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2005.02320
Charles Hughes
Charles Hughes, Antonio Carlos Oliveira Da Silva, and Christine Nattrass
Model studies of fluctuations in the background for jets in heavy ion collisions
null
Phys. Rev. C 106, 2022, 044915
10.1103/PhysRevC.106.044915
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Jets produced in high energy heavy ion collisions are quenched by the quark gluon plasma. Measurements of these jets are influenced by the methods used to suppress and subtract the large, fluctuating background and the assumptions inherent in these methods. We compare the measurements of the background in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV by the ALICE Collaboration $\underline{(B. Abelev \textit{et al.}, J. High Energy Phys. \mathbf{2012}, 053)}$ to calculations in TennGen (a data-driven random background generator) and PYTHIA Angantyr. A detailed understanding of the width of these fluctuations is important for reducing uncertainties due to unfolding and extending measurements to lower momenta and larger resolution parameters. The standard deviation of the energy in random cones in TennGen is approximately in agreement with the form predicted in the ALICE paper, with deviations of 1--6%. The standard deviation of energy in random cones in Angantyr exceeds the same predictions by approximately 13%. Deviations in both models can be explained by the assumption that the single-particle $d^2N/dy$ $dp_T$ is a gamma distribution in the derivation of the prediction, whereas the model uses a different distribution. This indicates that model comparisons are potentially sensitive to the treatment of the background. We demonstrate that unfolding methods used to remove background fluctuations from jets can affect the comparisons between models and data, $\textit{even in the absence of detector effects}$. Our findings suggest the need to more carefully consider methods for comparing simulations and data.
[ { "created": "Tue, 5 May 2020 16:24:30 GMT", "version": "v1" }, { "created": "Tue, 1 Nov 2022 19:15:58 GMT", "version": "v2" } ]
2022-11-03
[ [ "Hughes", "Charles", "" ], [ "Da Silva", "Antonio Carlos Oliveira", "" ], [ "Nattrass", "Christine", "" ] ]
Jets produced in high energy heavy ion collisions are quenched by the quark gluon plasma. Measurements of these jets are influenced by the methods used to suppress and subtract the large, fluctuating background and the assumptions inherent in these methods. We compare the measurements of the background in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV by the ALICE Collaboration $\underline{(B. Abelev \textit{et al.}, J. High Energy Phys. \mathbf{2012}, 053)}$ to calculations in TennGen (a data-driven random background generator) and PYTHIA Angantyr. A detailed understanding of the width of these fluctuations is important for reducing uncertainties due to unfolding and extending measurements to lower momenta and larger resolution parameters. The standard deviation of the energy in random cones in TennGen is approximately in agreement with the form predicted in the ALICE paper, with deviations of 1--6%. The standard deviation of energy in random cones in Angantyr exceeds the same predictions by approximately 13%. Deviations in both models can be explained by the assumption that the single-particle $d^2N/dy$ $dp_T$ is a gamma distribution in the derivation of the prediction, whereas the model uses a different distribution. This indicates that model comparisons are potentially sensitive to the treatment of the background. We demonstrate that unfolding methods used to remove background fluctuations from jets can affect the comparisons between models and data, $\textit{even in the absence of detector effects}$. Our findings suggest the need to more carefully consider methods for comparing simulations and data.
1503.09063
Danny van Dyk
Thorsten Feldmann, Bastian M\"uller and Danny van Dyk (Siegen U.)
Analyzing $b\to u$ transitions in semileptonic $\bar{B}_s \to K^{*+}(\to K \pi)\ell^-\bar\nu_\ell$ decays
14 pages, 2 figures
Phys. Rev. D 92, 034013 (2015)
10.1103/PhysRevD.92.034013
SI-HEP-2015-11, QFET-2015-12, EOS-2015-01
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the semileptonic decay $\bar{B}_s \to K^{*+} \ell^-\bar\nu_\ell$, which is induced by $b\to u \ell^- \bar\nu_\ell$ transitions at the quark level. We take into account the standard model (SM) operator from $W$-boson exchange as well as possible extensions from physics beyond the SM. The secondary decay $K^{*+}\to K\pi$ can be used to study a number of angular observables, which are worked out in terms of short-distance Wilson coefficients and hadronic form factors. Our analysis allows for an independent extraction of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$ and for the determination of certain ratios of $\bar{B}_s\to K^*$ form factors. Moreover, a future precision measurement of the forward-backward asymmetry in the $\bar{B}_s \to K^{*+} \ell^-\bar\nu_\ell$ decay can be used to unambiguously verify the left-handed nature of the transition operator as predicted by the SM. We provide numerical estimates for the relevant angular observables and the resulting decay distributions on the basis of available form-factor information from lattice and sum-rule estimates. In addition, we pay particular attention to suitable combinations of angular observables in the decays $\bar{B}_s \to K^{*+}(\to K\pi)\ell^-\bar\nu_\ell$ and $\bar{B} \to K^{*0}(\to K\pi)\ell^+\ell^-$, and find that they provide complementary constraints on the relevant $b\to s$ short-distance coefficients. As a by-product, we perform a SM fit on the basis of selected experimental decay rates and hadronic input functions, which results in $|V_{ub}| = (4.07 \pm 0.20) \cdot 10^{-3}$.
