short-distances, indicating the appearance of a Super-Critical phase of Reggeon Field Theory. That the color compensation takes place at a longer distance is consistent with the Pomeron carrying odd color charge parity.
[ { "created": "Fri, 6 Sep 1996 21:51:25 GMT", "version": "v1" } ]
2007-05-23
[ [ "White", "Alan R.", "" ] ]
We argue that deep-inelastic diffractive scaling provides fundamental insight into the QCD Pomeron. The logarithmic scaling violations seen experimentally are in conflict with the scale-invariance of the BFKL Pomeron and with phenomenological two-gluon models. Instead the Pomeron appears as a single gluon at short-distances, indicating the appearance of a Super-Critical phase of Reggeon Field Theory. That the color compensation takes place at a longer distance is consistent with the Pomeron carrying odd color charge parity.
1902.05480
Ulrich Haisch
Martin Gorbahn and Ulrich Haisch
Two-loop amplitudes for Higgs plus jet production involving a modified trilinear Higgs coupling
13 pages, 1 figure; v2: version accepted by JHEP
null
10.1007/JHEP04(2019)062
LTH 1198
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the contributions to the two-loop scattering amplitudes $h \to gg$, $h \to ggg$ and $h \to q \bar q g$ that arise from a modified trilinear Higgs coupling $\lambda$. Analytic expressions are obtained by performing an asymptotic expansion near the limit of infinitely heavy top quark. The calculated amplitudes are necessary to study the impact of the ${\cal O} (\lambda)$ corrections to the transverse momentum distributions ($p_{T,h}$) in single-Higgs production at hadron colliders for low and moderate values of $p_{T,h}$.
[ { "created": "Thu, 14 Feb 2019 16:28:14 GMT", "version": "v1" }, { "created": "Fri, 5 Apr 2019 14:09:44 GMT", "version": "v2" } ]
2019-05-01
[ [ "Gorbahn", "Martin", "" ], [ "Haisch", "Ulrich", "" ] ]
We calculate the contributions to the two-loop scattering amplitudes $h \to gg$, $h \to ggg$ and $h \to q \bar q g$ that arise from a modified trilinear Higgs coupling $\lambda$. Analytic expressions are obtained by performing an asymptotic expansion near the limit of infinitely heavy top quark. The calculated amplitudes are necessary to study the impact of the ${\cal O} (\lambda)$ corrections to the transverse momentum distributions ($p_{T,h}$) in single-Higgs production at hadron colliders for low and moderate values of $p_{T,h}$.
1007.5072
Carina Maria Zanetti
C. M. Zanetti and A. A. Natale
Nonleptonic $B$ meson decays in collinear pQCD at twist-3: Effects of dynamical masses of gluons and quarks
9 pages, 1 figure
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compute the amplitudes for non-leptonic annihilation decays of $B$ mesons into two particles within the pQCD collinear approach. The end point divergences are regulated with the help of an infrared finite gluon propagator characterized by a non-perturbative dynamical gluon mass consistent with recent lattice simulations. The divergences at twist-3 are regulated by a dynamical quark mass. Our results fit quite well the existent data of $B^0\to D_s^-K^+$ and $B^0\to D_s^{-*}\bar{K}^+$ for the expected range of dynamical gluon masses. We also make predictions for the rare decays $\bar{B}^0\to K^-K^+$, $\bar{B}^0_s\to \pi^-\pi^+,\pi^0\pi^0$, $B^+\to D_s^{(*)+}\bar{K}^0$, $B^0\to D_s^{\pm(*)} K^\mp$ and $B_s^0\to D^{\pm(*)} \pi^\mp, D^0\pi^0$.
[ { "created": "Wed, 28 Jul 2010 20:38:58 GMT", "version": "v1" } ]
2010-07-30
[ [ "Zanetti", "C. M.", "" ], [ "Natale", "A. A.", "" ] ]
We compute the amplitudes for non-leptonic annihilation decays of $B$ mesons into two particles within the pQCD collinear approach. The end point divergences are regulated with the help of an infrared finite gluon propagator characterized by a non-perturbative dynamical gluon mass consistent with recent lattice simulations. The divergences at twist-3 are regulated by a dynamical quark mass. Our results fit quite well the existent data of $B^0\to D_s^-K^+$ and $B^0\to D_s^{-*}\bar{K}^+$ for the expected range of dynamical gluon masses. We also make predictions for the rare decays $\bar{B}^0\to K^-K^+$, $\bar{B}^0_s\to \pi^-\pi^+,\pi^0\pi^0$, $B^+\to D_s^{(*)+}\bar{K}^0$, $B^0\to D_s^{\pm(*)} K^\mp$ and $B_s^0\to D^{\pm(*)} \pi^\mp, D^0\pi^0$.
1808.07615
Stephen P. Martin
Stephen P. Martin and Hiren H. Patel
Two-loop effective potential for generalized gauge fixing
53 pages
Phys. Rev. D 98, 076008 (2018)
10.1103/PhysRevD.98.076008
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We obtain the two-loop effective potential for general renormalizable theories, using a generalized gauge-fixing scheme that includes as special cases the background-field $R_\xi$ gauges, the Fermi gauges, and the familiar Landau gauge, and using dimensional regularization in the bare and \MSbar renormalization schemes. As examples, the results are then specialized to the Abelian Higgs model and to the Standard Model. In the case of the Standard Model, we study how the vacuum expectation value and the minimum vacuum energy depend numerically on the gauge-fixing parameters. The results at fixed two-loop order exhibit non-convergent behavior for sufficiently large gauge-fixing parameters; this can presumably be addressed by a resummation of higher-order contributions.
[ { "created": "Thu, 23 Aug 2018 03:15:08 GMT", "version": "v1" } ]
2018-10-24
[ [ "Martin", "Stephen P.", "" ], [ "Patel", "Hiren H.", "" ] ]
We obtain the two-loop effective potential for general renormalizable theories, using a generalized gauge-fixing scheme that includes as special cases the background-field $R_\xi$ gauges, the Fermi gauges, and the familiar Landau gauge, and using dimensional regularization in the bare and \MSbar renormalization schemes. As examples, the results are then specialized to the Abelian Higgs model and to the Standard Model. In the case of the Standard Model, we study how the vacuum expectation value and the minimum vacuum energy depend numerically on the gauge-fixing parameters. The results at fixed two-loop order exhibit non-convergent behavior for sufficiently large gauge-fixing parameters; this can presumably be addressed by a resummation of higher-order contributions.
2006.01545
Mirzayusuf Musakhanov
M. Musakhanov (1), N. Rakhimov (1), U.T. Yakhshiev (1,2,3) ((1) National University of Uzbekistan, (2) Inha University, (3) Institute of Nuclear Physics, AS RUz)
Heavy quark correlators in Instanton Liquid Model with perturbative corrections
13 pages, 7 figures, minor corrections
Phys. Rev. D 102, 076022 (2020)
10.1103/PhysRevD.102.076022
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the present work we consider the influence on the heavy quark correlators due to the instanton background in the framework of instanton liquid model (ILM) of QCD vacuum by taking into account also the perturbative gluon effects. For a single heavy quark this leads to the mass shift due to the direct-instanton nonperturbative and ILM modified perturbative contributions, respectively. In the heavy quark-antiquark ($Q\bar{Q}$) sector we obtain the potential consisting the direct instanton induced part and the one-gluon exchange (OGE) perturbative part which is screened at large distances due to the nonperturbative dynamics. At the region of interest corresponding to the heavy quark physics the screening effect in OGE can be well approximated by a Yukawa-type potential in terms of the dynamically generated gluon mass. A possible implication of the present studies to the phenomenology of heavy quarkonium is also discussed.
[ { "created": "Tue, 2 Jun 2020 12:10:25 GMT", "version": "v1" }, { "created": "Wed, 18 Nov 2020 09:21:57 GMT", "version": "v2" } ]
2020-11-19
[ [ "Musakhanov", "M.", "" ], [ "Rakhimov", "N.", "" ], [ "Yakhshiev", "U. T.", "" ] ]
In the present work we consider the influence on the heavy quark correlators due to the instanton background in the framework of instanton liquid model (ILM) of QCD vacuum by taking into account also the perturbative gluon effects. For a single heavy quark this leads to the mass shift due to the direct-instanton nonperturbative and ILM modified perturbative contributions, respectively. In the heavy quark-antiquark ($Q\bar{Q}$) sector we obtain the potential consisting the direct instanton induced part and the one-gluon exchange (OGE) perturbative part which is screened at large distances due to the nonperturbative dynamics. At the region of interest corresponding to the heavy quark physics the screening effect in OGE can be well approximated by a Yukawa-type potential in terms of the dynamically generated gluon mass. A possible implication of the present studies to the phenomenology of heavy quarkonium is also discussed.
0912.0613
Vladimir Petrov
V. A. Petrov
Explicit Chiral Symmetry Breaking as a Premise of the Cross-Sections' Rise
null
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We argue that if QCD yields a theory of interacting hadrons then explicit chiral symmetry breaking is a necessary condition for infinitely rising cross-sections. Otherwise cross-sections go to zero at high energies.
[ { "created": "Thu, 3 Dec 2009 10:04:24 GMT", "version": "v1" } ]
2009-12-04
[ [ "Petrov", "V. A.", "" ] ]
We argue that if QCD yields a theory of interacting hadrons then explicit chiral symmetry breaking is a necessary condition for infinitely rising cross-sections. Otherwise cross-sections go to zero at high energies.
hep-ph/0603123
Michele Frigerio
Michele Frigerio (Saclay, SPhT), Thomas Hambye (UAM) and Ernest Ma (UCR)
Right-Handed Sector Leptogenesis
14 pages, latex, axodraw; minor clarifications and references added, extended discussion of the signatures at colliders
JCAP 0609 (2006) 009
10.1088/1475-7516/2006/09/009
SACLAY-T06/024, UCRHEP-T408
hep-ph
null
Instead of creating the observed baryon asymmetry of the universe by the decay of right-handed (RH) neutrinos to left-handed leptons, we propose to generate it dominantly by the decay of the RH neutrinos to RH leptons. This mechanism turns out to be successful in large regions of parameter space. It may work, in particular, at a scale as low as $\sim$~TeV, with no need to invoke quasi-degenerate RH neutrino masses to resonantly enhance the asymmetry. Such a possibility can be probed experimentally by the observation at colliders of a singlet charged Higgs particle and of RH neutrinos. Other mechanisms which may lead to successful leptogenesis from the RH lepton sector interactions are also briefly presented. The incorporation of these scenarios in left-right symmetric and unified models is discussed.
[ { "created": "Thu, 16 Mar 2006 15:00:16 GMT", "version": "v1" }, { "created": "Tue, 17 Oct 2006 19:21:18 GMT", "version": "v2" } ]
2009-11-11
[ [ "Frigerio", "Michele", "", "Saclay, SPhT" ], [ "Hambye", "Thomas", "", "UAM" ], [ "Ma", "Ernest", "", "UCR" ] ]
Instead of creating the observed baryon asymmetry of the universe by the decay of right-handed (RH) neutrinos to left-handed leptons, we propose to generate it dominantly by the decay of the RH neutrinos to RH leptons. This mechanism turns out to be successful in large regions of parameter space. It may work, in particular, at a scale as low as $\sim$~TeV, with no need to invoke quasi-degenerate RH neutrino masses to resonantly enhance the asymmetry. Such a possibility can be probed experimentally by the observation at colliders of a singlet charged Higgs particle and of RH neutrinos. Other mechanisms which may lead to successful leptogenesis from the RH lepton sector interactions are also briefly presented. The incorporation of these scenarios in left-right symmetric and unified models is discussed.
0705.4383
Yury Bystritskiy
E. A. Kuraev, V. N. Pervushin, M. K. Volkov
To a question on the \eta \to \pi^0 \gamma \gamma decay width in meson-baryon chiral model
4 pages, 1 pic
JETPLett.86:164-166,2007
10.1134/S0021364007150039
null
hep-ph
null
It is shown in the work of one of the authors in 1979 (MKV) that the contribution to the amplitude of this decay from diagrams with one baryon loop is equal to zero and contributions from diagrams with meson loops appear very small. However, pole diagrams with intermediate vector mesons were not considered there. Here it is shown that contributions of these pole diagrams dominate. The meson-baryon chiral model used here is compared with known quark chiral models. The obtained results are in satisfactory agreement with recent experimental data.
[ { "created": "Wed, 30 May 2007 12:53:17 GMT", "version": "v1" }, { "created": "Sun, 24 Jun 2007 10:43:49 GMT", "version": "v2" } ]
2008-11-26
[ [ "Kuraev", "E. A.", "" ], [ "Pervushin", "V. N.", "" ], [ "Volkov", "M. K.", "" ] ]
It is shown in the work of one of the authors in 1979 (MKV) that the contribution to the amplitude of this decay from diagrams with one baryon loop is equal to zero and contributions from diagrams with meson loops appear very small. However, pole diagrams with intermediate vector mesons were not considered there. Here it is shown that contributions of these pole diagrams dominate. The meson-baryon chiral model used here is compared with known quark chiral models. The obtained results are in satisfactory agreement with recent experimental data.
1210.5501
Itay Yavin
Josef Pradler, Balraj Singh, and Itay Yavin
On an unverified nuclear decay and its role in the DAMA experiment
8 pages, 3 figures; v2 - published version; results unchanged; an addendum can be found in http://arxiv.org/abs/arXiv:1210.7548
Physics Letters B 720 (2013), pp. 399-404
10.1016/j.physletb.2013.02.033
null
hep-ph astro-ph.HE nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The rate of the direct decay of 40K to the ground state of 40Ar through electron capture has not been experimentally reported. Aside from its inherent importance for the theory of electron capture as the only such decay known of its type (unique third-forbidden), this decay presents an irreducible background in the DAMA experiment. We find that the presence of this background, as well as others, poses a challenge to any interpretation of the DAMA results in terms of a Dark Matter model with a small modulation fraction. A 10ppb contamination of natural potassium requires a 20% modulation fraction or more. A 20ppb contamination, which is reported as an upper limit by DAMA, disfavors any Dark Matter origin of the signal. This conclusion is based on the efficiency of detecting 40K decays as inferred from simulation. We propose measures to help clarify the situation.
[ { "created": "Fri, 19 Oct 2012 19:08:38 GMT", "version": "v1" }, { "created": "Tue, 26 Mar 2013 14:50:34 GMT", "version": "v2" } ]
2013-03-27
[ [ "Pradler", "Josef", "" ], [ "Singh", "Balraj", "" ], [ "Yavin", "Itay", "" ] ]
The rate of the direct decay of 40K to the ground state of 40Ar through electron capture has not been experimentally reported. Aside from its inherent importance for the theory of electron capture as the only such decay known of its type (unique third-forbidden), this decay presents an irreducible background in the DAMA experiment. We find that the presence of this background, as well as others, poses a challenge to any interpretation of the DAMA results in terms of a Dark Matter model with a small modulation fraction. A 10ppb contamination of natural potassium requires a 20% modulation fraction or more. A 20ppb contamination, which is reported as an upper limit by DAMA, disfavors any Dark Matter origin of the signal. This conclusion is based on the efficiency of detecting 40K decays as inferred from simulation. We propose measures to help clarify the situation.
0910.1584
Konstantin Matchev
Konstantin T. Matchev and Myeonghun Park
A general method for determining the masses of semi-invisibly decaying particles at hadron colliders
thoroughly revised; all new figures; new results on pages 3 and 4; new illustrative example; includes detector simulation. 4 pages, 6 figures, uses revtex and axodraw
Phys.Rev.Lett.107:061801,2011
10.1103/PhysRevLett.107.061801
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a general solution to the long standing problem of determining the masses of pair-produced, semi-invisibly decaying particles at hadron colliders. We define two new transverse kinematic variables, $M_{CT_\perp}$ and $M_{CT_\parallel}$, which are suitable one-dimensional projections of the contransverse mass $M_{CT}$. We derive analytical formulas for the boundaries of the kinematically allowed regions in the $(M_{CT_\perp},M_{CT_\parallel})$ and $(M_{CT_\perp},M_{CT})$ parameter planes, and introduce suitable variables $D_{CT_\parallel}$ and $D_{CT}$ to measure the distance to those boundaries on an event per event basis. We show that the masses can be reliably extracted from the endpoint measurements of $M_{CT_\perp}^{max}$ and $D_{CT}^{min}$ (or $D_{CT_\parallel}^{min}$). We illustrate our method with dilepton $t\bar{t}$ events at the LHC.
[ { "created": "Fri, 9 Oct 2009 19:29:29 GMT", "version": "v1" }, { "created": "Fri, 31 Dec 2010 16:36:20 GMT", "version": "v2" } ]
2011-08-22
[ [ "Matchev", "Konstantin T.", "" ], [ "Park", "Myeonghun", "" ] ]
We present a general solution to the long standing problem of determining the masses of pair-produced, semi-invisibly decaying particles at hadron colliders. We define two new transverse kinematic variables, $M_{CT_\perp}$ and $M_{CT_\parallel}$, which are suitable one-dimensional projections of the contransverse mass $M_{CT}$. We derive analytical formulas for the boundaries of the kinematically allowed regions in the $(M_{CT_\perp},M_{CT_\parallel})$ and $(M_{CT_\perp},M_{CT})$ parameter planes, and introduce suitable variables $D_{CT_\parallel}$ and $D_{CT}$ to measure the distance to those boundaries on an event per event basis. We show that the masses can be reliably extracted from the endpoint measurements of $M_{CT_\perp}^{max}$ and $D_{CT}^{min}$ (or $D_{CT_\parallel}^{min}$). We illustrate our method with dilepton $t\bar{t}$ events at the LHC.
2102.06830
Ying Zhang
Ying Zhang
The Minimal Flavor Structure from Decomposition of the Fermion Mass Matrix
15 pages, 5 figures, 2 tables, includes appendix
Nuclear Physics B 976 (2022) 115699
10.1016/j.nuclphysb.2022.115699
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The minimal flavor structures for both quarks and leptons are proposed to address fermion mass hierarchy and flavor mixings by bi-unitary decomposition of the fermion mass matrix. The real matrix ${\bf M}_0^f$ is completely responsive to family mass hierarchy, which is expressed by a close-to-flat matrix structure. The left-handed unitary phase ${\bf F}_L^f$ provides the origin of CP violation in quark and lepton mixings, which can be explained as a quantum effect between Yukawa interaction states and weak gauge states. The minimal flavor structure is realized by just 10 parameters without any redundancy, corresponding to 6 fermion masses, 3 mixing angles and 1 CP violation in the quark/lepton sector. This approach provides a general flavor structure independent of the specific quark or lepton flavor data. We verify the validation of the flavor structure by reproducing quark/lepton masses and mixings. Some possible scenarios that yield the flavor structure are also discussed.
[ { "created": "Sat, 13 Feb 2021 00:35:44 GMT", "version": "v1" }, { "created": "Thu, 29 Apr 2021 06:31:59 GMT", "version": "v2" }, { "created": "Wed, 23 Jun 2021 04:27:52 GMT", "version": "v3" }, { "created": "Tue, 15 Feb 2022 01:19:30 GMT", "version": "v4" } ]
2022-02-16
[ [ "Zhang", "Ying", "" ] ]
The minimal flavor structures for both quarks and leptons are proposed to address fermion mass hierarchy and flavor mixings by bi-unitary decomposition of the fermion mass matrix. The real matrix ${\bf M}_0^f$ is completely responsive to family mass hierarchy, which is expressed by a close-to-flat matrix structure. The left-handed unitary phase ${\bf F}_L^f$ provides the origin of CP violation in quark and lepton mixings, which can be explained as a quantum effect between Yukawa interaction states and weak gauge states. The minimal flavor structure is realized by just 10 parameters without any redundancy, corresponding to 6 fermion masses, 3 mixing angles and 1 CP violation in the quark/lepton sector. This approach provides a general flavor structure independent of the specific quark or lepton flavor data. We verify the validation of the flavor structure by reproducing quark/lepton masses and mixings. Some possible scenarios that yield the flavor structure are also discussed.
1109.2718
Nikolaos Stefanis
N. G. Stefanis
Pion-photon transition form factor. Living on the QCD frontier
6 pages, 3 figures; needs style files svglov2.clo, svjour2.cls (supplied). Presented at LIGHTCONE 2011, 23 - 27 May, 2011, Dallas, USA. Accepted for publication in Few-Body Systems. In v2 name of second author in [28] corrected. V3 is final version, published online 23. Sep 2011
Few-Body Systems Volume 52, Issue 3-4 (2012) 415-420
10.1007/s00601-011-0257-2
RUB-TPII-06/2011
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An analysis of all available data (CELLO, CLEO, \babar) in the range $[1\div 40]$ GeV$^2$ for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four contributions and next-to-next-to-leading order and twist-six corrections---the latter two via uncertainties. The antithetic trend between the \babar data for the $\gamma^*\gamma\pi^0$ and those for the $\gamma^*\gamma\eta(\eta')$ transition is pointed out, emphasizing the underlying antagonistic mechanisms: endpoint enhancement for the first and endpoint-suppression for the second---each associated with pseudoscalar meson distribution amplitudes with distinct endpoint characteristics.
[ { "created": "Tue, 13 Sep 2011 09:33:06 GMT", "version": "v1" }, { "created": "Thu, 15 Sep 2011 13:21:11 GMT", "version": "v2" }, { "created": "Wed, 28 Sep 2011 10:35:17 GMT", "version": "v3" } ]
2012-04-24
[ [ "Stefanis", "N. G.", "" ] ]
An analysis of all available data (CELLO, CLEO, \babar) in the range $[1\div 40]$ GeV$^2$ for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four contributions and next-to-next-to-leading order and twist-six corrections---the latter two via uncertainties. The antithetic trend between the \babar data for the $\gamma^*\gamma\pi^0$ and those for the $\gamma^*\gamma\eta(\eta')$ transition is pointed out, emphasizing the underlying antagonistic mechanisms: endpoint enhancement for the first and endpoint-suppression for the second---each associated with pseudoscalar meson distribution amplitudes with distinct endpoint characteristics.
2108.04874
Gl\`oria Monta\~na Faiget
Gloria Montana, Angels Ramos, Laura Tolos, and Juan M. Torres-Rincon
Temperature dependence of the properties of open heavy-flavor mesons
4 pages, 4 figures, contribution to the proceedings for the 19th International Conference on Strangeness in Quark Matter (SQM 2021), online 17-22 May 2021 (Submission to EPJ)
null
10.1051/epjconf/202225912008
null
hep-ph nucl-th
http://creativecommons.org/publicdomain/zero/1.0/
We address the modification of open heavy-flavor mesons in a hot medium of light mesons within an effective theory approach consistent with chiral and heavy-quark spin-flavor symmetries and the use of the imaginary time formalism to introduce the non-zero temperature effects to the theory. The unitarized scattering amplitudes, the ground-state self-energies and the corresponding spectral functions are calculated self-consistently. We use the thermal ground-state spectral functions obtained with this methodology to further calculate 1) open-charm meson Euclidean correlators, and 2) off-shell transport coefficients in the hadronic phase.
[ { "created": "Tue, 10 Aug 2021 18:53:45 GMT", "version": "v1" } ]
2022-02-16
[ [ "Montana", "Gloria", "" ], [ "Ramos", "Angels", "" ], [ "Tolos", "Laura", "" ], [ "Torres-Rincon", "Juan M.", "" ] ]
We address the modification of open heavy-flavor mesons in a hot medium of light mesons within an effective theory approach consistent with chiral and heavy-quark spin-flavor symmetries and the use of the imaginary time formalism to introduce the non-zero temperature effects to the theory. The unitarized scattering amplitudes, the ground-state self-energies and the corresponding spectral functions are calculated self-consistently. We use the thermal ground-state spectral functions obtained with this methodology to further calculate 1) open-charm meson Euclidean correlators, and 2) off-shell transport coefficients in the hadronic phase.
hep-ph/9806219
Misha Stephanov
M. Stephanov, K. Rajagopal and E. Shuryak
Signatures of the Tricritical Point in QCD
5 pages (published version)
Phys.Rev.Lett. 81 (1998) 4816-4819
10.1103/PhysRevLett.81.4816
ITP-SB-98-39, MIT-CTP-2748, SUNY-NTG-98-17
hep-ph nucl-th
null
Several approaches to QCD with two massless quarks at finite temperature T and baryon chemical potential mu suggest the existence of a tricritical point on the boundary of the phase with spontaneously broken chiral symmetry. In QCD with massive quarks there is then a critical point at the end of a first order transition line. We discuss possible experimental signatures of this point, which provide information about its location and properties. We propose a combination of event-by-event observables, including suppressed fluctuations in T and mu and, simultaneously, enhanced fluctuations in the multiplicity of soft pions.
[ { "created": "Mon, 1 Jun 1998 22:15:40 GMT", "version": "v1" }, { "created": "Tue, 9 Mar 1999 22:15:39 GMT", "version": "v2" } ]
2009-10-31
[ [ "Stephanov", "M.", "" ], [ "Rajagopal", "K.", "" ], [ "Shuryak", "E.", "" ] ]
Several approaches to QCD with two massless quarks at finite temperature T and baryon chemical potential mu suggest the existence of a tricritical point on the boundary of the phase with spontaneously broken chiral symmetry. In QCD with massive quarks there is then a critical point at the end of a first order transition line. We discuss possible experimental signatures of this point, which provide information about its location and properties. We propose a combination of event-by-event observables, including suppressed fluctuations in T and mu and, simultaneously, enhanced fluctuations in the multiplicity of soft pions.
hep-ph/9312320
Dr. Ivica Picek
J.O. Eeg and I. Picek
New contribution to anomalous radiative $K^0$-decays
13 p.
Phys.Lett. B323 (1994) 193-200
10.1016/0370-2693(94)90291-7
Oslo TP 17-93 and Zagreb ZTF - 93/11
hep-ph
null
We present a new contribution to the $K_L\rightarrow \gamma \gamma$ amplitude, which is ${\cal{O}}(p^4)$ within the counting rules of chiral perturbation theory. This direct (non-pole) amplitude, obtained from short-distance $s \rightarrow d \gamma$ quark diagrams of order $e G_F \alpha_s/\pi$, and similar $s \rightarrow d \gamma \gamma$ diagrams, can account for about half of the experimental amplitude. Closely following the description of the $\pi ^0\rightarrow \gamma \gamma$ and $K_L\rightarrow \gamma \gamma$ processes in the variants of the same low-energy QCD, we find that both of these processes are anomalous in the same sense. Then, by the anomaly-matching principle, we arrive from the chiral-quark to the bosonic counterparts for both of these processes. In this way we add the $K_L\rightarrow \gamma \gamma$ decay to the existing list of anomalous radiative prosesses.
[ { "created": "Tue, 21 Dec 1993 11:30:39 GMT", "version": "v1" } ]
2009-10-22
[ [ "Eeg", "J. O.", "" ], [ "Picek", "I.", "" ] ]
We present a new contribution to the $K_L\rightarrow \gamma \gamma$ amplitude, which is ${\cal{O}}(p^4)$ within the counting rules of chiral perturbation theory. This direct (non-pole) amplitude, obtained from short-distance $s \rightarrow d \gamma$ quark diagrams of order $e G_F \alpha_s/\pi$, and similar $s \rightarrow d \gamma \gamma$ diagrams, can account for about half of the experimental amplitude. Closely following the description of the $\pi ^0\rightarrow \gamma \gamma$ and $K_L\rightarrow \gamma \gamma$ processes in the variants of the same low-energy QCD, we find that both of these processes are anomalous in the same sense. Then, by the anomaly-matching principle, we arrive from the chiral-quark to the bosonic counterparts for both of these processes. In this way we add the $K_L\rightarrow \gamma \gamma$ decay to the existing list of anomalous radiative prosesses.
1904.07175
Luc\'ia Duarte
Luc\'ia Duarte, Javier Peressutti, Ismael Romero, Oscar A. Sampayo
Majorana neutrinos with effective interactions in B decays
26 pages, 10 figures
Eur.Phys. J C (2019) 79: 593
10.1140/epjc/s10052-019-7104-x
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the possible contribution of Majorana neutrinos to $B$ meson decays in an effective interaction formalism, in the mass range $0.5$ GeV $<m_N<5 $ GeV. We study the decay of the $B^-$ meson via $B^- \to \mu^- \mu^- \pi^+$ at LHCb, which is a signal for leptonic number violation and the presence of Majorana neutrinos, and put bounds on different new physics contributions, characterized by their Dirac-Lorentz structure. We also study the bounds imposed by the radiative $B$ decay ($B^- \rightarrow \mu^- \nu \gamma$) results from Belle. The obtained bounds are more restrictive than previous values found for dimension 6 four-fermion contact vectorial and scalar Majorana neutrino interactions in the context of the Left-Right symmetric model for higher Majorana masses at the LHC, showing that the direct calculation of the effective $N$ interactions contribution to different processes can help to put more stringent bounds to different UV-complete models parameterized by an effective Lagrangian.
[ { "created": "Mon, 15 Apr 2019 16:44:59 GMT", "version": "v1" }, { "created": "Fri, 19 Jul 2019 18:01:10 GMT", "version": "v2" } ]
2019-07-23
[ [ "Duarte", "Lucía", "" ], [ "Peressutti", "Javier", "" ], [ "Romero", "Ismael", "" ], [ "Sampayo", "Oscar A.", "" ] ]
We investigate the possible contribution of Majorana neutrinos to $B$ meson decays in an effective interaction formalism, in the mass range $0.5$ GeV $<m_N<5 $ GeV. We study the decay of the $B^-$ meson via $B^- \to \mu^- \mu^- \pi^+$ at LHCb, which is a signal for leptonic number violation and the presence of Majorana neutrinos, and put bounds on different new physics contributions, characterized by their Dirac-Lorentz structure. We also study the bounds imposed by the radiative $B$ decay ($B^- \rightarrow \mu^- \nu \gamma$) results from Belle. The obtained bounds are more restrictive than previous values found for dimension 6 four-fermion contact vectorial and scalar Majorana neutrino interactions in the context of the Left-Right symmetric model for higher Majorana masses at the LHC, showing that the direct calculation of the effective $N$ interactions contribution to different processes can help to put more stringent bounds to different UV-complete models parameterized by an effective Lagrangian.
hep-ph/9805440
Ulf-G. Meissner
Ulf-G. Mei{\ss}ner
Pion-nucleon scattering and isospin violation
9 pp, LaTeX, uses psfig and sprocl.sty, 3 figs, invited talk, workshop on "Future Directions in Quark-Nuclear Physics", Adelaide, March 1998
null
null
FZJ-IKP(TH)-1998-11
hep-ph nucl-th
null
I discuss low-energy pion-nucleon scattering in the framework of chiral perturbation theory. I argue that using this theoretical method one is able to handle the in some cases tremendous experimental accuracy (for the low partial waves). I then show how strong and electromagnetic isospin violation can be treated simultaneously. Some first results for neutral pion scattering and the $\sigma$-term are given.
[ { "created": "Mon, 25 May 1998 07:09:05 GMT", "version": "v1" }, { "created": "Thu, 4 Jun 1998 13:49:46 GMT", "version": "v2" } ]
2007-05-23
[ [ "Meißner", "Ulf-G.", "" ] ]
I discuss low-energy pion-nucleon scattering in the framework of chiral perturbation theory. I argue that using this theoretical method one is able to handle the in some cases tremendous experimental accuracy (for the low partial waves). I then show how strong and electromagnetic isospin violation can be treated simultaneously. Some first results for neutral pion scattering and the $\sigma$-term are given.
hep-ph/0610279
Saleh Sultansoy
Saleh Sultansoy (Gazi University, Dept. of Physics, Ankara, Turkey and Academy of Science, Institute of Physics, Baku, Azerbaijan)
Flavor Democracy in Particle Physics
Invited presentation at the Sixth International Conference of the Balkan Physical Union (BPU-6), August 22-26, 2006, Istanbul, Turkey
AIPConf.Proc.899:49-52,2007
10.1063/1.2733040
null
hep-ph hep-ex
null
The flavor democracy hypothesis was introduced in seventies taking in mind three Standard Model (SM) families. Later, this idea was disfavored by the large value of the t-quark mass. In nineties the hypothesis was revisited assuming that extra SM families exist. According to flavor democracy the fourth SM family should exist and there are serious arguments disfavoring the fifth SM family. The fourth SM family quarks lead to essential enhancement of the Higgs boson production cross-section at hadron colliders and the Tevatron can discover the Higgs boson before the LHC, if it mass is between 140 and 200 GeV. Then, one can handle "massless" Dirac neutrinos without see-saw mechanism. Concerning BSM physics, flavor democracy leads to several consequences: tan(beta) approx.eq. 40 if there are three MSSM families; super-partner of the right-handed neutrino can be the LSP; relatively light E(6)-inspired isosinglet quark etc. Finally, flavor democracy may give opportunity to handle "massless" composite objects within preonic models.
[ { "created": "Sat, 21 Oct 2006 18:31:25 GMT", "version": "v1" } ]
2008-11-26
[ [ "Sultansoy", "Saleh", "", "Gazi University, Dept. of Physics, Ankara, Turkey and\n Academy of Science, Institute of Physics, Baku, Azerbaijan" ] ]
The flavor democracy hypothesis was introduced in seventies taking in mind three Standard Model (SM) families. Later, this idea was disfavored by the large value of the t-quark mass. In nineties the hypothesis was revisited assuming that extra SM families exist. According to flavor democracy the fourth SM family should exist and there are serious arguments disfavoring the fifth SM family. The fourth SM family quarks lead to essential enhancement of the Higgs boson production cross-section at hadron colliders and the Tevatron can discover the Higgs boson before the LHC, if it mass is between 140 and 200 GeV. Then, one can handle "massless" Dirac neutrinos without see-saw mechanism. Concerning BSM physics, flavor democracy leads to several consequences: tan(beta) approx.eq. 40 if there are three MSSM families; super-partner of the right-handed neutrino can be the LSP; relatively light E(6)-inspired isosinglet quark etc. Finally, flavor democracy may give opportunity to handle "massless" composite objects within preonic models.
2312.16972
Shao-Feng Ge
Shao-Feng Ge and Pedro Pasquini and Liang Tan
Neutrino Mass Measurement with Cosmic Gravitational Focusing
41 pages, 6 figures, published JCAP version
null
null
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We thoroughly explore the cosmic gravitational focusing of cosmic neutrino fluid (C$\nu$F) by dark matter (DM) halo using both general relativity for a point source of gravitational potential and Boltzmann equations for continuous overdensities. Derived in the general way for both relativistic and non-relativistic neutrinos, our results show that the effect has fourth power dependence on the neutrino mass and temperature. With nonlinear mass dependence which is different from the cosmic microwave background (CMB) and large scale structure (LSS) observations, the cosmic gravitational focusing can provide an independent cosmological way of measuring the neutrino mass and ordering. We take DESI as an example to illustrate that the projected sensitivity as well as its synergy with existing terrestrial neutrino oscillation experiments and other cosmological observations can significantly improve the neutrino mass measurement.
[ { "created": "Thu, 28 Dec 2023 11:35:12 GMT", "version": "v1" }, { "created": "Thu, 4 Jul 2024 12:43:05 GMT", "version": "v2" } ]
2024-07-08
[ [ "Ge", "Shao-Feng", "" ], [ "Pasquini", "Pedro", "" ], [ "Tan", "Liang", "" ] ]
We thoroughly explore the cosmic gravitational focusing of cosmic neutrino fluid (C$\nu$F) by dark matter (DM) halo using both general relativity for a point source of gravitational potential and Boltzmann equations for continuous overdensities. Derived in the general way for both relativistic and non-relativistic neutrinos, our results show that the effect has fourth power dependence on the neutrino mass and temperature. With nonlinear mass dependence which is different from the cosmic microwave background (CMB) and large scale structure (LSS) observations, the cosmic gravitational focusing can provide an independent cosmological way of measuring the neutrino mass and ordering. We take DESI as an example to illustrate that the projected sensitivity as well as its synergy with existing terrestrial neutrino oscillation experiments and other cosmological observations can significantly improve the neutrino mass measurement.
2012.03633
Hossein Mohseni Sadjadi
H. Mohseni Sadjadi, H. Yazdani Ahmadabadi
Damped Neutrino Oscillations in a Conformal Coupling Model
24 pages, 11 figures, minor corrections, published in Physical Review D
Phys. Rev. D 103, 065012 (2021)
10.1103/PhysRevD.103.065012
null
hep-ph gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Flavor transitions of Neutrinos with a nonstandard interaction are studied. A scalar field is conformally coupled to matter and neutrinos. This interaction alters the neutrino effective mass and its wavefunction leading to a damping factor, causing deficits in the probability densities and affecting the oscillation phase. As the matter density determines the scalar field's behavior, we also have an indirect matter density effect on the flavor conversion. We explain our results in the context of screening models and study the deficit in the total flux of electron-neutrinos produced in the Sun through the decay process and confront our results with observational data.