[ { "created": "Tue, 31 Mar 2015 14:30:14 GMT", "version": "v1" } ]
2015-08-19
[ [ "Feldmann", "Thorsten", "", "Siegen U." ], [ "Müller", "Bastian", "", "Siegen U." ], [ "van Dyk", "Danny", "", "Siegen U." ] ]
We study the semileptonic decay $\bar{B}_s \to K^{*+} \ell^-\bar\nu_\ell$, which is induced by $b\to u \ell^- \bar\nu_\ell$ transitions at the quark level. We take into account the standard model (SM) operator from $W$-boson exchange as well as possible extensions from physics beyond the SM. The secondary decay $K^{*+}\to K\pi$ can be used to study a number of angular observables, which are worked out in terms of short-distance Wilson coefficients and hadronic form factors. Our analysis allows for an independent extraction of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$ and for the determination of certain ratios of $\bar{B}_s\to K^*$ form factors. Moreover, a future precision measurement of the forward-backward asymmetry in the $\bar{B}_s \to K^{*+} \ell^-\bar\nu_\ell$ decay can be used to unambiguously verify the left-handed nature of the transition operator as predicted by the SM. We provide numerical estimates for the relevant angular observables and the resulting decay distributions on the basis of available form-factor information from lattice and sum-rule estimates. In addition, we pay particular attention to suitable combinations of angular observables in the decays $\bar{B}_s \to K^{*+}(\to K\pi)\ell^-\bar\nu_\ell$ and $\bar{B} \to K^{*0}(\to K\pi)\ell^+\ell^-$, and find that they provide complementary constraints on the relevant $b\to s$ short-distance coefficients. As a by-product, we perform a SM fit on the basis of selected experimental decay rates and hadronic input functions, which results in $|V_{ub}| = (4.07 \pm 0.20) \cdot 10^{-3}$.
1711.05510
Tord Riemann
Johannes Bluemlein (1) and Khiem Hong Phan (1,2) and Tord Riemann (1,3) ((1) DESY, (2) Vietnam National University, (3) University of Silesia)
Scalar one-loop vertex integrals as meromorphic functions of space-time dimension d
9 pages, talk presented by TR at workshop "Matter To The Deepest", XLI International Conference on Recent Developments in Physics of Fundamental Interactions (MTTD 2017), September 3-8, 2017, Podlesice, Poland, to appear in the proceedings
null
10.5506/APhysPolB.48.2313
KW 17-002, DESY 17-186, DO-TH 17/29
hep-ph
http://creativecommons.org/licenses/by-sa/4.0/
Representations are derived for the basic scalar one-loop vertex Feynman integrals as meromorphic functions of the space-time dimension $d$ in terms of (generalized) hypergeometric functions $_2F_1$ and $F_1$. Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at $d=4+2n$, $n$ non-negative integers, may be derived from the representations easily. The Feynman integrals studied here may be used as building blocks for the calculation of one-loop and higher-loop scalar and tensor amplitudes. From the recursion relation presented, higher n-point functions may be obtained in a straightforward manner.
[ { "created": "Wed, 15 Nov 2017 11:50:55 GMT", "version": "v1" } ]
2018-05-09
[ [ "Bluemlein", "Johannes", "", "DESY" ], [ "Phan", "Khiem Hong", "", "DESY", "Vietnam National University" ], [ "Riemann", "Tord", "", "DESY", "University of Silesia" ] ]
Representations are derived for the basic scalar one-loop vertex Feynman integrals as meromorphic functions of the space-time dimension $d$ in terms of (generalized) hypergeometric functions $_2F_1$ and $F_1$. Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at $d=4+2n$, $n$ non-negative integers, may be derived from the representations easily. The Feynman integrals studied here may be used as building blocks for the calculation of one-loop and higher-loop scalar and tensor amplitudes. From the recursion relation presented, higher n-point functions may be obtained in a straightforward manner.
hep-ph/9410259
null
Anjan S. Joshipura and Jose W. F. Valle
Reconciling Cold Dark Matter with COBE/IRAS Plus Solar and Atmospheric Neutrino Data
latex. This version includes the figure as a compressed fig.uu file, appended at the end. Moreover it adds a reference to the work of Chun, Kim and Kim
Nucl.Phys.B440:647-660,1995
10.1016/0550-3213(95)00060-6
null
hep-ph astro-ph
null
We present a model where an unstable MeV Majorana tau \neu can naturally reconcile the cold dark matter model (CDM) with cosmological observations of large and small scale density fluctuations and, simultaneously, with data on solar and atmospheric neutrinos. The solar \neu deficit is explained through long wavelength, so-called {\sl just-so} oscillations involving conversions of \ne into both \nm and a sterile species \ns, while atmospheric \neu data are explained through \nm to \ne conversions. Future long baseline \neu oscillation experiments, as well as some reactor experiments will test this hypothesis. The model is based on the spontaneous violation of a global lepton number symmetry at the weak scale. This symmetry plays a key role in generating the cosmologically required decay of the \nt with lifetime $\tau_{\nu_\tau} \sim 10^2 - 10^4$ seconds, as well as the masses and oscillations of the three light \neus \ne, \nm and \ns required in order to account for solar and atmospheric \neu data. It also leads to the invisibly decaying higgs signature that can be searched at LEP and future particle colliders.