[ { "created": "Mon, 7 Dec 2020 12:26:19 GMT", "version": "v1" }, { "created": "Tue, 2 Mar 2021 10:31:34 GMT", "version": "v2" }, { "created": "Sat, 22 May 2021 10:26:42 GMT", "version": "v3" } ]
2021-05-25
[ [ "Sadjadi", "H. Mohseni", "" ], [ "Ahmadabadi", "H. Yazdani", "" ] ]
Flavor transitions of Neutrinos with a nonstandard interaction are studied. A scalar field is conformally coupled to matter and neutrinos. This interaction alters the neutrino effective mass and its wavefunction leading to a damping factor, causing deficits in the probability densities and affecting the oscillation phase. As the matter density determines the scalar field's behavior, we also have an indirect matter density effect on the flavor conversion. We explain our results in the context of screening models and study the deficit in the total flux of electron-neutrinos produced in the Sun through the decay process and confront our results with observational data.
hep-ph/0703280
Vadim Bednyakov
V.A.Bednyakov (LNP JINR), N.D.Giokaris (University of Athens), A.V.Bednyakov (BLTP JINR)
On Higgs mass generation mechanism in the Standard Model
43 pages, 2 figures, talk given at JINR ATLAS physics workshop
Phys.Part.Nucl.39:13-36,2008
10.1007/s11496-008-1002-9
null
hep-ph
null
The mass-generation mechanism is the most urgent problem of the modern particle physics. The discovery and study of the Higgs boson with the Large Hadron Collider at CERN are the highest priority steps to solve the problem. In this paper, the Standard Model Higgs mechanism of the elementary particle mass generation is reviewed with pedagogical details. The discussion of the Higgs quadric self-coupling \lambda parameter and the bounds to the Higgs boson mass are presented. In particular, the unitarity, triviality, and stability constraints on the Higgs boson mass are discussed. The generation of the finite value for the \lambda parameter due to quantum corrections via effective potential is illustrated. Some simple predictions for the top quark and the Higgs boson masses are given when both the top Yukawa coupling and the Higgs self-coupling \lambda are equal to 1.
[ { "created": "Tue, 27 Mar 2007 10:48:20 GMT", "version": "v1" } ]
2008-11-26
[ [ "Bednyakov", "V. A.", "", "LNP JINR" ], [ "Giokaris", "N. D.", "", "University of Athens" ], [ "Bednyakov", "A. V.", "", "BLTP JINR" ] ]
The mass-generation mechanism is the most urgent problem of the modern particle physics. The discovery and study of the Higgs boson with the Large Hadron Collider at CERN are the highest priority steps to solve the problem. In this paper, the Standard Model Higgs mechanism of the elementary particle mass generation is reviewed with pedagogical details. The discussion of the Higgs quadric self-coupling \lambda parameter and the bounds to the Higgs boson mass are presented. In particular, the unitarity, triviality, and stability constraints on the Higgs boson mass are discussed. The generation of the finite value for the \lambda parameter due to quantum corrections via effective potential is illustrated. Some simple predictions for the top quark and the Higgs boson masses are given when both the top Yukawa coupling and the Higgs self-coupling \lambda are equal to 1.
1801.05821
Mikko Laine
S. Biondini and M. Laine
Thermal dark matter co-annihilating with a strongly interacting scalar
19 pages. v2: clarifications added, published version
JHEP 1804 (2018) 072
10.1007/JHEP04(2018)072
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently many investigations have considered Majorana dark matter co-annihilating with bound states formed by a strongly interacting scalar field. However only the gluon radiation contribution to bound state formation and dissociation, which at high temperatures is subleading to soft 2->2 scatterings, has been included. Making use of a non-relativistic effective theory framework and solving a plasma-modified Schrodinger equation, we address the effect of soft 2->2 scatterings as well as the thermal dissociation of bound states. We argue that the mass splitting between the Majorana and scalar field has in general both a lower and an upper bound, and that the dark matter mass scale can be pushed at least up to 5...6 TeV.
[ { "created": "Wed, 17 Jan 2018 19:01:25 GMT", "version": "v1" }, { "created": "Thu, 3 May 2018 11:48:24 GMT", "version": "v2" } ]
2018-05-04
[ [ "Biondini", "S.", "" ], [ "Laine", "M.", "" ] ]
Recently many investigations have considered Majorana dark matter co-annihilating with bound states formed by a strongly interacting scalar field. However only the gluon radiation contribution to bound state formation and dissociation, which at high temperatures is subleading to soft 2->2 scatterings, has been included. Making use of a non-relativistic effective theory framework and solving a plasma-modified Schrodinger equation, we address the effect of soft 2->2 scatterings as well as the thermal dissociation of bound states. We argue that the mass splitting between the Majorana and scalar field has in general both a lower and an upper bound, and that the dark matter mass scale can be pushed at least up to 5...6 TeV.
hep-ph/0406225
Graeme Watt
A.D. Martin, M.G. Ryskin, G. Watt
Simultaneous QCD analysis of diffractive and inclusive DIS data
11 pages, 3 figures. Version published as a Rapid Communication in Phys. Rev. D
Phys.Rev.D70:091502,2004
10.1103/PhysRevD.70.091502
IPPP-04-31, DCPT-04-62
hep-ph
null
We perform a NLO QCD analysis of deep-inelastic scattering data, in which we account for absorptive corrections. These corrections are determined from a simultaneous analysis of diffractive deep-inelastic data. The absorptive effects are found to enhance the size of the gluon distribution at small x, such that a negative input gluon distribution at Q^2 = 1 GeV^2 is no longer required. We discuss the problem that the gluon distribution is valence-like at low scales, whereas the sea quark distribution grows with decreasing x. Our study hints at the possible importance of power corrections for Q^2 \simeq 1--2 GeV^2.
[ { "created": "Mon, 21 Jun 2004 19:43:14 GMT", "version": "v1" }, { "created": "Tue, 9 Nov 2004 10:50:19 GMT", "version": "v2" } ]
2014-11-17
[ [ "Martin", "A. D.", "" ], [ "Ryskin", "M. G.", "" ], [ "Watt", "G.", "" ] ]
We perform a NLO QCD analysis of deep-inelastic scattering data, in which we account for absorptive corrections. These corrections are determined from a simultaneous analysis of diffractive deep-inelastic data. The absorptive effects are found to enhance the size of the gluon distribution at small x, such that a negative input gluon distribution at Q^2 = 1 GeV^2 is no longer required. We discuss the problem that the gluon distribution is valence-like at low scales, whereas the sea quark distribution grows with decreasing x. Our study hints at the possible importance of power corrections for Q^2 \simeq 1--2 GeV^2.
2310.00550
Peihong Gu
Pei-Hong Gu
Ultralight Dirac neutrinos from nearly degenerate Higgs doublets
5 pages. More clarifications on the related mirror symmetry are added. Typos are corrected
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two Higgs doublets respect a mirror symmetry with spontaneous violation so that their vacuum expectation values can realize a small difference. Under this symmetry, three newly introduced right-handed neutrinos rather than the standard model fermions perform an odd transformation. Accordingly the neutrino masses and the charged fermion masses respectively are proportional to the difference and sum of the vacuum expectation values of two Higgs doublets. From a phenomenological perspective, such nearly degenerate Higgs doublets with large cancellation are equivalent to a Dirac seesaw mechanism with high suppression.
[ { "created": "Sun, 1 Oct 2023 02:37:31 GMT", "version": "v1" }, { "created": "Thu, 2 Nov 2023 17:56:44 GMT", "version": "v2" } ]
2023-11-03
[ [ "Gu", "Pei-Hong", "" ] ]
Two Higgs doublets respect a mirror symmetry with spontaneous violation so that their vacuum expectation values can realize a small difference. Under this symmetry, three newly introduced right-handed neutrinos rather than the standard model fermions perform an odd transformation. Accordingly the neutrino masses and the charged fermion masses respectively are proportional to the difference and sum of the vacuum expectation values of two Higgs doublets. From a phenomenological perspective, such nearly degenerate Higgs doublets with large cancellation are equivalent to a Dirac seesaw mechanism with high suppression.
1402.6427
Matthias Lutz F.M.
M.F.M. Lutz, D. Samart and Y. Yan
Combined large-N_c and heavy-quark operator analysis for the chiral Lagrangian with charmed baryons
34 pages - one table - corrections applied
null
10.1103/PhysRevD.90.056006
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The chiral $SU(3)$ Lagrangian with charmed baryons of spin $J^P=1/2^+$ and $J^P=3/2^+$ is analyzed. We consider all counter terms that are relevant at next-to-next-to-next-to-leading order (N$^3$LO) in a chiral extrapolation of the charmed baryon masses. At N$^2$LO we find 16 low-energy parameters. There are 3 mass parameters for the anti-triplet and the two sextet baryons, 6 parameters describing the meson-baryon vertices and 7 symmetry breaking parameters. The heavy-quark spin symmetry predicts four sum rules for the meson-baryon vertices and degenerate masses for the two baryon sextet fields. Here a large-$N_c$ operator analysis at NLO suggests the relevance of one further spin-symmetry breaking parameter. Going from N$^2$LO to N$^3$LO adds 17 chiral symmetry breaking parameters and 24 symmetry preserving parameters. For the leading symmetry conserving two-body counter terms involving two baryon fields and two Goldstone boson fields we find 36 terms. While the heavy-quark spin symmetry leads to $36-16=20$ sum rules, an expansion in $1/N_c$ at next-to-leading order (NLO) generates $36-7= 29$ parameter relations. A combined expansion leaves 3 unknown parameters only. For the symmetry breaking counter terms we find 17 terms, for which there are $17-9=8$ sum rules from the heavy-quark spin symmetry and $17-5=12 $ sum rules from a $1/N_c$ expansion at NLO.
[ { "created": "Wed, 26 Feb 2014 06:07:41 GMT", "version": "v1" }, { "created": "Tue, 10 Jun 2014 04:32:27 GMT", "version": "v2" } ]
2015-06-18
[ [ "Lutz", "M. F. M.", "" ], [ "Samart", "D.", "" ], [ "Yan", "Y.", "" ] ]
The chiral $SU(3)$ Lagrangian with charmed baryons of spin $J^P=1/2^+$ and $J^P=3/2^+$ is analyzed. We consider all counter terms that are relevant at next-to-next-to-next-to-leading order (N$^3$LO) in a chiral extrapolation of the charmed baryon masses. At N$^2$LO we find 16 low-energy parameters. There are 3 mass parameters for the anti-triplet and the two sextet baryons, 6 parameters describing the meson-baryon vertices and 7 symmetry breaking parameters. The heavy-quark spin symmetry predicts four sum rules for the meson-baryon vertices and degenerate masses for the two baryon sextet fields. Here a large-$N_c$ operator analysis at NLO suggests the relevance of one further spin-symmetry breaking parameter. Going from N$^2$LO to N$^3$LO adds 17 chiral symmetry breaking parameters and 24 symmetry preserving parameters. For the leading symmetry conserving two-body counter terms involving two baryon fields and two Goldstone boson fields we find 36 terms. While the heavy-quark spin symmetry leads to $36-16=20$ sum rules, an expansion in $1/N_c$ at next-to-leading order (NLO) generates $36-7= 29$ parameter relations. A combined expansion leaves 3 unknown parameters only. For the symmetry breaking counter terms we find 17 terms, for which there are $17-9=8$ sum rules from the heavy-quark spin symmetry and $17-5=12 $ sum rules from a $1/N_c$ expansion at NLO.
1511.03537
Federico Colecchia
Federico Colecchia
Data-driven estimation of neutral pileup particle multiplicity in high-luminosity hadron collider environments
Accepted for publication in the Proceedings of the 21st International Conference on Computing in High Energy and Nuclear Physics (CHEP2015) - Okinawa, Japan
J. Phys.: Conf. Ser. 664 (2015) 072013
10.1088/1742-6596/664/7/072013
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The upcoming operation regimes of the Large Hadron Collider are going to place stronger requirements on the rejection of particles originating from pileup, i.e. from interactions between other protons. For this reason, particle weighting techniques have recently been proposed in order to subtract pileup at the level of individual particles. We describe a choice of weights that, unlike others that rely on particle proximity, exploits the particle-level kinematic signatures of the high-energy scattering and of the pileup interactions. We illustrate the use of the weights to estimate the number density of neutral pileup particles inside individual events, and we elaborate on the complementarity between ours and other methods. We conclude by suggesting the idea of combining different sets of weights with a view to exploiting different features of the underlying processes for improved pileup subtraction at higher luminosity.
[ { "created": "Wed, 11 Nov 2015 15:41:47 GMT", "version": "v1" } ]
2016-01-19
[ [ "Colecchia", "Federico", "" ] ]
The upcoming operation regimes of the Large Hadron Collider are going to place stronger requirements on the rejection of particles originating from pileup, i.e. from interactions between other protons. For this reason, particle weighting techniques have recently been proposed in order to subtract pileup at the level of individual particles. We describe a choice of weights that, unlike others that rely on particle proximity, exploits the particle-level kinematic signatures of the high-energy scattering and of the pileup interactions. We illustrate the use of the weights to estimate the number density of neutral pileup particles inside individual events, and we elaborate on the complementarity between ours and other methods. We conclude by suggesting the idea of combining different sets of weights with a view to exploiting different features of the underlying processes for improved pileup subtraction at higher luminosity.
1708.07274
Harleen Dahiya Dr.
Nisha Dhiman and Harleen Dahiya
Decay constants of pseudoscalar and vector $B$ and $D$ mesons in the light-cone quark model
17 pages, 4 figures, 6 tables. Matches with the version to appear in EPJ Plus
Eur. Phys. J. Plus (2018) 133: 134
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied the decay constants of the pseudoscalar and the vector $B$ and $D$ mesons in the framework of the light-cone quark model. We have applied a variational method to the relativistic Hamiltonian with the Gaussian-type trial wave function to obtain the values of the scale parameter $\beta$ in different potential models. Furthermore, using the known values of the constituent quark masses of $u$, $d$, $s$, $c$ and $b$ quarks, we have obtained the numerical results for the decay constants. We have also compared our results with the other theoretical calculations and the existing experimental results. The present work predictions have many phenomenological applications in the domain of $CP$ violation and also in the determination of the CKM matrix elements.
[ { "created": "Thu, 24 Aug 2017 04:15:33 GMT", "version": "v1" }, { "created": "Mon, 5 Mar 2018 06:29:59 GMT", "version": "v2" } ]
2018-04-04
[ [ "Dhiman", "Nisha", "" ], [ "Dahiya", "Harleen", "" ] ]
We have studied the decay constants of the pseudoscalar and the vector $B$ and $D$ mesons in the framework of the light-cone quark model. We have applied a variational method to the relativistic Hamiltonian with the Gaussian-type trial wave function to obtain the values of the scale parameter $\beta$ in different potential models. Furthermore, using the known values of the constituent quark masses of $u$, $d$, $s$, $c$ and $b$ quarks, we have obtained the numerical results for the decay constants. We have also compared our results with the other theoretical calculations and the existing experimental results. The present work predictions have many phenomenological applications in the domain of $CP$ violation and also in the determination of the CKM matrix elements.
hep-ph/0407141
Alex Gomes Dias
Alex G. Dias, R. Martinez, V. Pleitez
Concerning the Landau Pole in 3-3-1 Models
17 pages, 1 figure, extended version
Eur.Phys.J. C39 (2005) 101-107
10.1140/epjc/s2004-02083-0
null
hep-ph
null
Some 3-3-1 models predict the existence of a non-perturbative regime at the TeV scale. We study in these models, and their supersymmetric extensions, the energy at which the non-perturbative limit and a Landau-like pole arise. An order of magnitude for the mass of the extra neutral vector boson, $Z^\prime$, present in these models is also obtained.
[ { "created": "Mon, 12 Jul 2004 20:26:13 GMT", "version": "v1" }, { "created": "Wed, 8 Dec 2004 14:13:02 GMT", "version": "v2" } ]
2009-11-10
[ [ "Dias", "Alex G.", "" ], [ "Martinez", "R.", "" ], [ "Pleitez", "V.", "" ] ]
Some 3-3-1 models predict the existence of a non-perturbative regime at the TeV scale. We study in these models, and their supersymmetric extensions, the energy at which the non-perturbative limit and a Landau-like pole arise. An order of magnitude for the mass of the extra neutral vector boson, $Z^\prime$, present in these models is also obtained.
1210.1264
Ivan Vitev
Ivan Vitev
Electroweak boson-tagged jet event asymmetries at the Large Hadron Collider
4 pages, 4 eps figures, Quark Matter 2012 proceedings
null
10.1016/j.nuclphysa.2013.02.111
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of $Z^0/\gamma^*$-tagged jet events and the momentum imbalance of $\gamma$-tagged jet events in $\sqrt{s}=2.76$ TeV reactions at the LHC. Our results combine the ${\cal O}(G_F\alpha_s^2)$, ${\cal O}(G_F\alpha_s^2)$ perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense QCD matter. We find that strong asymmetry momentum and imbalance, respectively, are generated in central Pb+Pb reactions that have little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for their shape and magnitude.
[ { "created": "Wed, 3 Oct 2012 23:56:09 GMT", "version": "v1" } ]
2015-06-11
[ [ "Vitev", "Ivan", "" ] ]
Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of $Z^0/\gamma^*$-tagged jet events and the momentum imbalance of $\gamma$-tagged jet events in $\sqrt{s}=2.76$ TeV reactions at the LHC. Our results combine the ${\cal O}(G_F\alpha_s^2)$, ${\cal O}(G_F\alpha_s^2)$ perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense QCD matter. We find that strong asymmetry momentum and imbalance, respectively, are generated in central Pb+Pb reactions that have little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for their shape and magnitude.
1402.2012
Boris Kopeliovich
B. Z. Kopeliovich, J. Nemchik, I. K. Potashnikova, and Ivan Schmidt
Quenching of high-pT hadrons: a non-energy-loss scenario
13 pages, 11 figures. Invited talk presented by B.Z.K. at International Conference on New Frontiers in Physics, Crete, 28 August - 5 September, 2013
null
10.1051/epjconf/20147100070
null
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A parton produced with a high transverse momentum in a hard collision is regenerating its color field, intensively radiating gluons and losing energy. This process cannot last long, if it ends up with production of a leading hadron carrying the main fraction z_h of the initial parton momentum. So energy conservation imposes severe constraints on the length scale of production of a single hadron with high pT. As a result, the main reason for hadron quenching observed in heavy ion collisions, is not energy loss, but attenuation of the produced colorless dipole in the created dense medium. The latter mechanism, calculated with the path-integral method, explains well the observed suppression of light hadrons and the elliptic flow in a wide range of energies, from the lowest energy of RHIC up to LHC, and in a wide range of transverse momenta. The values of the transport coefficient extracted from data range within 1-2 GeV^2/fm, dependent on energy, and agree well with the theoretical expectations.
[ { "created": "Mon, 10 Feb 2014 01:19:02 GMT", "version": "v1" } ]
2015-06-18
[ [ "Kopeliovich", "B. Z.", "" ], [ "Nemchik", "J.", "" ], [ "Potashnikova", "I. K.", "" ], [ "Schmidt", "Ivan", "" ] ]
A parton produced with a high transverse momentum in a hard collision is regenerating its color field, intensively radiating gluons and losing energy. This process cannot last long, if it ends up with production of a leading hadron carrying the main fraction z_h of the initial parton momentum. So energy conservation imposes severe constraints on the length scale of production of a single hadron with high pT. As a result, the main reason for hadron quenching observed in heavy ion collisions, is not energy loss, but attenuation of the produced colorless dipole in the created dense medium. The latter mechanism, calculated with the path-integral method, explains well the observed suppression of light hadrons and the elliptic flow in a wide range of energies, from the lowest energy of RHIC up to LHC, and in a wide range of transverse momenta. The values of the transport coefficient extracted from data range within 1-2 GeV^2/fm, dependent on energy, and agree well with the theoretical expectations.
hep-ph/9612297
Thomas Weigl
L. Mankiewicz, A.Saalfeld, T. Weigl (TU Munich)
On the analytical approximation to the GLAP evolution at small x and moderate Q^2
LaTeX, 13 pages including 6 figures, figure 5 replaced, to appear in Phys. Lett. B
Phys.Lett.B393:175-180,1997
10.1016/S0370-2693(96)01615-2
TUM/T39-96-25
hep-ph
null
Comparing the numerically evaluated solution to the leading order GLAP equations with its analytical small-x approximation we have found that in the domain covered by a large fraction of the HERA data the analytic approximation has to be augmented by the formally non-leading term which has been usually neglected. The corrected formula fits the data much better and provides a natural explanation of some of the deviations from the $\sigma$ scaling observed in the HERA kinematical range.
[ { "created": "Mon, 9 Dec 1996 13:20:43 GMT", "version": "v1" }, { "created": "Tue, 10 Dec 1996 16:11:55 GMT", "version": "v2" } ]
2014-11-17
[ [ "Mankiewicz", "L.", "", "TU Munich" ], [ "Saalfeld", "A.", "", "TU Munich" ], [ "Weigl", "T.", "", "TU Munich" ] ]
Comparing the numerically evaluated solution to the leading order GLAP equations with its analytical small-x approximation we have found that in the domain covered by a large fraction of the HERA data the analytic approximation has to be augmented by the formally non-leading term which has been usually neglected. The corrected formula fits the data much better and provides a natural explanation of some of the deviations from the $\sigma$ scaling observed in the HERA kinematical range.
hep-ph/0609228
Martti Raidal
Thomas Hambye, Kristjan Kannike, Ernest Ma, and Martti Raidal
Emanations of Dark Matter: Muon Anomalous Magnetic Moment, Radiative Neutrino Mass, and Novel Leptogenesis at the TeV Scale
12 pages, 3 figures
Phys.Rev.D75:095003,2007
10.1103/PhysRevD.75.095003
UCRHEP-T419
hep-ph
null
The evidence for dark matter signals a new class of particles at the TeV scale, which may manifest themselves indirectly through loop effects. In a simple model we show that these loop effects may be responsible for the enhanced muon anomalous magnetic moment, for the neutrino mass, as well as for leptogenesis in a novel way. This scenario can be verified at LHC experiments.
[ { "created": "Fri, 22 Sep 2006 05:28:17 GMT", "version": "v1" } ]
2008-11-26
[ [ "Hambye", "Thomas", "" ], [ "Kannike", "Kristjan", "" ], [ "Ma", "Ernest", "" ], [ "Raidal", "Martti", "" ] ]
The evidence for dark matter signals a new class of particles at the TeV scale, which may manifest themselves indirectly through loop effects. In a simple model we show that these loop effects may be responsible for the enhanced muon anomalous magnetic moment, for the neutrino mass, as well as for leptogenesis in a novel way. This scenario can be verified at LHC experiments.
1202.2533
Jorge Casalderrey-Solana
Jorge Casalderrey-Solana and David Mateos
Off-diagonal Flavour Susceptibilities from AdS/CFT
4 pages
null
10.1007/JHEP08(2012)165
ICCUB-12-075
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study flavour susceptibilities in the ${\cal N}=4$ SU(N) super Yang-Mills plasma coupled to two quark flavours at strong coupling and large $N$ by means of its gravity dual. The off-diagonal susceptibility is 1/N-suppressed and we compute it as a one-loop effect on the gravity side. Contrary to naive extrapolation from perturbative results, it attains a finite value in the infinite-coupling limit. Moreover, its parametric form is independent of whether or not meson bound states exist in the plasma. We conclude that caution must be exercised when drawing conclusions about the QCD plasma from lattice calculations of quark susceptibilities.
[ { "created": "Sun, 12 Feb 2012 15:02:51 GMT", "version": "v1" } ]
2015-06-04
[ [ "Casalderrey-Solana", "Jorge", "" ], [ "Mateos", "David", "" ] ]
We study flavour susceptibilities in the ${\cal N}=4$ SU(N) super Yang-Mills plasma coupled to two quark flavours at strong coupling and large $N$ by means of its gravity dual. The off-diagonal susceptibility is 1/N-suppressed and we compute it as a one-loop effect on the gravity side. Contrary to naive extrapolation from perturbative results, it attains a finite value in the infinite-coupling limit. Moreover, its parametric form is independent of whether or not meson bound states exist in the plasma. We conclude that caution must be exercised when drawing conclusions about the QCD plasma from lattice calculations of quark susceptibilities.
2211.15726
Rome Samanta
Debasish Borah, Suruj Jyoti Das, Rome Samanta and Federico R. Urban
PBH-infused seesaw origin of matter and unique gravitational waves
16 pages (one column), 5 figures, footnote-3 extended. Matches the JHEP version
JHEP03(2023)127
10.1007/JHEP03(2023)127
null
hep-ph astro-ph.CO
http://creativecommons.org/publicdomain/zero/1.0/
The Standard Model, extended with three right-handed (RH) neutrinos, is the simplest model that can explain light neutrino masses, the baryon asymmetry of the Universe, and dark matter (DM). Models in which RH neutrinos are light are generally easier to test in experiments. In this work, we show that, even if the RH neutrinos are super-heavy ($M_{i=1,2,3}>10^9$ GeV) -- close to the Grand Unification scale -- the model can be tested thanks to its distinct features on the stochastic Gravitational Wave (GW) background. We consider an early Universe filled with ultralight primordial black holes (PBH) that produce a super-heavy RH neutrino DM via Hawking radiation. The other pair of RH neutrinos generates the baryon asymmetry via thermal leptogenesis, much before the PBHs evaporate. GW interferometers can test this novel spectrum of masses thanks to the GWs induced by the PBH density fluctuations. In a more refined version, wherein a $U(1)$ gauge symmetry breaking dynamically generates the seesaw scale, the PBHs also cause observable spectral distortions on the GWs from the $U(1)$-breaking cosmic strings. Thence, a low-frequency GW feature related to DM genesis and detectable with a pulsar-timing array must correspond to a mid- or high-frequency GW signature related to baryogenesis at interferometer scales.
[ { "created": "Mon, 28 Nov 2022 19:25:21 GMT", "version": "v1" }, { "created": "Fri, 17 Mar 2023 19:28:14 GMT", "version": "v2" } ]
2023-03-21
[ [ "Borah", "Debasish", "" ], [ "Das", "Suruj Jyoti", "" ], [ "Samanta", "Rome", "" ], [ "Urban", "Federico R.", "" ] ]
The Standard Model, extended with three right-handed (RH) neutrinos, is the simplest model that can explain light neutrino masses, the baryon asymmetry of the Universe, and dark matter (DM). Models in which RH neutrinos are light are generally easier to test in experiments. In this work, we show that, even if the RH neutrinos are super-heavy ($M_{i=1,2,3}>10^9$ GeV) -- close to the Grand Unification scale -- the model can be tested thanks to its distinct features on the stochastic Gravitational Wave (GW) background. We consider an early Universe filled with ultralight primordial black holes (PBH) that produce a super-heavy RH neutrino DM via Hawking radiation. The other pair of RH neutrinos generates the baryon asymmetry via thermal leptogenesis, much before the PBHs evaporate. GW interferometers can test this novel spectrum of masses thanks to the GWs induced by the PBH density fluctuations. In a more refined version, wherein a $U(1)$ gauge symmetry breaking dynamically generates the seesaw scale, the PBHs also cause observable spectral distortions on the GWs from the $U(1)$-breaking cosmic strings. Thence, a low-frequency GW feature related to DM genesis and detectable with a pulsar-timing array must correspond to a mid- or high-frequency GW signature related to baryogenesis at interferometer scales.
1806.10932
Barbara Pasquini
B. Pasquini (1, 2) and S. Rodini (1, 2) ((1) Pavia U., (2) INFN, Pavia)
The twist-three distribution $e^q(x,k_\perp)$ in a light-front model
15 pages; 5 figures; 2 tables
Phys. Lett. B788 (2019) 414-424
10.1016/j.physletb.2018.11.033
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the twist-three, unpolarized, chiral-odd, transverse momentum dependent parton distribution (TMD) $e^q(x,k_\perp)$ within a light-front model. We review a model-independent decomposition of this TMD, which follows from the QCD equations of motion and is given in terms of a leading-twist mass term, a pure interaction-dependent contribution, and singular terms. The leading-twist and pure twist-three terms are represented in terms of overlap of light-front wave functions (LFWFs), taking into account the Fock states with three valence quark ($3q$) and three-quark plus one gluon ($3q+g$). The $3q$ and $3q+g$ LFWFs with total orbital angular momentum zero are modeled using a parametrization derived from the conformal expansion of the proton distribution amplitudes, with parameters fitted to reproduce available phenomenological information on the unpolarized leading-twist quark and gluon collinear parton distributions. Numerical predictions for both the quark TMD $e^q(x,k_\perp)$ and the collinear parton distribution $e^q(x)$ are presented, discussing the role of the quark-gluon correlations in the proton.
[ { "created": "Thu, 28 Jun 2018 13:02:56 GMT", "version": "v1" }, { "created": "Thu, 9 Aug 2018 16:17:40 GMT", "version": "v2" } ]
2018-12-06
[ [ "Pasquini", "B.", "" ], [ "Rodini", "S.", "" ] ]
We discuss the twist-three, unpolarized, chiral-odd, transverse momentum dependent parton distribution (TMD) $e^q(x,k_\perp)$ within a light-front model. We review a model-independent decomposition of this TMD, which follows from the QCD equations of motion and is given in terms of a leading-twist mass term, a pure interaction-dependent contribution, and singular terms. The leading-twist and pure twist-three terms are represented in terms of overlap of light-front wave functions (LFWFs), taking into account the Fock states with three valence quark ($3q$) and three-quark plus one gluon ($3q+g$). The $3q$ and $3q+g$ LFWFs with total orbital angular momentum zero are modeled using a parametrization derived from the conformal expansion of the proton distribution amplitudes, with parameters fitted to reproduce available phenomenological information on the unpolarized leading-twist quark and gluon collinear parton distributions. Numerical predictions for both the quark TMD $e^q(x,k_\perp)$ and the collinear parton distribution $e^q(x)$ are presented, discussing the role of the quark-gluon correlations in the proton.
hep-ph/9910275
Konstantin Matchev
Regina Demina (Kansas State U.), Joseph D. Lykken, Konstantin T. Matchev (Fermilab) and Andrei Nomerotski (Florida U.)
Stop and Sbottom Searches in Run II of the Fermilab Tevatron
30 pages, LaTeX, 10 figures
Phys.Rev.D62:035011,2000
10.1103/PhysRevD.62.035011
FERMILAB-PUB-99/259-T
hep-ph hep-ex
null
We estimate the Tevatron Run II potential for top and bottom squark searches. We find an impressive reach in several of the possible discovery channels. We also study some new channels which may arise in non-conventional supersymmetry models. In each case we rely on a detailed Monte Carlo simulation of the collider events and the CDF detector performance in Run I.
[ { "created": "Fri, 8 Oct 1999 20:49:19 GMT", "version": "v1" } ]
2009-10-09
[ [ "Demina", "Regina", "", "Kansas State U." ], [ "Lykken", "Joseph D.", "", "Fermilab" ], [ "Matchev", "Konstantin T.", "", "Fermilab" ], [ "Nomerotski", "Andrei", "", "Florida U." ] ]
We estimate the Tevatron Run II potential for top and bottom squark searches. We find an impressive reach in several of the possible discovery channels. We also study some new channels which may arise in non-conventional supersymmetry models. In each case we rely on a detailed Monte Carlo simulation of the collider events and the CDF detector performance in Run I.
2210.01501
Xiaoyu Lai
Xiaoyu Lai, Chengjun Xia, Renxin Xu
Bulk Strong Matter: the Trinity
12 pages, 2 figures. Accepted by Advances in Physics: X
ADVANCES IN PHYSICS: X (2023) VOL. 8, NO. 1, 2137433
10.1080/23746149.2022.2137433
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Our world is wonderful because of the normal but negligibly small baryonic part (i.e., atoms) although unknown dark matter and dark energy dominate the Universe. A stable atomic nucleus could be simply termed as ``strong matter'' since its nature is dominated by the fundamental strong interaction. Is there any other form of strong matter? Although nuclei are composed of 2-flavoured (i.e., up and down flavours of valence quarks) nucleons, it is conjectured that bulk strong matter could be 3-flavoured (with additional strange quarks) if the baryon number exceeds the critical value, $A_{\rm c}$, in which case quarks could be either free (so-called strange quark matter) or localized (in strangeons, coined by combining ``strange nucleon''). Bulk strong matter could be manifested in the form of compact stars, cosmic rays, and even dark matter. This trinity will be explained in this brief review, that may impact dramatically on today's physics, particularly in the era of multi-messenger astronomy after the discovery of gravitational wave.
[ { "created": "Tue, 4 Oct 2022 10:12:41 GMT", "version": "v1" }, { "created": "Sun, 6 Nov 2022 12:20:17 GMT", "version": "v2" } ]
2022-11-08
[ [ "Lai", "Xiaoyu", "" ], [ "Xia", "Chengjun", "" ], [ "Xu", "Renxin", "" ] ]
Our world is wonderful because of the normal but negligibly small baryonic part (i.e., atoms) although unknown dark matter and dark energy dominate the Universe. A stable atomic nucleus could be simply termed as ``strong matter'' since its nature is dominated by the fundamental strong interaction. Is there any other form of strong matter? Although nuclei are composed of 2-flavoured (i.e., up and down flavours of valence quarks) nucleons, it is conjectured that bulk strong matter could be 3-flavoured (with additional strange quarks) if the baryon number exceeds the critical value, $A_{\rm c}$, in which case quarks could be either free (so-called strange quark matter) or localized (in strangeons, coined by combining ``strange nucleon''). Bulk strong matter could be manifested in the form of compact stars, cosmic rays, and even dark matter. This trinity will be explained in this brief review, that may impact dramatically on today's physics, particularly in the era of multi-messenger astronomy after the discovery of gravitational wave.
1105.2139
Thorsten Feldmann
Thorsten Feldmann (IPPP, Univ. Durham)
Lepton Flavour Violation Theory
8 pages, contribution to the proceedings of "The 13th International Conference on B-Physics at Hadron Machines" (April 2011), Amsterdam
null
null
Durham IPPP/11/22, DCPT/11/44
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I discuss theoretical and phenomenological aspects of flavour violation in charged lepton transitions. This includes minimal extensions of the Standard Model within effective-theory approaches, as well as an incomplete selection of concrete new physics models.
[ { "created": "Wed, 11 May 2011 09:31:44 GMT", "version": "v1" } ]
2011-05-12
[ [ "Feldmann", "Thorsten", "", "IPPP, Univ. Durham" ] ]
I discuss theoretical and phenomenological aspects of flavour violation in charged lepton transitions. This includes minimal extensions of the Standard Model within effective-theory approaches, as well as an incomplete selection of concrete new physics models.
hep-ph/9712443
Beatriz de Carlos
T. Barreiro, B. de Carlos and E.J. Copeland (Sussex)
On non-perturbative corrections to the Kahler potential
11 pages, LaTex, uses psfig.sty with 4 figures
Phys.Rev. D57 (1998) 7354-7360
10.1103/PhysRevD.57.7354
SUSX-TH-97-024, IEM-FT-169/97
hep-ph hep-th
null
We present the results of a detailed investigation into the consequences of adding specific string motivated non-perturbative corrections to the usual tree level Kahler potential in dilaton dominated scenarios. The success of the model is judged through our ability to obtain a realistic VEV for the dilaton < Re S > ~ 2, corresponding to the true minima of the scalar potential and being associated with a reasonable value for the SUSY breaking scale via the gravitino mass. The status of the so-called moduli problem is also reviewed in each of the ansatze studied. Those include previous proposals made in the context of both the chiral and the linear multiplet formalisms to describe gaugino condensation, and a new ansatz which shows explicitly the equivalence between the two.