[ { "created": "Tue, 11 Oct 1994 12:02:29 GMT", "version": "v1" }, { "created": "Wed, 26 Oct 1994 14:22:06 GMT", "version": "v2" } ]
2009-09-25
[ [ "Joshipura", "Anjan S.", "" ], [ "Valle", "Jose W. F.", "" ] ]
We present a model where an unstable MeV Majorana tau \neu can naturally reconcile the cold dark matter model (CDM) with cosmological observations of large and small scale density fluctuations and, simultaneously, with data on solar and atmospheric neutrinos. The solar \neu deficit is explained through long wavelength, so-called {\sl just-so} oscillations involving conversions of \ne into both \nm and a sterile species \ns, while atmospheric \neu data are explained through \nm to \ne conversions. Future long baseline \neu oscillation experiments, as well as some reactor experiments will test this hypothesis. The model is based on the spontaneous violation of a global lepton number symmetry at the weak scale. This symmetry plays a key role in generating the cosmologically required decay of the \nt with lifetime $\tau_{\nu_\tau} \sim 10^2 - 10^4$ seconds, as well as the masses and oscillations of the three light \neus \ne, \nm and \ns required in order to account for solar and atmospheric \neu data. It also leads to the invisibly decaying higgs signature that can be searched at LEP and future particle colliders.
hep-ph/9704283
null
F. Benatti and R. Floreanini
Experimental limits on complete positivity from the K-K system
13 pages, plain-TeX, to appear in Phys. Lett. B
Phys.Lett. B401 (1997) 337-346
10.1016/S0370-2693(97)00409-7
null
hep-ph hep-th
null
Available data on measured observables allow deriving estimates for some of the phenomenological parameters that characterize the time-evolution and decay of the neutral kaon system based on the hypothesis of complete positivity. The present experimental uncertainties are still too large to permit a full test of complete positivity.
[ { "created": "Thu, 10 Apr 1997 14:14:22 GMT", "version": "v1" } ]
2009-10-30
[ [ "Benatti", "F.", "" ], [ "Floreanini", "R.", "" ] ]
Available data on measured observables allow deriving estimates for some of the phenomenological parameters that characterize the time-evolution and decay of the neutral kaon system based on the hypothesis of complete positivity. The present experimental uncertainties are still too large to permit a full test of complete positivity.
hep-ph/0011386
Dominique Monderen
Dominique Monderen
Neutrino focusing
7 pages; 2 figures. Talk presented at the 'XXXVth Rencontres de Moriond ElectroWeak Interactions and Unified Theories', March 2000, Les Arcs, France
null
null
ULB-TH00/20
hep-ph astro-ph
null
We study the lensing of neutrinos by astrophysical objects. At the difference of photons, neutrinos can cross a stellar core; as a result the lens quality improves. While Uranians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.
[ { "created": "Thu, 30 Nov 2000 11:04:40 GMT", "version": "v1" } ]
2007-05-23
[ [ "Monderen", "Dominique", "" ] ]
We study the lensing of neutrinos by astrophysical objects. At the difference of photons, neutrinos can cross a stellar core; as a result the lens quality improves. While Uranians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.
1601.04928
Radja Boughezal
Radja Boughezal
NNLO phenomenology using N-jettiness subtraction
8 pages, 5 figures, to appear in the proceedings of the 12th International Symposium on Radiative Corrections (Radcor 2015) and LoopFest XIV (Radiative Corrections for the LHC and Future Colliders). V2: added references
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss next-to-next-to-leading order QCD results for Higgs, W-boson and Z-boson production in association with a jet in hadronic collisions, obtained using the recently developed N-jettiness subtraction method.