[ { "created": "Thu, 18 Dec 1997 19:19:36 GMT", "version": "v1" } ]
2009-10-30
[ [ "Barreiro", "T.", "", "Sussex" ], [ "de Carlos", "B.", "", "Sussex" ], [ "Copeland", "E. J.", "", "Sussex" ] ]
We present the results of a detailed investigation into the consequences of adding specific string motivated non-perturbative corrections to the usual tree level Kahler potential in dilaton dominated scenarios. The success of the model is judged through our ability to obtain a realistic VEV for the dilaton < Re S > ~ 2, corresponding to the true minima of the scalar potential and being associated with a reasonable value for the SUSY breaking scale via the gravitino mass. The status of the so-called moduli problem is also reviewed in each of the ansatze studied. Those include previous proposals made in the context of both the chiral and the linear multiplet formalisms to describe gaugino condensation, and a new ansatz which shows explicitly the equivalence between the two.
1009.4939
Sheldon Stone
Sheldon Stone
S-waves and the extraction of beta_s
Invited talk presented at Flavor Physics and CP Violation 2010, May 2010, Torino, Italy; to appear in proceedings. 6 pages 4 figures
PoS FPCP2010:011,2010
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The CP Violating asymmetry in Bs mixing (beta_s) is one of the most promising measurements where physics beyond the Standard Model could be revealed. As such, analyses need to be subjected to great scrutiny. The mode Bs -> J/psi\phi has been used, and the mode Bs -> \phi \phi proposed for future measurements. These modes both have two vector particles in the final state and thus angular analyses must be used to disentangle the contributions from CP+ and CP- configurations. The angular distributions, however, could be distorted by the presence of S-waves masquerading as low mass K+K- pairs, that could result in erroneous values of beta_s. The S-waves could well be the result of a final state formed from an s-quark anti-s-quark pair in a 0+ spin-parity state, such as the f0(980) meson. Data driven and theoretical estimates of the Bs decay rate into the CP+ final state J/psi f0(980) are given, when f0 -> pi+pi-. The S-wave contribution in J\psi\phi should be taken into account when determining beta_s by including a K+K- S-wave amplitude in the fit. This may change the central value of current results and will also increase the statistical uncertainty. Importantly, the J/psi f0(980) mode has been suggested as an alternative channel for measuring beta_s.
[ { "created": "Fri, 24 Sep 2010 20:11:26 GMT", "version": "v1" } ]
2011-04-08
[ [ "Stone", "Sheldon", "" ] ]
The CP Violating asymmetry in Bs mixing (beta_s) is one of the most promising measurements where physics beyond the Standard Model could be revealed. As such, analyses need to be subjected to great scrutiny. The mode Bs -> J/psi\phi has been used, and the mode Bs -> \phi \phi proposed for future measurements. These modes both have two vector particles in the final state and thus angular analyses must be used to disentangle the contributions from CP+ and CP- configurations. The angular distributions, however, could be distorted by the presence of S-waves masquerading as low mass K+K- pairs, that could result in erroneous values of beta_s. The S-waves could well be the result of a final state formed from an s-quark anti-s-quark pair in a 0+ spin-parity state, such as the f0(980) meson. Data driven and theoretical estimates of the Bs decay rate into the CP+ final state J/psi f0(980) are given, when f0 -> pi+pi-. The S-wave contribution in J\psi\phi should be taken into account when determining beta_s by including a K+K- S-wave amplitude in the fit. This may change the central value of current results and will also increase the statistical uncertainty. Importantly, the J/psi f0(980) mode has been suggested as an alternative channel for measuring beta_s.
1607.00810
Santosh Kumar Rai
Kasinath Das, Tianjun Li, S. Nandi, Santosh Kumar Rai
A new proposal for diphoton resonance from $E_6$ motivated extra $U(1)$
19 pages, 12 eps figures
null
null
HRI-RECAPP-2016-010, OSU-HEP-16-05
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose that the diphoton resonance signal indicated by the recent LHC data might also arise from the pair productions of vector-like heavy down-type quarks with mass around $750$ GeV and above. The vector-like quark decays into an ordinary light quark and a Standard Model singlet scalar. The subsequent decay of scalar singlet produces the diphoton excess. Both the vector-like quark and singlet scalars appear naturally in the $E_6$, and their masses can be in the TeV scale with a suitable choice of symmetry breaking pattern. The prediction of such a proposal would be to see an accompanying dijet signal at the same mass with similar cross section in the $2\gamma + 2j$ final state and two dijet resonances at the same mass for a $4j$ final state with a cross section, about 100 times larger. Both predictions can be tested easily as the luminosity accumulates in the upcoming runs of the LHC.
[ { "created": "Mon, 4 Jul 2016 10:26:42 GMT", "version": "v1" } ]
2016-07-05
[ [ "Das", "Kasinath", "" ], [ "Li", "Tianjun", "" ], [ "Nandi", "S.", "" ], [ "Rai", "Santosh Kumar", "" ] ]
We propose that the diphoton resonance signal indicated by the recent LHC data might also arise from the pair productions of vector-like heavy down-type quarks with mass around $750$ GeV and above. The vector-like quark decays into an ordinary light quark and a Standard Model singlet scalar. The subsequent decay of scalar singlet produces the diphoton excess. Both the vector-like quark and singlet scalars appear naturally in the $E_6$, and their masses can be in the TeV scale with a suitable choice of symmetry breaking pattern. The prediction of such a proposal would be to see an accompanying dijet signal at the same mass with similar cross section in the $2\gamma + 2j$ final state and two dijet resonances at the same mass for a $4j$ final state with a cross section, about 100 times larger. Both predictions can be tested easily as the luminosity accumulates in the upcoming runs of the LHC.
1910.03272
Danny Marfatia
Tao Han, Jiajun Liao, Hongkai Liu, Danny Marfatia
Nonstandard neutrino interactions at COHERENT, DUNE, T2HK and LHC
21 pages, 5 figures, 1 table. Published version
JHEP 1911:028 (2019)
10.1007/JHEP11(2019)028
PITT-PACC-1815
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study how nonstandard neutrino interactions (NSI) may be probed by a combination of coherent elastic neutrino-nucleus scattering, neutrino oscillation and collider data, from COHERENT, DUNE, T2HK and the high-luminosity (HL) LHC. We focus on NSI induced by a new flavored gauge boson $Z'$ in a generic anomaly-free ultraviolet-complete model. For $Z'$ masses above 10 GeV, the HL-LHC has the best sensitivity regardless of the flavor structure of the model. For masses between 0.01 GeV-10 GeV, current LHCb data and future COHERENT data have the best sensitivity unless the $Z'$ couplings to the first and second generation leptons are suppressed, in which case DUNE and T2HK have the best sensitivity. For $Z'$ masses between about 5 MeV-20 MeV, DUNE and T2HK have the best sensitivity. We also show how joint analyses of COHERENT and LHC data may constrain such models.
[ { "created": "Tue, 8 Oct 2019 08:42:12 GMT", "version": "v1" }, { "created": "Sun, 20 Oct 2019 08:09:49 GMT", "version": "v2" }, { "created": "Tue, 12 Nov 2019 02:32:44 GMT", "version": "v3" } ]
2019-11-13
[ [ "Han", "Tao", "" ], [ "Liao", "Jiajun", "" ], [ "Liu", "Hongkai", "" ], [ "Marfatia", "Danny", "" ] ]
We study how nonstandard neutrino interactions (NSI) may be probed by a combination of coherent elastic neutrino-nucleus scattering, neutrino oscillation and collider data, from COHERENT, DUNE, T2HK and the high-luminosity (HL) LHC. We focus on NSI induced by a new flavored gauge boson $Z'$ in a generic anomaly-free ultraviolet-complete model. For $Z'$ masses above 10 GeV, the HL-LHC has the best sensitivity regardless of the flavor structure of the model. For masses between 0.01 GeV-10 GeV, current LHCb data and future COHERENT data have the best sensitivity unless the $Z'$ couplings to the first and second generation leptons are suppressed, in which case DUNE and T2HK have the best sensitivity. For $Z'$ masses between about 5 MeV-20 MeV, DUNE and T2HK have the best sensitivity. We also show how joint analyses of COHERENT and LHC data may constrain such models.
hep-ph/9406274
Dirk Graudenz
Dirk Graudenz
One-Particle Inclusive Processes in Deeply Inelastic Lepton-Nucleon Scattering
20 pages (LaTex) + 4 pages of figures appended in the end of the file as a uuencoded postscript file, CERN-TH.7300/94
Nucl.Phys. B432 (1994) 351-376
10.1016/0550-3213(94)90606-8
null
hep-ph
null
The one-particle inclusive cross section in deeply inelastic lepton--nucleon scattering, expressed in terms of parton densities and fragmentation functions being differential in the invariant mass of the observed hadron and of the incoming nucleon, diverges if this invariant mass vanishes. This divergence can be traced back to the kinematical configuration where the parent parton of the observed hadron is emitted collinearly from the incoming parton of the QCD subprocess. By using the concept of ``fracture functions'', which has recently been introduced by Trentadue and Veneziano, it is possible to absorb this divergence in these new distribution functions as long as the observed hadron is not soft. This procedure allows the determination of a finite one-particle inclusive cross section in next-to-leading order QCD perturbation theory. We give details of the calculation and the explicit form of the bare fracture functions in terms of the renormalized ones.
[ { "created": "Fri, 10 Jun 1994 10:03:58 GMT", "version": "v1" } ]
2009-10-28
[ [ "Graudenz", "Dirk", "" ] ]
The one-particle inclusive cross section in deeply inelastic lepton--nucleon scattering, expressed in terms of parton densities and fragmentation functions being differential in the invariant mass of the observed hadron and of the incoming nucleon, diverges if this invariant mass vanishes. This divergence can be traced back to the kinematical configuration where the parent parton of the observed hadron is emitted collinearly from the incoming parton of the QCD subprocess. By using the concept of ``fracture functions'', which has recently been introduced by Trentadue and Veneziano, it is possible to absorb this divergence in these new distribution functions as long as the observed hadron is not soft. This procedure allows the determination of a finite one-particle inclusive cross section in next-to-leading order QCD perturbation theory. We give details of the calculation and the explicit form of the bare fracture functions in terms of the renormalized ones.
1007.3832
Shingo Kobayashi
Shingo Kobayashi. Michikazu Kobayashi, Yuki Kawaguchi, Muneto Nitta, and Masahito Ueda
Topological Influence between Monopoles and Vortices: a Possible Resolution of the Monopole Problem
4 pages, 3 figures
null
null
null
hep-ph astro-ph.CO cond-mat.other hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Grand unified theories of fundamental forces predict that magnetic monopoles are inevitable in the Universe because the second homotopy group of the order parameter manifold is $\mathbb{Z}$. We point out that monopoles can annihilate in pairs due to an influence of Alice strings. As a consequence, a monopole charge is charactarized by $\mathbb{Z}_2$ rather than $\mathbb{Z}$ if the Universe can accommodate Alice strings, which is the case of certain grand unified theories.
[ { "created": "Thu, 22 Jul 2010 09:10:48 GMT", "version": "v1" } ]
2010-07-29
[ [ "Kobayashi", "Shingo Kobayashi. Michikazu", "" ], [ "Kawaguchi", "Yuki", "" ], [ "Nitta", "Muneto", "" ], [ "Ueda", "Masahito", "" ] ]
Grand unified theories of fundamental forces predict that magnetic monopoles are inevitable in the Universe because the second homotopy group of the order parameter manifold is $\mathbb{Z}$. We point out that monopoles can annihilate in pairs due to an influence of Alice strings. As a consequence, a monopole charge is charactarized by $\mathbb{Z}_2$ rather than $\mathbb{Z}$ if the Universe can accommodate Alice strings, which is the case of certain grand unified theories.
hep-ph/0408265
Raymond F. Sawyer
R. F. Sawyer
"Classical" instabilities and "quantum" speed-up in the evolution of neutrino clouds
12 pages, 4 figures
null
null
null
hep-ph
null
We study some examples of collective behavior in neutrino clouds governed by the neutral-current neutrino-neutrino interaction. The standard equations for analyzing such systems are rederived in a two-step process: first, a replacement of the full interaction Hamiltonian with a "forward" Hamiltonian that contains only the momentum states that were initially occupied by a neutrino of one flavor or another; second, a factorization assumption that reduces the time evolution problem to the solution of coupled equations for the expectations of various bilinear forms in the neutrino fields. We designate the latter as the "classical" equations. We analyze some solutions of these equations in cases in which the initial momentum and flavor distributions of neutrinos are strongly anisotropic in space. In some cases we find an instability that leads to rapid evolution of the flavor-angle distribution, even when it is seeded by a very small initial flavor mixing (or alternatively by a very small neutrino mass$^2$ term). Turning to the more complete case in which we do not assume the classical factorization, but instead solve for the evolution under the influence of the full "forward" Hamiltonian, we find the possibility of rapid evolution, under our definition, even when there is no seeding from conventional neutrino mixing.
[ { "created": "Tue, 24 Aug 2004 21:56:49 GMT", "version": "v1" } ]
2007-05-23
[ [ "Sawyer", "R. F.", "" ] ]
We study some examples of collective behavior in neutrino clouds governed by the neutral-current neutrino-neutrino interaction. The standard equations for analyzing such systems are rederived in a two-step process: first, a replacement of the full interaction Hamiltonian with a "forward" Hamiltonian that contains only the momentum states that were initially occupied by a neutrino of one flavor or another; second, a factorization assumption that reduces the time evolution problem to the solution of coupled equations for the expectations of various bilinear forms in the neutrino fields. We designate the latter as the "classical" equations. We analyze some solutions of these equations in cases in which the initial momentum and flavor distributions of neutrinos are strongly anisotropic in space. In some cases we find an instability that leads to rapid evolution of the flavor-angle distribution, even when it is seeded by a very small initial flavor mixing (or alternatively by a very small neutrino mass$^2$ term). Turning to the more complete case in which we do not assume the classical factorization, but instead solve for the evolution under the influence of the full "forward" Hamiltonian, we find the possibility of rapid evolution, under our definition, even when there is no seeding from conventional neutrino mixing.
hep-ph/0509303
Lin Li
Gang Hao, Lin Li, Cong-Feng Qiao
$D_s$ Asymmetry in Photoproduction
4 pages, talk presented by I. Caprini at the International Conference on QCD and Hadronic Physics, June 16-20 2005, Beijing
Int.J.Mod.Phys.A21:893-896,2006
10.1142/S0217751X06032253
null
hep-ph
null
By adopting two models of strange and antistrange quark distributions inside nucleon, the light-cone meson-baryon fluctuation model and the effective chiral quark model, we calculate the $D_s^+ - D_s^-$ asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We find that the effect of asymmetry of strange sea to the $D_s$ asymmetry is considerable and depending on the different models. Therefore, we expect that with the further study in electroproduction, e.g. at HERA and CEBAF, the experimental measurements on the $D_s^+ - D_s^-$ asymmetry may impose a strong restriction on the strange-antistrange distribution asymmetry models.
[ { "created": "Tue, 27 Sep 2005 12:08:47 GMT", "version": "v1" } ]
2016-09-06
[ [ "Hao", "Gang", "" ], [ "Li", "Lin", "" ], [ "Qiao", "Cong-Feng", "" ] ]
By adopting two models of strange and antistrange quark distributions inside nucleon, the light-cone meson-baryon fluctuation model and the effective chiral quark model, we calculate the $D_s^+ - D_s^-$ asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We find that the effect of asymmetry of strange sea to the $D_s$ asymmetry is considerable and depending on the different models. Therefore, we expect that with the further study in electroproduction, e.g. at HERA and CEBAF, the experimental measurements on the $D_s^+ - D_s^-$ asymmetry may impose a strong restriction on the strange-antistrange distribution asymmetry models.
2407.02399
John McDonald
John McDonald
Vector-like Quark Stabilised Higgs Inflation: Implications for Particle Phenomenology, Primordial Gravitational Waves and the Hubble Tension
15 pages, 10 figures. Additional references and discussion
null
null
null
hep-ph astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
The Standard Model Higgs potential is very likely to be metastable, in which case Higgs Inflation is likely to require an extension in order to stabilise the potential. Here we consider stabilisation by adding $n_{Q} \leq 3$ Vector-Like Quarks (VLQs) of mass $m_{Q}$: $T$ vector quarks transforming as $({\bf 3}, {\bf 1}, 2/3)$ and $B$ vector quarks transforming as $({\bf 3}, {\bf 1}, -1/3)$. Requiring stability of the finite-temperature effective potential, and assuming $m_{t}$ equals its mean value, we find that the upper bounds on $m_{Q}$ for $T$ quarks are 5.8 TeV (for $n_{Q} = 2$) and 55 TeV (for $n_{Q} = 3$). The corresponding absolute stability upper bounds are 4.4 TeV and 29 TeV. Small upper bounds are obtained for $B$ quarks. For renormalisation in the Einstein frame (Prescription I) the predictions are almost indistinguishable from the classical values: $n_s = 0.966$ and $r = 3.3 \times 10^{-3}$. Renormalisation in the Jordan frame (Prescription II) predicts larger values of $n_{s}$ and $r$, with $n_{s}$ generally in the range 0.980 to 0.990 and $r$ of the order of 0.01. The predicted range of $n_{s}$ is consistent with the CMB range obtained in Hubble tension solutions which modify the sound horizon at decoupling, whilst the predicted values of $r$ will be easily observable by forthcoming CMB experiments. The observational upper bound on $r$ generally imposes a stronger constraint on $m_{Q}$, with the $T$ quark upper bound equal to 2.4 TeV for $n_{Q} = 2$ and 13 TeV for $n_{Q} = 3$. We conclude that VLQ-stabilised Higgs Inflation with Prescription II renormalisation favours 1-10 TeV vector-like quarks that will be accessible to future colliders, and predicts a tensor-to-scalar ratio that will be observable in forthcoming CMB experiments and values of $n_{s}$ that favour an early-time solution to the Hubble tension.