[ { "created": "Tue, 19 Jan 2016 14:14:53 GMT", "version": "v1" }, { "created": "Thu, 21 Jan 2016 13:07:01 GMT", "version": "v2" } ]
2016-01-22
[ [ "Boughezal", "Radja", "" ] ]
We discuss next-to-next-to-leading order QCD results for Higgs, W-boson and Z-boson production in association with a jet in hadronic collisions, obtained using the recently developed N-jettiness subtraction method.
hep-ph/9910312
Kent Hornbostel
K. Hornbostel
String Breaking in Two-Dimensional QCD
9 pages, 3 figures, LaTeX2e Contribution to the Proceedings of the TJNAF Workshop on the Transition from Low to High Q Form Factors, Athens, GA, September 17, 1999. Minor typos corrected
null
null
SMUHEP 99-11
hep-ph hep-lat
null
I present results of a numerical calculation of the effects of light quark-antiquark pairs on the linear heavy-quark potential in light-cone quantized two-dimensional QCD. I extract the potential from the Q-Qbar component of the ground-state wavefunction, and observe string breaking at the heavy-light meson pair threshold. I briefly comment on the states responsible for the breaking.
[ { "created": "Tue, 12 Oct 1999 17:31:45 GMT", "version": "v1" }, { "created": "Tue, 2 Nov 1999 01:24:04 GMT", "version": "v2" } ]
2007-05-23
[ [ "Hornbostel", "K.", "" ] ]
I present results of a numerical calculation of the effects of light quark-antiquark pairs on the linear heavy-quark potential in light-cone quantized two-dimensional QCD. I extract the potential from the Q-Qbar component of the ground-state wavefunction, and observe string breaking at the heavy-light meson pair threshold. I briefly comment on the states responsible for the breaking.
hep-ph/9811226
Xiao-Gang He
Wu-Sheng Dai (Nankai) Xiao-Gang He (NTU), Xue-Qian Li (Nankai) and Gang Zhao (Nankai)
Non-Spectator Contributions to Inclusive Charmless $B$ Decays
11 pages, Revtex
Phys. Rev. D 60, 034005 (1999)
10.1103/PhysRevD.60.034005
null
hep-ph
null
The light quarks inside $B$ mesons are usually treated as spectators and do not affect the decay rates which are assumed to be purely due to b quark decays. In this paper we calculate the non-spectator contributions to inclusive charmless $B$ decays due to the spectator effects. We find that the non-spectator contributions to the branching ratio for $\bar B^0$ are small ($<2\times 10^{-4}$), but the contributions to $\Delta S = 0$ and $\Delta S = -1$, $B^-$ decay branching ratios can be as large as $-7.5\times 10^{-4}$ and $2\times 10^{-3}$, respectively. These contributions may play an important role in rare charmless $B$ decays.
[ { "created": "Tue, 3 Nov 1998 06:49:27 GMT", "version": "v1" } ]
2016-08-25
[ [ "Dai", "Wu-Sheng", "", "Nankai" ], [ "He", "Xiao-Gang", "", "NTU" ], [ "Li", "Xue-Qian", "", "Nankai" ], [ "Zhao", "Gang", "", "Nankai" ] ]
The light quarks inside $B$ mesons are usually treated as spectators and do not affect the decay rates which are assumed to be purely due to b quark decays. In this paper we calculate the non-spectator contributions to inclusive charmless $B$ decays due to the spectator effects. We find that the non-spectator contributions to the branching ratio for $\bar B^0$ are small ($<2\times 10^{-4}$), but the contributions to $\Delta S = 0$ and $\Delta S = -1$, $B^-$ decay branching ratios can be as large as $-7.5\times 10^{-4}$ and $2\times 10^{-3}$, respectively. These contributions may play an important role in rare charmless $B$ decays.
1706.01964
William Klemm
Abdesslam Arhrib, Rachid Benbrik, Rikard Enberg, William Klemm, Stefano Moretti and Shoaib Munir
Identifying a light charged Higgs boson at the LHC Run II
11 pages, 7 figures
Phys.Lett. B774 (2017) 591-598
10.1016/j.physletb.2017.10.006
KIAS-P17035
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyse the phenomenological implications of a light Higgs boson, $h$, within the CP-conserving 2-Higgs Doublet Model (2HDM) Type-I, for the detection prospects of the charged $H^\pm$ state at Run II of the Large Hadron Collider (LHC), assuming $\sqrt{s}=13$ TeV as energy and ${\cal O}(100~{\rm fb}^{-1})$ as luminosity. When sufficiently light, this $h$ state can open up the bosonic decay channel $H^\pm \to W^{\pm(*)}h$, which may have a branching ratio significantly exceeding those of the $H^\pm \to \tau\nu$ and $H^\pm \to cs$ channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, $H$, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which $m_{H^\pm} < m_t +m_b$ that are still consistent with the most recent limits from experimental searches. We find in these regions that, when the $H^\pm \to W^{\pm(*)}h$ decay mode is the dominant one, the $h$ can be highly fermiophobic, with a considerably large decay rate in the $\gamma\gamma$ channel. This can result in the total cross section of the $\sigma(pp\to H^\pm h \to W^{\pm(*)} + 4\gamma)$ process reaching up to ${\cal O}(100~{\rm fb})$. We therefore investigate the possibility of observing this spectacular signal at the LHC Run II.
[ { "created": "Tue, 6 Jun 2017 20:34:35 GMT", "version": "v1" } ]
2018-09-14
[ [ "Arhrib", "Abdesslam", "" ], [ "Benbrik", "Rachid", "" ], [ "Enberg", "Rikard", "" ], [ "Klemm", "William", "" ], [ "Moretti", "Stefano", "" ], [ "Munir", "Shoaib", "" ] ]
We analyse the phenomenological implications of a light Higgs boson, $h$, within the CP-conserving 2-Higgs Doublet Model (2HDM) Type-I, for the detection prospects of the charged $H^\pm$ state at Run II of the Large Hadron Collider (LHC), assuming $\sqrt{s}=13$ TeV as energy and ${\cal O}(100~{\rm fb}^{-1})$ as luminosity. When sufficiently light, this $h$ state can open up the bosonic decay channel $H^\pm \to W^{\pm(*)}h$, which may have a branching ratio significantly exceeding those of the $H^\pm \to \tau\nu$ and $H^\pm \to cs$ channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, $H$, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which $m_{H^\pm} < m_t +m_b$ that are still consistent with the most recent limits from experimental searches. We find in these regions that, when the $H^\pm \to W^{\pm(*)}h$ decay mode is the dominant one, the $h$ can be highly fermiophobic, with a considerably large decay rate in the $\gamma\gamma$ channel. This can result in the total cross section of the $\sigma(pp\to H^\pm h \to W^{\pm(*)} + 4\gamma)$ process reaching up to ${\cal O}(100~{\rm fb})$. We therefore investigate the possibility of observing this spectacular signal at the LHC Run II.
2003.12850
Igor Volobuev
Eduard Boos, Igor Volobuev
The specificity of the interactions of electroweak gauge bosons coming from extra dimensions
null
null
10.1142/S0217751X21500500
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the specificity of the interactions of the electroweak gauge boson excitations in models with warped extra dimensions. In particular, we show that the couplings of the gauge boson excitations $W^{\prime}$, $Z^{\prime}$, and $\gamma^\prime$ to the SM gauge bosons treated as the zero modes of the 5D gauge fields are either exactly equal to zero or very much suppressed. In the former case, the three-particle and four-particle interaction Lagrangians of the SM gauge bosons and their lowest excitations are found explicitly. Meanwhile, the couplings of $W^{\prime}$, $Z^{\prime}$, and $\gamma^\prime$ to the SM fermions are non-zero allowing for their production and decays. These are the characteristic features of the gauge boson excitations in models with warped extra dimensions, which distinguish them from the gauge boson excitations in other models beyond the SM.
[ { "created": "Sat, 28 Mar 2020 17:50:10 GMT", "version": "v1" }, { "created": "Mon, 1 Jun 2020 17:45:31 GMT", "version": "v2" }, { "created": "Thu, 10 Dec 2020 16:14:30 GMT", "version": "v3" } ]
2021-04-21
[ [ "Boos", "Eduard", "" ], [ "Volobuev", "Igor", "" ] ]
We discuss the specificity of the interactions of the electroweak gauge boson excitations in models with warped extra dimensions. In particular, we show that the couplings of the gauge boson excitations $W^{\prime}$, $Z^{\prime}$, and $\gamma^\prime$ to the SM gauge bosons treated as the zero modes of the 5D gauge fields are either exactly equal to zero or very much suppressed. In the former case, the three-particle and four-particle interaction Lagrangians of the SM gauge bosons and their lowest excitations are found explicitly. Meanwhile, the couplings of $W^{\prime}$, $Z^{\prime}$, and $\gamma^\prime$ to the SM fermions are non-zero allowing for their production and decays. These are the characteristic features of the gauge boson excitations in models with warped extra dimensions, which distinguish them from the gauge boson excitations in other models beyond the SM.
hep-ph/9906348
Zhang. dh
De-Hai Zhang (Graduate School, Academia Sinica)
The Cosmological Constant as a Residual Energy in the Chaotic Inflationary Model
7 pages, no figures, Latex
null
null
GS-AS-990612
hep-ph astro-ph gr-qc
null
A new idea of the cosmological constant is proposed in this paper. Due to the horizon is limited, the quantum fluctuation of the inflaton field is not zero, a nonzero vacuum energy is remained as a residual inflationary energy of an unusual potential, however the true stable vacuum energy is zero fortunately. A unified model of the cosmological constant and the chaotic inflation is proposed, which satisfies almost all cosmological phenomenology and will can be tested by data of the cosmic large scale structure.
[ { "created": "Sat, 12 Jun 1999 15:58:56 GMT", "version": "v1" } ]
2007-05-23
[ [ "Zhang", "De-Hai", "", "Graduate School, Academia Sinica" ] ]
A new idea of the cosmological constant is proposed in this paper. Due to the horizon is limited, the quantum fluctuation of the inflaton field is not zero, a nonzero vacuum energy is remained as a residual inflationary energy of an unusual potential, however the true stable vacuum energy is zero fortunately. A unified model of the cosmological constant and the chaotic inflation is proposed, which satisfies almost all cosmological phenomenology and will can be tested by data of the cosmic large scale structure.