[ { "created": "Tue, 2 Jul 2024 16:16:57 GMT", "version": "v1" }, { "created": "Mon, 8 Jul 2024 17:15:47 GMT", "version": "v2" } ]
2024-07-09
[ [ "McDonald", "John", "" ] ]
The Standard Model Higgs potential is very likely to be metastable, in which case Higgs Inflation is likely to require an extension in order to stabilise the potential. Here we consider stabilisation by adding $n_{Q} \leq 3$ Vector-Like Quarks (VLQs) of mass $m_{Q}$: $T$ vector quarks transforming as $({\bf 3}, {\bf 1}, 2/3)$ and $B$ vector quarks transforming as $({\bf 3}, {\bf 1}, -1/3)$. Requiring stability of the finite-temperature effective potential, and assuming $m_{t}$ equals its mean value, we find that the upper bounds on $m_{Q}$ for $T$ quarks are 5.8 TeV (for $n_{Q} = 2$) and 55 TeV (for $n_{Q} = 3$). The corresponding absolute stability upper bounds are 4.4 TeV and 29 TeV. Small upper bounds are obtained for $B$ quarks. For renormalisation in the Einstein frame (Prescription I) the predictions are almost indistinguishable from the classical values: $n_s = 0.966$ and $r = 3.3 \times 10^{-3}$. Renormalisation in the Jordan frame (Prescription II) predicts larger values of $n_{s}$ and $r$, with $n_{s}$ generally in the range 0.980 to 0.990 and $r$ of the order of 0.01. The predicted range of $n_{s}$ is consistent with the CMB range obtained in Hubble tension solutions which modify the sound horizon at decoupling, whilst the predicted values of $r$ will be easily observable by forthcoming CMB experiments. The observational upper bound on $r$ generally imposes a stronger constraint on $m_{Q}$, with the $T$ quark upper bound equal to 2.4 TeV for $n_{Q} = 2$ and 13 TeV for $n_{Q} = 3$. We conclude that VLQ-stabilised Higgs Inflation with Prescription II renormalisation favours 1-10 TeV vector-like quarks that will be accessible to future colliders, and predicts a tensor-to-scalar ratio that will be observable in forthcoming CMB experiments and values of $n_{s}$ that favour an early-time solution to the Hubble tension.
hep-ph/0601244
Steven D. Bass
R.J. Crewther, S.D. Bass, F.M. Steffens and A.W. Thomas
Decoupling heavy particles simultaneously
6 pages, 4 figures. Talk presented at the "QCD Down Under" Workshop, Barossa Valley and Adelaide, Australia, 10-19 March 2004, with ref 8 now linked to hep-ph/0507278
Nucl.Phys.Proc.Suppl.141:159-164,2005
10.1016/j.nuclphysbps.2004.12.024
null
hep-ph
null
The renormalization group is extended to cases where several heavy particles are decoupled at the same time. This involves large logarithms which are scale-invariant and so cannot be eliminated by a change of renormalization scheme. A set of scale-invariant running couplings, one for each heavy particle, is constructed without reference to intermediate thresholds. The entire heavy-quark correction to the axial charge of the weak neutral current is derived to next-to-leading order, and checked in leading order by evaluating diagrams explicitly. The mechanism for cancelling contributions from the top and bottom quarks in the equal-mass limit is surprisingly non-trivial.
[ { "created": "Mon, 30 Jan 2006 09:20:18 GMT", "version": "v1" } ]
2010-03-26
[ [ "Crewther", "R. J.", "" ], [ "Bass", "S. D.", "" ], [ "Steffens", "F. M.", "" ], [ "Thomas", "A. W.", "" ] ]
The renormalization group is extended to cases where several heavy particles are decoupled at the same time. This involves large logarithms which are scale-invariant and so cannot be eliminated by a change of renormalization scheme. A set of scale-invariant running couplings, one for each heavy particle, is constructed without reference to intermediate thresholds. The entire heavy-quark correction to the axial charge of the weak neutral current is derived to next-to-leading order, and checked in leading order by evaluating diagrams explicitly. The mechanism for cancelling contributions from the top and bottom quarks in the equal-mass limit is surprisingly non-trivial.
1710.07164
Li-Sheng Geng
Xiu-Lei Ren, Xi-Zhe Ling, and Li-Sheng Geng
Pion-nucleon sigma term revisited in covariant baryon chiral perturbation theory
7 pages, 2 figures, 2 tables
null
10.1016/j.physletb.2018.05.063
null
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the latest $N_f=2+1+1$ and $N_f=2$ ETMC lattice QCD simulations of the nucleon masses and extract the pion-nucleon sigma term utilizing the Feynman-Hellmann theorem in SU(2) baryon chiral perturbation theory with the extended-on-mass-shell scheme. We find that the lattice QCD data can be described quite well already at the next-to-next-to-leading order. The overall picture remains essentially the same at the next-to-next-to-next-to-leading order. Our final result is $\sigma_{\pi N}=50.2(1.2)(2.0)$ MeV, or equivalently, $f_{u/d}^N=0.0535(13)(21)$, where the first uncertainty is statistical and second is theoretical originated from chiral truncations, which is in agreement with that determined previously from the $N_f=2+1$ and $N_f=2$ lattice QCD data and that determined by the Cheng-Dashen theorem. In addition, we show that the inclusion of the virtual $\Delta(1232)$ does not change qualitatively our results.
[ { "created": "Thu, 19 Oct 2017 14:44:39 GMT", "version": "v1" }, { "created": "Thu, 12 Jul 2018 14:39:49 GMT", "version": "v2" } ]
2018-07-13
[ [ "Ren", "Xiu-Lei", "" ], [ "Ling", "Xi-Zhe", "" ], [ "Geng", "Li-Sheng", "" ] ]
We study the latest $N_f=2+1+1$ and $N_f=2$ ETMC lattice QCD simulations of the nucleon masses and extract the pion-nucleon sigma term utilizing the Feynman-Hellmann theorem in SU(2) baryon chiral perturbation theory with the extended-on-mass-shell scheme. We find that the lattice QCD data can be described quite well already at the next-to-next-to-leading order. The overall picture remains essentially the same at the next-to-next-to-next-to-leading order. Our final result is $\sigma_{\pi N}=50.2(1.2)(2.0)$ MeV, or equivalently, $f_{u/d}^N=0.0535(13)(21)$, where the first uncertainty is statistical and second is theoretical originated from chiral truncations, which is in agreement with that determined previously from the $N_f=2+1$ and $N_f=2$ lattice QCD data and that determined by the Cheng-Dashen theorem. In addition, we show that the inclusion of the virtual $\Delta(1232)$ does not change qualitatively our results.
2109.09752
Melissa van Beekveld
Melissa van Beekveld, Leonardo Vernazza, Chris D. White
Threshold resummation of new partonic channels at next-to-leading power
null
null
10.1007/JHEP12(2021)087
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
Collider observables involving heavy particles are subject to large logarithmic terms near threshold, which must be summed to all orders in perturbation theory to obtain sensible results. Relatively recently, this resummation has been extended to next-to-leading power in the threshold variable, using a variety of approaches. In this paper, we consider partonic channels that turn on only at next-to-leading power, and show that it is possible to resum leading logarithms using well-established diagrammatic techniques in Quantum Chromodynamics. We first consider deep inelastic scattering, where we reproduce the results of a recent study using an effective theory approach. Next, we consider the quark-gluon channel in both Drell-Yan and Higgs boson production, showing that an explicit all-order form for the leading logarithmic partonic cross section can be obtained. Our results agree with previous conjectures based on fixed-order results.
[ { "created": "Mon, 20 Sep 2021 18:00:02 GMT", "version": "v1" } ]
2022-01-05
[ [ "van Beekveld", "Melissa", "" ], [ "Vernazza", "Leonardo", "" ], [ "White", "Chris D.", "" ] ]
Collider observables involving heavy particles are subject to large logarithmic terms near threshold, which must be summed to all orders in perturbation theory to obtain sensible results. Relatively recently, this resummation has been extended to next-to-leading power in the threshold variable, using a variety of approaches. In this paper, we consider partonic channels that turn on only at next-to-leading power, and show that it is possible to resum leading logarithms using well-established diagrammatic techniques in Quantum Chromodynamics. We first consider deep inelastic scattering, where we reproduce the results of a recent study using an effective theory approach. Next, we consider the quark-gluon channel in both Drell-Yan and Higgs boson production, showing that an explicit all-order form for the leading logarithmic partonic cross section can be obtained. Our results agree with previous conjectures based on fixed-order results.
hep-ph/0103049
Juergen Berges
G. Aarts and J. Berges (Heidelberg)
Nonequilibrium time evolution of the spectral function in quantum field theory
20 pages with 6 eps figures, explanation and references added; to appear in Phys.Rev.D
Phys.Rev.D64:105010,2001
10.1103/PhysRevD.64.105010
HD-THEP-01-11
hep-ph hep-th nucl-th
null
Transport or kinetic equations are often derived assuming a quasi-particle (on-shell) representation of the spectral function. We investigate this assumption using a three-loop approximation of the 2PI effective action in real time, without a gradient expansion or on-shell approximation. For a scalar field in 1+1 dimensions the nonlinear evolution, including the integration over memory kernels, can be solved numerically. We find that a spectral function approximately described by a nonzero width emerges dynamically. During the nonequilibrium time evolution the Wigner transformed spectral function is slowly varying, even in presence of strong qualitative changes in the effective particle distribution. These results may be used to make further analytical progress towards a quantum Boltzmann equation including off-shell effects and a nonzero width.
[ { "created": "Mon, 5 Mar 2001 14:22:36 GMT", "version": "v1" }, { "created": "Thu, 2 Aug 2001 13:32:30 GMT", "version": "v2" } ]
2010-02-04
[ [ "Aarts", "G.", "", "Heidelberg" ], [ "Berges", "J.", "", "Heidelberg" ] ]
Transport or kinetic equations are often derived assuming a quasi-particle (on-shell) representation of the spectral function. We investigate this assumption using a three-loop approximation of the 2PI effective action in real time, without a gradient expansion or on-shell approximation. For a scalar field in 1+1 dimensions the nonlinear evolution, including the integration over memory kernels, can be solved numerically. We find that a spectral function approximately described by a nonzero width emerges dynamically. During the nonequilibrium time evolution the Wigner transformed spectral function is slowly varying, even in presence of strong qualitative changes in the effective particle distribution. These results may be used to make further analytical progress towards a quantum Boltzmann equation including off-shell effects and a nonzero width.
hep-ph/0305295
Osamu Yasuda
Osamu Yasuda
Parameter degeneracy and reactor experiments
8 pages, 12 figures, uses ws-procs9x6.cls. To appear in the proceedings of 4th Workshop on Neutrino Oscillations and their Origin (NOON2003), Kanazawa, Japan, 10-14 Feb 2003
null
null
null
hep-ph
null
Degeneracies of the neutrino oscillation parameters are explained using the $\sin^22\theta_{13}$--$s^2_{23}$ plane. Measurements of $\sin^22\theta_{13}$ by reactor experiments are free from the parameter degeneracies which occur in accelerator appearance experiments, and reactor experiments play a role complementary to accelerator experiments. It is shown that the reactor measurement may be able to resolve the degeneracy in $\theta_{23}$ if $\sin^22\theta_{13}$ and $\cos^22\theta_{23}$ are relatively large.
[ { "created": "Tue, 27 May 2003 08:35:36 GMT", "version": "v1" } ]
2007-05-23
[ [ "Yasuda", "Osamu", "" ] ]
Degeneracies of the neutrino oscillation parameters are explained using the $\sin^22\theta_{13}$--$s^2_{23}$ plane. Measurements of $\sin^22\theta_{13}$ by reactor experiments are free from the parameter degeneracies which occur in accelerator appearance experiments, and reactor experiments play a role complementary to accelerator experiments. It is shown that the reactor measurement may be able to resolve the degeneracy in $\theta_{23}$ if $\sin^22\theta_{13}$ and $\cos^22\theta_{23}$ are relatively large.
hep-ph/0506191
Claudio Nassif
Claudio Nassif and P.R. Silva
Quantum Electro and Chromodynamics treated by Thompson's heuristic approach
RevTex, 25 pages, no figures
Int.J.Mod.Phys. A21 (2006) 3809-3824
10.1142/S0217751X06031508
null
hep-ph
null
In this work we apply Thompson's method (of the dimensions and scales) to study some features of the Quantum Electro and Chromodynamics. This heuristic method can be considered as a simple and alternative way to the Renormalisation Group (R.G.) approach and when applied to QED-lagrangian is able to obtain in a first approximation both the running coupling constant behavior of alpha(mu) and the mass m(mu).The calculations are evaluated just at d_c=4, where d_c is the upper critical dimension of the problem, so that we obtain the logarithmic behavior both for the coupling alpha and the excess of mass Delta m on the energy scale mu. Although our results are well-known in the vast literature of field theories,it seems that one of the advantages of Thompson's method, beyond its simplicity is that it is able to extract directly from QED-lagrangian the physical (finite) behavior of alpha(mu) and m(mu), bypassing hard problems of divergences which normally appear in the conventional renormalisation schemes applied to field theories like QED. Quantum Chromodynamics (QCD) is also treated by the present method in order to obtain the quark condensate value. Besides this, the method is also able to evaluate the vacuum pressure at the boundary of the nucleon. This is done by assumming a step function behavior for the running coupling constant of the QCD, which fits nicely to some quantities related to the strong interaction evaluated through the MIT-bag model.
[ { "created": "Mon, 20 Jun 2005 01:46:14 GMT", "version": "v1" } ]
2015-06-25
[ [ "Nassif", "Claudio", "" ], [ "Silva", "P. R.", "" ] ]
In this work we apply Thompson's method (of the dimensions and scales) to study some features of the Quantum Electro and Chromodynamics. This heuristic method can be considered as a simple and alternative way to the Renormalisation Group (R.G.) approach and when applied to QED-lagrangian is able to obtain in a first approximation both the running coupling constant behavior of alpha(mu) and the mass m(mu).The calculations are evaluated just at d_c=4, where d_c is the upper critical dimension of the problem, so that we obtain the logarithmic behavior both for the coupling alpha and the excess of mass Delta m on the energy scale mu. Although our results are well-known in the vast literature of field theories,it seems that one of the advantages of Thompson's method, beyond its simplicity is that it is able to extract directly from QED-lagrangian the physical (finite) behavior of alpha(mu) and m(mu), bypassing hard problems of divergences which normally appear in the conventional renormalisation schemes applied to field theories like QED. Quantum Chromodynamics (QCD) is also treated by the present method in order to obtain the quark condensate value. Besides this, the method is also able to evaluate the vacuum pressure at the boundary of the nucleon. This is done by assumming a step function behavior for the running coupling constant of the QCD, which fits nicely to some quantities related to the strong interaction evaluated through the MIT-bag model.
hep-ph/9905485
Alexei A. Pivovarov
A.A.Pivovarov
Two-loop corrections to the correlator of tensor currents in gluodynamics
10 pages, latex, no figures
Phys.Atom.Nucl.63:1646-1649,2000; Yad.Fiz.63N9:1734-1737,2000
10.1134/1.1312900
MZ-TH/99-21
hep-ph hep-ex
null
Results of evaluating the leading order $\alpha_s$ corrections to the correlator of tensor currents in pure gluodynamics are presented. These corrections to the parton result for the correlator are not large numerically that allows one to use perturbation theory for the analysis of the resonance spectrum within the sum rules method.
[ { "created": "Wed, 26 May 1999 07:01:20 GMT", "version": "v1" } ]
2014-11-17
[ [ "Pivovarov", "A. A.", "" ] ]
Results of evaluating the leading order $\alpha_s$ corrections to the correlator of tensor currents in pure gluodynamics are presented. These corrections to the parton result for the correlator are not large numerically that allows one to use perturbation theory for the analysis of the resonance spectrum within the sum rules method.
1911.03481
Giovanni Grilli di Cortona
Marcin Badziak, Giovanni Grilli di Cortona and Keisuke Harigaya
Natural Twin Neutralino Dark Matter
6 pages, 3 figures + supplemental material
Phys. Rev. Lett. 124, 121803 (2020)
10.1103/PhysRevLett.124.121803
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Supersymmetric Twin Higgs models have a discrete symmetry for which each Standard Model particle and its supersymmetric partner have a corresponding state that transforms under a mirror Standard Model gauge group. This framework is able to accommodate the non-discovery of new particles at the LHC with the naturalness of the electroweak scale. We point out that supersymmetric Twin Higgs models also provide a natural dark matter candidate. We investigate the possibility that a twin bino-like state is the Lightest Supersymmetric Particle and find that its freeze-out abundance can explain the observed dark matter abundance without fine-tuning the mass spectrum of the theory. Most of the viable parameter space can be probed by future dark matter direct detection experiments and the LHC searches for staus and higgsinos which may involve displaced vertices.
[ { "created": "Fri, 8 Nov 2019 19:00:03 GMT", "version": "v1" }, { "created": "Wed, 22 Apr 2020 19:39:21 GMT", "version": "v2" } ]
2020-04-24
[ [ "Badziak", "Marcin", "" ], [ "di Cortona", "Giovanni Grilli", "" ], [ "Harigaya", "Keisuke", "" ] ]
Supersymmetric Twin Higgs models have a discrete symmetry for which each Standard Model particle and its supersymmetric partner have a corresponding state that transforms under a mirror Standard Model gauge group. This framework is able to accommodate the non-discovery of new particles at the LHC with the naturalness of the electroweak scale. We point out that supersymmetric Twin Higgs models also provide a natural dark matter candidate. We investigate the possibility that a twin bino-like state is the Lightest Supersymmetric Particle and find that its freeze-out abundance can explain the observed dark matter abundance without fine-tuning the mass spectrum of the theory. Most of the viable parameter space can be probed by future dark matter direct detection experiments and the LHC searches for staus and higgsinos which may involve displaced vertices.
2306.16477
Leonardo Badurina
Leonardo Badurina, Ankit Beniwal, Christopher McCabe
Super-Nyquist ultralight dark matter searches with broadband atom gradiometers
28 pages plus appendices, 12 figures. v2: matches published version
Phys. Rev. D 108, 083016 (2023)
10.1103/PhysRevD.108.083016
KCL-PH-TH/2023-30, AION-REPORT/2023-05
hep-ph astro-ph.CO physics.atom-ph
http://creativecommons.org/licenses/by/4.0/
Atom gradiometers have emerged as compelling broadband probes of scalar ultralight dark matter (ULDM) candidates that oscillate with frequencies between approximately $10^{-2}$ Hz and $10^3$ Hz. ULDM signals with frequencies greater than $\sim 1$ Hz exceed the expected Nyquist frequency of atom gradiometers, and so are affected by aliasing and related phenomena, including signal folding and spectral distortion. To facilitate the discovery of super-Nyquist ULDM signals, in this work we investigate the impact of these effects on parameter reconstruction using a robust likelihood-based framework. We demonstrate that accurate reconstruction of ULDM parameters can be achieved as long as the experimental frequency resolution is larger than the ULDM signal linewidth. Notably, as ULDM candidates whose frequencies differ by integer multiples of the sampling frequency are identified at the same aliased frequency, our discovery analysis recovers discrete islands in parameter space. Our study represents the first comprehensive exploration of aliasing in the context of dark matter direct detection and paves the way for enhanced ULDM detection strategies with atom gradiometers.