2304.08575
June-Young Kim
June-Young Kim, Ho-Yeon Won, Jose L. Goity, Christian Weiss
QCD angular momentum in $N \rightarrow \Delta$ transitions
7 pages, 1 figure
null
10.1016/j.physletb.2023.138083
JLAB-THY-23-3795
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
$N \rightarrow \Delta$ transitions offer new possibilities for exploring the isovector component of the QCD quark angular momentum (AM) operator causing the $J^{u - d}$ flavor asymmetry in the nucleon. We extend the concept of QCD AM to transitions between baryon states, using light-front densities of the energy-momentum tensor in transversely localized states. We calculate the $N \rightarrow \Delta$ transition AM in the $1/N_c$ expansion, connect it with the $J^{u - d}$ flavor asymmetry in the nucleon, and estimate the values using lattice QCD results. In the same setup we connect the transition AM to the transition GPDs sampled in hard exclusive electroproduction processes with $N \rightarrow \Delta$ transitions, enabling experimental study of the transition AM.
[ { "created": "Mon, 17 Apr 2023 19:33:56 GMT", "version": "v1" } ]
2023-08-09
[ [ "Kim", "June-Young", "" ], [ "Won", "Ho-Yeon", "" ], [ "Goity", "Jose L.", "" ], [ "Weiss", "Christian", "" ] ]
$N \rightarrow \Delta$ transitions offer new possibilities for exploring the isovector component of the QCD quark angular momentum (AM) operator causing the $J^{u - d}$ flavor asymmetry in the nucleon. We extend the concept of QCD AM to transitions between baryon states, using light-front densities of the energy-momentum tensor in transversely localized states. We calculate the $N \rightarrow \Delta$ transition AM in the $1/N_c$ expansion, connect it with the $J^{u - d}$ flavor asymmetry in the nucleon, and estimate the values using lattice QCD results. In the same setup we connect the transition AM to the transition GPDs sampled in hard exclusive electroproduction processes with $N \rightarrow \Delta$ transitions, enabling experimental study of the transition AM.
hep-ph/9411326
null
Thomas G. Rizzo
Constraints on the Left-Right Symmetric Model from $b\to s\gamma$
6 pages, 8 figures(available on request), LaTex, Worldsci Macro
null
null
SLAC-PUB-6719
hep-ph
null
The recent observation by the CLEO Collaboration of the inclusive decay $b\to s\gamma$ with a branching fraction consistent with the expectations of the Standard Model is used to constrain the parameter space of the Left-Right Symmetric Model. Two scenarios are considered: ($i$) equal left- and right- handed Cabibbo-Kobayashi-Maskawa mixing matrices, $V_L=V_R (~{\rm or}~V_R^*)$ and ($ii$) the Gronau-Wakaizumi model wherein B-decays proceed only via right-handed currents and $V_L$ and $V_R$ are quite distinct. In the later case the bounds from $b\to s\gamma$ are combined with other constraints leaving a parameter range that is very highly restricted and which implies that this model may soon be completely ruled out by improving data. (To appear in the {\it Proceedings of the 1994 International Workshop on B Physics, Physics Beyond the Standard Model at the B Factory}, Nagoya, Japan, October 26-28, 1994.)
[ { "created": "Thu, 17 Nov 1994 22:38:34 GMT", "version": "v1" } ]
2009-09-25
[ [ "Rizzo", "Thomas G.", "" ] ]
The recent observation by the CLEO Collaboration of the inclusive decay $b\to s\gamma$ with a branching fraction consistent with the expectations of the Standard Model is used to constrain the parameter space of the Left-Right Symmetric Model. Two scenarios are considered: ($i$) equal left- and right- handed Cabibbo-Kobayashi-Maskawa mixing matrices, $V_L=V_R (~{\rm or}~V_R^*)$ and ($ii$) the Gronau-Wakaizumi model wherein B-decays proceed only via right-handed currents and $V_L$ and $V_R$ are quite distinct. In the later case the bounds from $b\to s\gamma$ are combined with other constraints leaving a parameter range that is very highly restricted and which implies that this model may soon be completely ruled out by improving data. (To appear in the {\it Proceedings of the 1994 International Workshop on B Physics, Physics Beyond the Standard Model at the B Factory}, Nagoya, Japan, October 26-28, 1994.)
1604.07633
Alexei P. Martynenko
A.A. Karyasov, A.P. Martynenko, F.A. Martynenko (Samara University)
Relativistic corrections to the pair $B_c$-meson production in $e^+e^-$ annihilation
15 pages, 2 figures. arXiv admin note: text overlap with arXiv:1308.3998
Nuclear Physics B 911 (2016) 36-51
10.1016/j.nuclphysb.2016.07.034
SSU-HEP-16/04
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Relativistic corrections to the pair $B_c$-meson production in $e^+e^-$-annihilation are calculated. We investigate a production of pair pseudoscalar, vector and pseudoscalar+vector $B_c$-mesons in the leading order perturbative quantum chromodynamics and relativistic quark model. Relativistic expressions of the pair production cross sections are obtained. Their numerical evaluation shows that relativistic effects in the production amplitudes and bound state wave functions three times reduce nonrelativistic results at the center-of-mass energy s=22 GeV.