[ { "created": "Wed, 28 Jun 2023 18:06:29 GMT", "version": "v1" }, { "created": "Fri, 13 Oct 2023 00:37:58 GMT", "version": "v2" } ]
2023-10-16
[ [ "Badurina", "Leonardo", "" ], [ "Beniwal", "Ankit", "" ], [ "McCabe", "Christopher", "" ] ]
Atom gradiometers have emerged as compelling broadband probes of scalar ultralight dark matter (ULDM) candidates that oscillate with frequencies between approximately $10^{-2}$ Hz and $10^3$ Hz. ULDM signals with frequencies greater than $\sim 1$ Hz exceed the expected Nyquist frequency of atom gradiometers, and so are affected by aliasing and related phenomena, including signal folding and spectral distortion. To facilitate the discovery of super-Nyquist ULDM signals, in this work we investigate the impact of these effects on parameter reconstruction using a robust likelihood-based framework. We demonstrate that accurate reconstruction of ULDM parameters can be achieved as long as the experimental frequency resolution is larger than the ULDM signal linewidth. Notably, as ULDM candidates whose frequencies differ by integer multiples of the sampling frequency are identified at the same aliased frequency, our discovery analysis recovers discrete islands in parameter space. Our study represents the first comprehensive exploration of aliasing in the context of dark matter direct detection and paves the way for enhanced ULDM detection strategies with atom gradiometers.
hep-ph/9807264
Chris Quigg
Raj Gandhi, Chris Quigg, Mary Hall Reno, Ina Sarcevic
Neutrino Interactions at Ultrahigh Energies
32 pages, 11 figures, uses RevTeX and boxedeps
Phys.Rev.D58:093009,1998
10.1103/PhysRevD.58.093009
FERMILAB-PUB-98/087-T
hep-ph astro-ph
null
We report new calculations of the cross sections for deeply inelastic neutrino-nucleon scattering at neutrino energies between $10^{9}\ev$ and $10^{21}\ev$. We compare with results in the literature and assess the reliability of our predictions. For completeness, we briefly review the cross sections for neutrino interactions with atomic electrons, emphasizing the role of the $W$-boson resonance in $\bar{\nu}_{e}e$ interactions for neutrino energies in the neighborhood of $6.3\pev$. Adopting model predictions for extraterrestrial neutrino fluxes from active galactic nuclei, gamma-ray bursters, and the collapse of topological defects, we estimate event rates in large-volume water \v{C}erenkov detectors and large-area ground arrays.
[ { "created": "Mon, 6 Jul 1998 22:03:52 GMT", "version": "v1" } ]
2009-05-05
[ [ "Gandhi", "Raj", "" ], [ "Quigg", "Chris", "" ], [ "Reno", "Mary Hall", "" ], [ "Sarcevic", "Ina", "" ] ]
We report new calculations of the cross sections for deeply inelastic neutrino-nucleon scattering at neutrino energies between $10^{9}\ev$ and $10^{21}\ev$. We compare with results in the literature and assess the reliability of our predictions. For completeness, we briefly review the cross sections for neutrino interactions with atomic electrons, emphasizing the role of the $W$-boson resonance in $\bar{\nu}_{e}e$ interactions for neutrino energies in the neighborhood of $6.3\pev$. Adopting model predictions for extraterrestrial neutrino fluxes from active galactic nuclei, gamma-ray bursters, and the collapse of topological defects, we estimate event rates in large-volume water \v{C}erenkov detectors and large-area ground arrays.
hep-ph/0104160
Yukinori Nagatani
Yukinori Nagatani (Yukawa Inst., Kyoto Univ.)
Electroweak Domain Wall by Hawking Radiation: Baryogenesis and Dark Matter from Several Hundred kg Black Holes
28 pages, 7 figures, LaTeX2e with graphicx macro
null
null
YITP-01-28
hep-ph astro-ph
null
We show that a spherical electroweak domain wall is formed around a small black hole and this is a general property of the Hawking radiation in the vacuum of the Standard Model. The wall appears not only for the first order phase transition in the electroweak theory but also for the second order one because the black hole heats up its neighborhood locally by the Hawking radiation in any case. We propose a model for unifying the origin of the baryon number and the cold dark matter in our universe by using properties of the primordial black hole with a mass of several hundred kilograms. The interaction between our wall and the Hawking-radiated-particles can create a baryon number which is proportional to the mass of the black hole as well as the CP broken phase in the extension of the Standard Model. Our model can explain both the baryon-entropy ratio B/S \sim 10^{-10} and the energy density of the dark matter, provided that the following three conditions are satisfied: (i) the primordial black holes dominate in the early universe, (ii) the CP broken phase in the wall is in the order of one and (iii) any black hole leaves a stable remnant with a Planck mass after its evaporation. Our model also predicts a cosmological graviton background with a peak-energy 120 \sim 280 eV in the present universe.
[ { "created": "Tue, 17 Apr 2001 14:30:17 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nagatani", "Yukinori", "", "Yukawa Inst., Kyoto Univ." ] ]
We show that a spherical electroweak domain wall is formed around a small black hole and this is a general property of the Hawking radiation in the vacuum of the Standard Model. The wall appears not only for the first order phase transition in the electroweak theory but also for the second order one because the black hole heats up its neighborhood locally by the Hawking radiation in any case. We propose a model for unifying the origin of the baryon number and the cold dark matter in our universe by using properties of the primordial black hole with a mass of several hundred kilograms. The interaction between our wall and the Hawking-radiated-particles can create a baryon number which is proportional to the mass of the black hole as well as the CP broken phase in the extension of the Standard Model. Our model can explain both the baryon-entropy ratio B/S \sim 10^{-10} and the energy density of the dark matter, provided that the following three conditions are satisfied: (i) the primordial black holes dominate in the early universe, (ii) the CP broken phase in the wall is in the order of one and (iii) any black hole leaves a stable remnant with a Planck mass after its evaporation. Our model also predicts a cosmological graviton background with a peak-energy 120 \sim 280 eV in the present universe.
hep-ph/0209328
Grzegorz Wilk
F.O.Duraes, F.S.Navarra and G.Wilk
Leading particles and diffractive spectra in the Interacting Gluon Model
Presented at Diffraction2002, Alushta, Crimea (Ukraina), August 31 - September 5, 2002. To be published by Kluwer Academic Publishers (2003) (necessary style files attached). Rewritten according to the Kluwer specifications
null
null
null
hep-ph nucl-th
null
We discuss the leading particle spectra and diffractive mass spectra from the novel point of view, namely by treating them as particular examples of the general energy flow phenomena taking place in the multiparticle production processes. We argue that they show a high degree of universality what allows for their simple description in terms of the Interacting Gluon Model developed by us some time ago.
[ { "created": "Fri, 27 Sep 2002 07:30:31 GMT", "version": "v1" }, { "created": "Mon, 23 Dec 2002 11:18:05 GMT", "version": "v2" } ]
2007-05-23
[ [ "Duraes", "F. O.", "" ], [ "Navarra", "F. S.", "" ], [ "Wilk", "G.", "" ] ]
We discuss the leading particle spectra and diffractive mass spectra from the novel point of view, namely by treating them as particular examples of the general energy flow phenomena taking place in the multiparticle production processes. We argue that they show a high degree of universality what allows for their simple description in terms of the Interacting Gluon Model developed by us some time ago.
1201.2699
Kfir Blum
Kfir Blum, Aielet Efrati, Yuval Grossman, Yosef Nir, Antonio Riotto
Asymmetric Higgsino Dark Matter
5 pages, 2 figures
null
10.1103/PhysRevLett.109.051302
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the supersymmetric framework, a higgsino asymmetry exists in the universe before the electroweak phase transition. We investigate whether the higgsino is a viable asymmetric dark matter candidate. We find that this is indeed possible. The gauginos, squarks and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the higgsinos. The temperature of the electroweak phase transition must be in the (1-10) GeV range.
[ { "created": "Thu, 12 Jan 2012 22:39:00 GMT", "version": "v1" } ]
2013-05-30
[ [ "Blum", "Kfir", "" ], [ "Efrati", "Aielet", "" ], [ "Grossman", "Yuval", "" ], [ "Nir", "Yosef", "" ], [ "Riotto", "Antonio", "" ] ]
In the supersymmetric framework, a higgsino asymmetry exists in the universe before the electroweak phase transition. We investigate whether the higgsino is a viable asymmetric dark matter candidate. We find that this is indeed possible. The gauginos, squarks and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the higgsinos. The temperature of the electroweak phase transition must be in the (1-10) GeV range.
hep-ph/0309295
Werner Vogelsang
Werner Vogelsang
Some News on Spin Physics
14 pages, LaTeX, 9 figures as eps files. Invited plenary talk presented at the "XIth International Workshop on Deep Inelastic Scattering (DIS 2003)", St. Petersburg, Russia, April 23-27, 2003
null
null
BNL-NT-03/28, RBRC-338
hep-ph
null
We briefly review some of the recent developments in QCD spin physics.
[ { "created": "Thu, 25 Sep 2003 18:03:59 GMT", "version": "v1" } ]
2007-05-23
[ [ "Vogelsang", "Werner", "" ] ]
We briefly review some of the recent developments in QCD spin physics.
1212.4814
Peter Watson
Peter Watson, Hugo Reinhardt (Tuebingen U.)
Gap and Bethe-Salpeter equations in Coulomb gauge
8 pages, 5 figures, talk presented at "Quark Confinement and the Hadron Spectrum X", Munich, October 8-12, 2012
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by-nc-sa/3.0/
I will discuss the gap and Bethe-Salpeter equations for quantum chromodynamics in Coulomb gauge under a leading order truncation scheme. Within this scheme, the role of charge conservation and the cancellation of infrared divergences becomes particularly clear. The quark gap equation exhibits not only chiral symmetry breaking, but explicitly reproduces the heavy quark limit. The corresponding gluon equation has a massive solution with interesting nonperturbative renormalization properties. I will further discuss various aspects of the Bethe-Salpeter equation for pseudoscalar and vector mesons with arbitrary quark masses and present numerical results for the meson masses and leptonic decay constants.
[ { "created": "Wed, 19 Dec 2012 20:18:40 GMT", "version": "v1" } ]
2012-12-20
[ [ "Watson", "Peter", "", "Tuebingen U." ], [ "Reinhardt", "Hugo", "", "Tuebingen U." ] ]
I will discuss the gap and Bethe-Salpeter equations for quantum chromodynamics in Coulomb gauge under a leading order truncation scheme. Within this scheme, the role of charge conservation and the cancellation of infrared divergences becomes particularly clear. The quark gap equation exhibits not only chiral symmetry breaking, but explicitly reproduces the heavy quark limit. The corresponding gluon equation has a massive solution with interesting nonperturbative renormalization properties. I will further discuss various aspects of the Bethe-Salpeter equation for pseudoscalar and vector mesons with arbitrary quark masses and present numerical results for the meson masses and leptonic decay constants.
hep-ph/9302304
Lluis Ametller
Ll. Ametller, A. Bramon and E. Mass\'o
The $\pi^0\to e^+e^-$ and $\eta\to \mu^+ \mu^-$ Decays Revisited
10 pages, LATEX (revised version for recent experimental data)
Phys.Rev. D48 (1993) 3388-3391
10.1103/PhysRevD.48.3388
UAB-FT-300/93
hep-ph
null
The rare $\pi^0 \to e^+e^-$ and $\eta \to \mu^+\mu^-$ decays are calculated in different schemes, which are seen to be essentially equivalent to and produce the same results as conventional Vector-Meson Dominance. We obtain the theoretical predictions $B(\pi^0 \to e^+e^-) = (6.41 \pm 0.19)\times 10^{-8}$ and $B(\eta \to \mu^+\mu^-) = (1.14 +0.06 -0.03) \times 10^{-5}$ in agreement with recent experimental data.
[ { "created": "Wed, 24 Feb 1993 17:10:17 GMT", "version": "v1" }, { "created": "Fri, 5 Mar 1993 09:58:39 GMT", "version": "v2" } ]
2009-10-22
[ [ "Ametller", "Ll.", "" ], [ "Bramon", "A.", "" ], [ "Massó", "E.", "" ] ]
The rare $\pi^0 \to e^+e^-$ and $\eta \to \mu^+\mu^-$ decays are calculated in different schemes, which are seen to be essentially equivalent to and produce the same results as conventional Vector-Meson Dominance. We obtain the theoretical predictions $B(\pi^0 \to e^+e^-) = (6.41 \pm 0.19)\times 10^{-8}$ and $B(\eta \to \mu^+\mu^-) = (1.14 +0.06 -0.03) \times 10^{-5}$ in agreement with recent experimental data.
1910.09545
Coskun Aydin
C. Ayd{\i}n
Anapole Moment of Leptons in the Minimal Supersymmetric Standard Model
2 Figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using Feynman-'t Hooft gauge and dimensional regularization, the static parity-violating coupling of the neutrinos and charged leptons to an external electromagnetic field is calculated in the minimal supersymmetry standard model (MSSM). From the obtained result of calculations, we have seen that the main contribution come from chargino particles in MSSM.
[ { "created": "Mon, 21 Oct 2019 07:08:13 GMT", "version": "v1" }, { "created": "Wed, 8 Jan 2020 08:05:46 GMT", "version": "v2" }, { "created": "Thu, 9 Jan 2020 09:25:10 GMT", "version": "v3" }, { "created": "Fri, 29 May 2020 20:45:01 GMT", "version": "v4" } ]
2020-06-02
[ [ "Aydın", "C.", "" ] ]
Using Feynman-'t Hooft gauge and dimensional regularization, the static parity-violating coupling of the neutrinos and charged leptons to an external electromagnetic field is calculated in the minimal supersymmetry standard model (MSSM). From the obtained result of calculations, we have seen that the main contribution come from chargino particles in MSSM.
1303.0779
Ibragim Alikhanov
I. Alikhanov
CP violation in neutrino-photon scattering
10 pages, 3 figures. Version accepted for publication in J. Phys. G
J. Phys. G: 41 (2014) 025005
10.1088/0954-3899/41/2/025005
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that effects of CP violation arise in neutrino-photon scattering. Several CP-violating $\nu\gamma$ reactions are considered within the Standard Model and predictions for some observables are made. It is emphasized that neutrino-photon scattering may provide an experimental tool for testing the scale dependence of CP violation.
[ { "created": "Mon, 4 Mar 2013 18:51:27 GMT", "version": "v1" }, { "created": "Fri, 22 Mar 2013 19:24:56 GMT", "version": "v2" }, { "created": "Fri, 29 Nov 2013 06:02:47 GMT", "version": "v3" } ]
2014-01-21
[ [ "Alikhanov", "I.", "" ] ]
It is shown that effects of CP violation arise in neutrino-photon scattering. Several CP-violating $\nu\gamma$ reactions are considered within the Standard Model and predictions for some observables are made. It is emphasized that neutrino-photon scattering may provide an experimental tool for testing the scale dependence of CP violation.
2402.10471
Ning Chen
Ning Chen, Ying-nan Mao, Zhaolong Teng
The Standard Model quark/lepton masses and the Cabibbo-Kobayashi-Maskawa mixing in an ${\rm SU}(8)$ theory
37 pages with references, one appendix, 8 tables. Sequel to: arXiv:2307.07921
null
null
null
hep-ph hep-ex hep-th
http://creativecommons.org/licenses/by/4.0/
The origins of Standard Model (SM) quark/lepton masses and the Cabibbo-Kobayashi-Maskawa (CKM) mixing pattern are described in an ${\rm SU}(8)$ theory, where three-generational SM fermions transform differently. A realistic symmetry breaking pattern with three intermediate scales is described, along which all vectorlike electrically charged fermions become massive. A set of $d=5$ operators that explicitly break the emergent global symmetries are analyzed to generate the observed three-generational SM quark/lepton mass hierarchies as well as the CKM mixing pattern. All SM flavors are identified in the spectrum.
[ { "created": "Fri, 16 Feb 2024 06:31:08 GMT", "version": "v1" } ]
2024-06-17
[ [ "Chen", "Ning", "" ], [ "Mao", "Ying-nan", "" ], [ "Teng", "Zhaolong", "" ] ]
The origins of Standard Model (SM) quark/lepton masses and the Cabibbo-Kobayashi-Maskawa (CKM) mixing pattern are described in an ${\rm SU}(8)$ theory, where three-generational SM fermions transform differently. A realistic symmetry breaking pattern with three intermediate scales is described, along which all vectorlike electrically charged fermions become massive. A set of $d=5$ operators that explicitly break the emergent global symmetries are analyzed to generate the observed three-generational SM quark/lepton mass hierarchies as well as the CKM mixing pattern. All SM flavors are identified in the spectrum.
0904.1748
Peter Petreczky
Alexei Bazavov, Peter Petreczky, Alexander Velytsky
Quarkonium at Finite Temperature
50 pages, 30 figures, 2 tables; invited review for chapter in "Quark-Gluon Plasma 4
null
10.1142/9789814293297_0002
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss properties of heavy quarkonium states at high temperatures based on lattice QCD and potential models. We review recent progress made in lattice calculations of spatial static quark anti-quark correlators as well as quarkonium correlators in Euclidean time. Recent developments in effective field theory approach and potential models are also discussed.
[ { "created": "Mon, 13 Apr 2009 17:16:43 GMT", "version": "v1" } ]
2016-12-21
[ [ "Bazavov", "Alexei", "" ], [ "Petreczky", "Peter", "" ], [ "Velytsky", "Alexander", "" ] ]
We discuss properties of heavy quarkonium states at high temperatures based on lattice QCD and potential models. We review recent progress made in lattice calculations of spatial static quark anti-quark correlators as well as quarkonium correlators in Euclidean time. Recent developments in effective field theory approach and potential models are also discussed.
hep-ph/9905451
Polityko S. I.
S.I.Polityko (Irkutsk State University)
The production of light Goldstone particles on photon colliders
LaTex2e, 9 pages, 1 Postscript figure, PSfile
null
null
ISU-IAP.TH 99-02,Irkutsk
hep-ph
null
It is shown that by realizing the project of intensive $\gamma $ beams with large energy (project PLC) an essential flux of light Goldstone particles (axions, arions, familons, majorons) will be generated. The light higgs can be observed via interaction with matter. The probability of light higgs - electron production by absorption of several laser photons simultaneously is calculated.