[ { "created": "Tue, 26 Apr 2016 11:52:07 GMT", "version": "v1" } ]
2016-08-11
[ [ "Karyasov", "A. A.", "", "Samara University" ], [ "Martynenko", "A. P.", "", "Samara University" ], [ "Martynenko", "F. A.", "", "Samara University" ] ]
Relativistic corrections to the pair $B_c$-meson production in $e^+e^-$-annihilation are calculated. We investigate a production of pair pseudoscalar, vector and pseudoscalar+vector $B_c$-mesons in the leading order perturbative quantum chromodynamics and relativistic quark model. Relativistic expressions of the pair production cross sections are obtained. Their numerical evaluation shows that relativistic effects in the production amplitudes and bound state wave functions three times reduce nonrelativistic results at the center-of-mass energy s=22 GeV.
2204.12231
Akanksha Bhardwaj
Oliver Atkinson, Akanksha Bhardwaj, Christoph Englert, Partha Konar, Vishal S. Ngairangbam, and Michael Spannowsky
IRC-safe Graph Autoencoder for unsupervised anomaly detection
16 pages, 5 figures, Matched with the published version
Front. Artif. Intell., 22 July 2022 Sec. Big Data and AI in High Energy Physics
10.3389/frai.2022.943135
null
hep-ph cs.LG hep-ex
http://creativecommons.org/licenses/by/4.0/
Anomaly detection through employing machine learning techniques has emerged as a novel powerful tool in the search for new physics beyond the Standard Model. Historically similar to the development of jet observables, theoretical consistency has not always assumed a central role in the fast development of algorithms and neural network architectures. In this work, we construct an infrared and collinear safe autoencoder based on graph neural networks by employing energy-weighted message passing. We demonstrate that whilst this approach has theoretically favourable properties, it also exhibits formidable sensitivity to non-QCD structures.
[ { "created": "Tue, 26 Apr 2022 11:21:09 GMT", "version": "v1" }, { "created": "Sun, 31 Jul 2022 22:36:48 GMT", "version": "v2" } ]
2022-08-02
[ [ "Atkinson", "Oliver", "" ], [ "Bhardwaj", "Akanksha", "" ], [ "Englert", "Christoph", "" ], [ "Konar", "Partha", "" ], [ "Ngairangbam", "Vishal S.", "" ], [ "Spannowsky", "Michael", "" ] ]
Anomaly detection through employing machine learning techniques has emerged as a novel powerful tool in the search for new physics beyond the Standard Model. Historically similar to the development of jet observables, theoretical consistency has not always assumed a central role in the fast development of algorithms and neural network architectures. In this work, we construct an infrared and collinear safe autoencoder based on graph neural networks by employing energy-weighted message passing. We demonstrate that whilst this approach has theoretically favourable properties, it also exhibits formidable sensitivity to non-QCD structures.
1404.0272
Basudeb Dasgupta
Basudeb Dasgupta, and Alexei Yu. Smirnov
Leptonic CP Violation Phases, Quark-Lepton Similarity and Seesaw Mechanism
30 pages. v3(typos fixed, matches version published in Nucl. Phys. B)
Nuclear Physics B, Volume 884, July 2014, Pages 357-378
10.1016/j.nuclphysb.2014.05.001
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore generic features of the leptonic CP violation in the framework of the seesaw type I mechanism with similarity of the Dirac lepton and quarks mass matrices $m_D$. For this, we elaborate on the standard parametrization conditions which allow to simultaneously obtain the Dirac and Majorana phases. If the only origin of CP violation is the left-handed (LH) transformation which diagonalizes $m_D$ (similar to quarks), the leptonic CP violation is suppressed and the Dirac phase is close to $\pi$ or to $0$ with $\sin \delta_{CP} \approx (\sin \theta_{13}^q /\sin \theta_{13}) \cos \theta_{23} \sin \delta_q \sim \lambda^2 \sin \delta_q$. Here $\lambda \sim \theta_C$, is the Cabibbo mixing angle, and $\theta_{13}^q$ and $\theta_{13}$ are the 1-3 mixing angles of quarks and leptons respectively. The Majorana phases $\beta_1$ and $\beta_2$ are suppressed as $\lambda^3\sin\delta_q$. For Majorana neutrinos implied by seesaw, the right-handed (RH) transformations are important. We explore the simplest extension inspired by Left-Right (L-R) symmetry with small CKM-type CP violation. In this case, seesaw enhancement of the CP violation occurs due to strong hierarchy of the eigenvalues of $m_D$ leading to $\delta_{CP} \sim 1$. The enhancement is absent under the phase factorization conditions which require certain relations between parameters of the Majorana mass matrix of RH neutrinos.