[ { "created": "Sat, 22 May 1999 15:16:42 GMT", "version": "v1" } ]
2007-05-23
[ [ "Polityko", "S. I.", "", "Irkutsk State University" ] ]
It is shown that by realizing the project of intensive $\gamma $ beams with large energy (project PLC) an essential flux of light Goldstone particles (axions, arions, familons, majorons) will be generated. The light higgs can be observed via interaction with matter. The probability of light higgs - electron production by absorption of several laser photons simultaneously is calculated.
1704.00179
Rui-Lin Zhu
Wei Wang, Rui-Lin Zhu
Interpretation of the newly observed $\Omega_c^0$ resonances
6 pages and 2 tables; To be published in Phys.Rev.D
Phys. Rev. D 96, 014024 (2017)
10.1103/PhysRevD.96.014024
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the charmed and bottomed doubly strange baryons within the heavy-quark-light-diquark framework. The two strange quarks are assumed to lie in $S$ wave and thus their total spin is 1. We calculate the mass spectra of the $S$ and $P$ wave orbitally excited states and find the $\Omega_c^0 (2695)$ and $\Omega_c^0 (2770)$ fit well as the $S$ wave states of charmed doubly strange baryons. The five newly $\Omega_c^0(X)$ resonances observed by the LHCb Collaboration, i.e. $\Omega_c^0(3000)$, $\Omega_c^0(3050)$, $\Omega_c^0(3066)$, $\Omega_c^0(3090)$, and $\Omega_c^0(3119)$, can be interpreted as the $P$ wave orbitally excited states. In heavy quark effective theory, we analyze their decays into the $\Xi^+_c K^-$ and $\Xi_c'^+ K^-$, and point out that decays of the five P-wave $\Omega_c^0$ states into the $\Xi_c^+ K^-$ and $\Xi_c'^+K^-$ are suppressed by either heavy quark symmetry or phase space. The narrowness of the five newly observed $\Omega_c^0(X)$ states can then be naturally interpreted with heavy quark symmetry.
[ { "created": "Sat, 1 Apr 2017 15:12:20 GMT", "version": "v1" }, { "created": "Thu, 6 Jul 2017 06:17:58 GMT", "version": "v2" } ]
2017-08-02
[ [ "Wang", "Wei", "" ], [ "Zhu", "Rui-Lin", "" ] ]
We study the charmed and bottomed doubly strange baryons within the heavy-quark-light-diquark framework. The two strange quarks are assumed to lie in $S$ wave and thus their total spin is 1. We calculate the mass spectra of the $S$ and $P$ wave orbitally excited states and find the $\Omega_c^0 (2695)$ and $\Omega_c^0 (2770)$ fit well as the $S$ wave states of charmed doubly strange baryons. The five newly $\Omega_c^0(X)$ resonances observed by the LHCb Collaboration, i.e. $\Omega_c^0(3000)$, $\Omega_c^0(3050)$, $\Omega_c^0(3066)$, $\Omega_c^0(3090)$, and $\Omega_c^0(3119)$, can be interpreted as the $P$ wave orbitally excited states. In heavy quark effective theory, we analyze their decays into the $\Xi^+_c K^-$ and $\Xi_c'^+ K^-$, and point out that decays of the five P-wave $\Omega_c^0$ states into the $\Xi_c^+ K^-$ and $\Xi_c'^+K^-$ are suppressed by either heavy quark symmetry or phase space. The narrowness of the five newly observed $\Omega_c^0(X)$ states can then be naturally interpreted with heavy quark symmetry.
0912.4150
Rui Santos
Alexander Belyaev, Renato Guedes, Stefano Moretti and Rui Santos
Very Light Higgs Bosons in Extended Models at the LHC
14 pages, 11 figures
Phys.Rev.D81:095006,2010
10.1103/PhysRevD.81.095006
SHEP-09-12 and DFTT-60-2009
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Large Electron-Positron (LEP) collider experiments have constrained the mass of the Standard Model (SM) Higgs boson to be above 114.4 GeV. This bound applies to all extensions of the SM where the coupling of a Higgs boson to the Z boson and also the Higgs decay profile do not differ much from the SM one. However, in scenarios with extended Higgs sectors, this coupling can be made very small by a suitable choice of the parameters of the model. In such cases, the lightest CP-even Higgs boson mass can in turn be made very small. Such a very light Higgs state, with a mass of the order of the Z boson one or even smaller, could have escaped detection at LEP. In this work we perform a detailed parton level study on the feasibility of the detection of such a very light Higgs particle at the Large Hadron Collider (LHC) in the production process pp \to h j \to \tau^+ \tau^- j, where j is a resolved jet. We conclude that there are several models where such a Higgs state could be detected at the LHC with early data.
[ { "created": "Mon, 21 Dec 2009 16:41:20 GMT", "version": "v1" }, { "created": "Tue, 20 Apr 2010 23:19:38 GMT", "version": "v2" } ]
2010-05-25
[ [ "Belyaev", "Alexander", "" ], [ "Guedes", "Renato", "" ], [ "Moretti", "Stefano", "" ], [ "Santos", "Rui", "" ] ]
The Large Electron-Positron (LEP) collider experiments have constrained the mass of the Standard Model (SM) Higgs boson to be above 114.4 GeV. This bound applies to all extensions of the SM where the coupling of a Higgs boson to the Z boson and also the Higgs decay profile do not differ much from the SM one. However, in scenarios with extended Higgs sectors, this coupling can be made very small by a suitable choice of the parameters of the model. In such cases, the lightest CP-even Higgs boson mass can in turn be made very small. Such a very light Higgs state, with a mass of the order of the Z boson one or even smaller, could have escaped detection at LEP. In this work we perform a detailed parton level study on the feasibility of the detection of such a very light Higgs particle at the Large Hadron Collider (LHC) in the production process pp \to h j \to \tau^+ \tau^- j, where j is a resolved jet. We conclude that there are several models where such a Higgs state could be detected at the LHC with early data.
2110.15612
Shu-Sheng Xu
Shu-Sheng Xu
Pion superfluid phase transition at finite isospin chemical potential
Online published in Eur. Phys. J. A (2021) 57:298
null
10.1140/epja/s10050-021-00611-8
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The pion superfluidity phase transition at $T-\mu_I$ and $\mu_q-\mu_I$ planes are studied in the framework of Dyson-Schwinger equations. The rainbow truncation and Gaussian effective gluon propagator are employed to calculate pion condensate, $\langle\pi\rangle$, as a function of $\mu_I$ at finite $T$ and $\mu_q$. At $T=(0, 80, 113, 120)$~MeV, the $\langle\pi\rangle$ keeps zero when $\mu_I$ is less than a critical value $\mu_{Ic}(T)$. The $\langle\pi\rangle$ at $T=113$~MeV agrees with the lattice QCD result. At the $T-\mu_I$ plane, the pion superfluid phase appears at low temperature and high isospin chemical potential region. At finite $\mu_q$, $\langle\pi\rangle$ varying with $\mu_I$ almost coincide for $\mu_q<400$~MeV. At $\mu_q-\mu_I$ plane, the pion superfluid phase appears at $\mu_I\gtrsim m_\pi$ when $\mu_q<400$~MeV.
[ { "created": "Fri, 29 Oct 2021 08:26:51 GMT", "version": "v1" } ]
2021-11-01
[ [ "Xu", "Shu-Sheng", "" ] ]
The pion superfluidity phase transition at $T-\mu_I$ and $\mu_q-\mu_I$ planes are studied in the framework of Dyson-Schwinger equations. The rainbow truncation and Gaussian effective gluon propagator are employed to calculate pion condensate, $\langle\pi\rangle$, as a function of $\mu_I$ at finite $T$ and $\mu_q$. At $T=(0, 80, 113, 120)$~MeV, the $\langle\pi\rangle$ keeps zero when $\mu_I$ is less than a critical value $\mu_{Ic}(T)$. The $\langle\pi\rangle$ at $T=113$~MeV agrees with the lattice QCD result. At the $T-\mu_I$ plane, the pion superfluid phase appears at low temperature and high isospin chemical potential region. At finite $\mu_q$, $\langle\pi\rangle$ varying with $\mu_I$ almost coincide for $\mu_q<400$~MeV. At $\mu_q-\mu_I$ plane, the pion superfluid phase appears at $\mu_I\gtrsim m_\pi$ when $\mu_q<400$~MeV.
0711.1121
Sven-Olaf Moch
S. Moch and A. Mitov
Massive QCD amplitudes at higher orders
8 pages, presented at the conferences `Matter to the Deepest', Ustron (Poland), September '07, and Radcor 2007, Florence (Italy), October '07
Acta Phys.Polon.B38:3507-3516,2007; PoS RADCOR2007:027,2007
null
DESY 07-193, SFB/CPP-07-77
hep-ph
null
We consider the factorization properties of on-shell QCD amplitudes with massive partons in the limit when all kinematical invariants are large compared to the parton mass and discuss the structure of their infrared singularities. The dimensionally regulated soft poles and the large collinear logarithms of the parton masses exponentiate to all orders. Based on this factorization a simple relation between massless and massive scattering amplitudes in gauge theories can be established. We present recent applications of this relation for the calculation of the two-loop virtual QCD corrections to the hadro-production of heavy quarks.
[ { "created": "Wed, 7 Nov 2007 17:09:52 GMT", "version": "v1" } ]
2009-01-07
[ [ "Moch", "S.", "" ], [ "Mitov", "A.", "" ] ]
We consider the factorization properties of on-shell QCD amplitudes with massive partons in the limit when all kinematical invariants are large compared to the parton mass and discuss the structure of their infrared singularities. The dimensionally regulated soft poles and the large collinear logarithms of the parton masses exponentiate to all orders. Based on this factorization a simple relation between massless and massive scattering amplitudes in gauge theories can be established. We present recent applications of this relation for the calculation of the two-loop virtual QCD corrections to the hadro-production of heavy quarks.
2201.10338
Joao Pacheco B. C. de Melo Dr.
W. R. B. de Ara\'ujo (Secretaria de Educa\c{c}\~ao do Estado de S\~ao Paulo, Brazil), E. F.Suisso (Instituto Nacional de Propriedade Industrial, INPI, RJ), J. P. B. C. de Melo (Laborat\'orio de F\'isica Te\'orica e Computacional - LFTC, Universidade Cruzeiro do Sul / Universidade Cidade de S\~ao Paulo, S\~ao Paulo, Brazil), T. Frederico (Instituto Tecnol\'ogico de Aeron\'autica, DCTA, S\~ao Jo\'e dos Campos, SP, Brazil), Kazuo Tsushima (Laborat\'orio de F\'isica Te\'orica e Computacional - LFTC, Universidade Cruzeiro do Sul / Universidade Cidade de S\~ao Paulo, S\~ao Paulo, Brazil)
Nucleon Electromagnetic and Axial Form Factors in a Light-front Constituent Quark Model
Pos. style (Latex), 4 eps figures
null
null
LFTC-22-3/71
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the present work we study the effect of the scalar spin coupling of constituent quarks on the nucleon electroweak properties by introducing a valence light-front wave function with two momentum scales. By comparing the results obtained with the one scale and two scale wave function models, we have found that the last one has shown a reasonable description of the static observables and $\mu_pG_{Ep}/G_{Mp}$ ratio in which the position of the zero appears around 10~[GeV/c]$^2$ or for higher squared momentum transfers. We have also shown results for the axial-vector coupling $g_{A}$ and the nucleon axial-vector form factor. The best result for $g_A$ was obtained when the parameters of the nucleon wave function model were such that the experimental value of the neutron magnetic moment was described.
[ { "created": "Tue, 25 Jan 2022 14:23:47 GMT", "version": "v1" } ]
2022-01-26
[ [ "de Araújo", "W. R. B.", "", "Secretaria de Educação do Estado de São\n Paulo, Brazil" ], [ "Suisso", "E. F.", "", "Instituto Nacional de Propriedade Industrial,\n INPI, RJ" ], [ "de Melo", "J. P. B. C.", "", "Laboratório de Física Teórica e\n Computacion...
In the present work we study the effect of the scalar spin coupling of constituent quarks on the nucleon electroweak properties by introducing a valence light-front wave function with two momentum scales. By comparing the results obtained with the one scale and two scale wave function models, we have found that the last one has shown a reasonable description of the static observables and $\mu_pG_{Ep}/G_{Mp}$ ratio in which the position of the zero appears around 10~[GeV/c]$^2$ or for higher squared momentum transfers. We have also shown results for the axial-vector coupling $g_{A}$ and the nucleon axial-vector form factor. The best result for $g_A$ was obtained when the parameters of the nucleon wave function model were such that the experimental value of the neutron magnetic moment was described.
0804.2514
Xiaojun Bi
Xiao-Jun Bi
Big bang nucleosynthesis constrains the total annihilation cross section of neutralino dark matter
10 pages, 3 figures; discussions added
null
null
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
Assuming the lightest neutralino forms dark matter, we study its residual annihilation after freeze-out at the early universe. If taking place after the big bang nucleosynthesis (BBN) the annihilation products, especially at the hadronic modes, may cause nonthermal nuclear reaction and change the prediction of the primordial abundance of light elements in the standard BBN scenario. We therefore put constraints on the neutralino annihilation cross section. These constraints are free of the uncertainties of the dark matter profile today suffered by direct or indirect detection of dark matter. We find the constraints by BBN is important, especially when taking large $\tan\beta$. If the light element abundances can be determined with higher precision in the future the constraint will become very strong, so that a majority of the parameter space allowed by the relic density requirement may be excluded.
[ { "created": "Wed, 16 Apr 2008 07:43:45 GMT", "version": "v1" }, { "created": "Thu, 17 Apr 2008 14:02:11 GMT", "version": "v2" } ]
2008-04-17
[ [ "Bi", "Xiao-Jun", "" ] ]
Assuming the lightest neutralino forms dark matter, we study its residual annihilation after freeze-out at the early universe. If taking place after the big bang nucleosynthesis (BBN) the annihilation products, especially at the hadronic modes, may cause nonthermal nuclear reaction and change the prediction of the primordial abundance of light elements in the standard BBN scenario. We therefore put constraints on the neutralino annihilation cross section. These constraints are free of the uncertainties of the dark matter profile today suffered by direct or indirect detection of dark matter. We find the constraints by BBN is important, especially when taking large $\tan\beta$. If the light element abundances can be determined with higher precision in the future the constraint will become very strong, so that a majority of the parameter space allowed by the relic density requirement may be excluded.
hep-ph/0304076
Nobuhiro Maekawa
Nobuhiro Maekawa
Grand Unification with Anomalous U(1) Symmetry and Non-abelian Horizontal Symmetry
10 pages, Talk given at "Strong Coupling Gauge Theories and Effective Field Theories"(SCGT02) conference at Nagoya, Japan, December 10-13,2002 Reference added
null
10.1142/9789812795120_0041
KUNS-1833
hep-ph
null
Non-abelian horizontal symmetry has been considered to solve potentially SUSY flavor problem, but simple models are suffering from various problems. In this talk, we point out that (anomalous) U(1)_A gauge symmetry solves all the problems in a natural way, especially, in the E_6 grand unified theories. Combining the GUT scenario with anomalous U(1)_A gauge symmetry, in which doublet-triplet splitting and natural gauge coupling unification are realized, and realistic quark and lepton mass matrices are obtained including bi-large neutrino mixings, complete E_6* SU(3)_H (or E_6*SU(2)_H) GUTs can be obtained, in which all the three generation quarks and leptons are unified into a single multiplet (27,3) (or two multiplets (27,2+1)). This talk is based on Ref.[1].
[ { "created": "Tue, 8 Apr 2003 03:10:10 GMT", "version": "v1" }, { "created": "Tue, 15 Apr 2003 03:30:19 GMT", "version": "v2" } ]
2017-08-23
[ [ "Maekawa", "Nobuhiro", "" ] ]
Non-abelian horizontal symmetry has been considered to solve potentially SUSY flavor problem, but simple models are suffering from various problems. In this talk, we point out that (anomalous) U(1)_A gauge symmetry solves all the problems in a natural way, especially, in the E_6 grand unified theories. Combining the GUT scenario with anomalous U(1)_A gauge symmetry, in which doublet-triplet splitting and natural gauge coupling unification are realized, and realistic quark and lepton mass matrices are obtained including bi-large neutrino mixings, complete E_6* SU(3)_H (or E_6*SU(2)_H) GUTs can be obtained, in which all the three generation quarks and leptons are unified into a single multiplet (27,3) (or two multiplets (27,2+1)). This talk is based on Ref.[1].
hep-ph/9403309
Ngee-Pong Chang
Ngee Pong Chang
Chiral Morphing
14 pages, LaTeX, CCNY-HEP-94-6 Invited contribution to the Marshak Memorial volume, edited by E.C.G. Sudarshan, to be published by World Scientific Publishing Co., Singapore, 1994. **** Earlier version had email bug due to transmission problem
null
null
null
hep-ph
null
Chiral symmetry undergoes a metamorphosis at $T_c$. For $T < T_c$, the usual Noether charge, $\Qa$, is dynamically broken by the vacuum. Above $T_c$, chiral symmetry undergoes a subtle change, and the Noether charge \underline{{\em morphs}} into $\Qbeta$, with the thermal vacuum now becoming invariant under $\Qbeta$. This vacuum is however not invariant under the old $\Qa$ transformations. As a result, the pion remains strictly massless at high $T$. The pion propagates in the early universe with a halo. New order parameters are proposed to probe the structure of the new thermal vacuum.
[ { "created": "Fri, 18 Mar 1994 11:35:16 GMT", "version": "v1" }, { "created": "Mon, 28 Mar 1994 17:07:55 GMT", "version": "v2" } ]
2008-02-03
[ [ "Chang", "Ngee Pong", "" ] ]
Chiral symmetry undergoes a metamorphosis at $T_c$. For $T < T_c$, the usual Noether charge, $\Qa$, is dynamically broken by the vacuum. Above $T_c$, chiral symmetry undergoes a subtle change, and the Noether charge \underline{{\em morphs}} into $\Qbeta$, with the thermal vacuum now becoming invariant under $\Qbeta$. This vacuum is however not invariant under the old $\Qa$ transformations. As a result, the pion remains strictly massless at high $T$. The pion propagates in the early universe with a halo. New order parameters are proposed to probe the structure of the new thermal vacuum.