[ { "created": "Tue, 1 Apr 2014 15:19:59 GMT", "version": "v1" }, { "created": "Mon, 7 Apr 2014 12:37:13 GMT", "version": "v2" }, { "created": "Tue, 20 May 2014 11:47:07 GMT", "version": "v3" } ]
2014-05-30
[ [ "Dasgupta", "Basudeb", "" ], [ "Smirnov", "Alexei Yu.", "" ] ]
We explore generic features of the leptonic CP violation in the framework of the seesaw type I mechanism with similarity of the Dirac lepton and quarks mass matrices $m_D$. For this, we elaborate on the standard parametrization conditions which allow to simultaneously obtain the Dirac and Majorana phases. If the only origin of CP violation is the left-handed (LH) transformation which diagonalizes $m_D$ (similar to quarks), the leptonic CP violation is suppressed and the Dirac phase is close to $\pi$ or to $0$ with $\sin \delta_{CP} \approx (\sin \theta_{13}^q /\sin \theta_{13}) \cos \theta_{23} \sin \delta_q \sim \lambda^2 \sin \delta_q$. Here $\lambda \sim \theta_C$, is the Cabibbo mixing angle, and $\theta_{13}^q$ and $\theta_{13}$ are the 1-3 mixing angles of quarks and leptons respectively. The Majorana phases $\beta_1$ and $\beta_2$ are suppressed as $\lambda^3\sin\delta_q$. For Majorana neutrinos implied by seesaw, the right-handed (RH) transformations are important. We explore the simplest extension inspired by Left-Right (L-R) symmetry with small CKM-type CP violation. In this case, seesaw enhancement of the CP violation occurs due to strong hierarchy of the eigenvalues of $m_D$ leading to $\delta_{CP} \sim 1$. The enhancement is absent under the phase factorization conditions which require certain relations between parameters of the Majorana mass matrix of RH neutrinos.
hep-ph/9511386
Steve Kuhlmann
J. Huston, E. Kovacs, S. Kuhlmann, H. L. Lai, J. F. Owens, D. Soper, W. K. Tung
Large Transverse Momentum Jet Production and the Gluon Distribution Inside the Proton
6 page Latex file using epsf.sty for 4 ps figures. Revised with more up-to-date gluon distributions
Phys.Rev.Lett. 77 (1996) 444-447
10.1103/PhysRevLett.77.444
Michigan State Report # MSU-HEP-50812, FSU-HEP-951031, CTEQ-512
hep-ph hep-ex
null
The CDF experiment has reported an excess of high-$p_t$ jets compared to previous next-to-leading order QCD expectations. Before attributing this to new physics effects, we investigate whether these high-$p_t$ jets can be explained by a modified gluon distribution inside the proton. We find enough flexibility in a global QCD analysis including the CDF inclusive jet data to provide a 25-35\% increase in the jet cross sections at the highest $p_t$ of the experiment. Two possible sets of parton distributions are presented, and the effects of these on other existing data sets are presented. Further theoretical and experimental work needed to clarify unresolved issues is outlined.
[ { "created": "Tue, 21 Nov 1995 19:57:26 GMT", "version": "v1" }, { "created": "Mon, 13 May 1996 22:16:41 GMT", "version": "v2" } ]
2009-10-28
[ [ "Huston", "J.", "" ], [ "Kovacs", "E.", "" ], [ "Kuhlmann", "S.", "" ], [ "Lai", "H. L.", "" ], [ "Owens", "J. F.", "" ], [ "Soper", "D.", "" ], [ "Tung", "W. K.", "" ] ]
The CDF experiment has reported an excess of high-$p_t$ jets compared to previous next-to-leading order QCD expectations. Before attributing this to new physics effects, we investigate whether these high-$p_t$ jets can be explained by a modified gluon distribution inside the proton. We find enough flexibility in a global QCD analysis including the CDF inclusive jet data to provide a 25-35\% increase in the jet cross sections at the highest $p_t$ of the experiment. Two possible sets of parton distributions are presented, and the effects of these on other existing data sets are presented. Further theoretical and experimental work needed to clarify unresolved issues is outlined.
1311.1052
Dalibor Kekez
D. Klabu\v{c}ar, S. Beni\'c, D. Horvati\'c, D. Kekez
eta' multiplicity and Witten-Veneziano relation at T>0
appolb.sty, 6 pages, no figures. arXiv admin note: substantial text overlap with arXiv:1105.0356
Acta Phys.Polon.Supp. 6 (2013) 3, 935
10.5506/APhysPolBSupp.6.935
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent RHIC results on eta' multiplicity in heavy-ion collisions are of great importance because they clearly signal a partial restoration of U_A(1) symmetry at high temperatures T, and thus provide an unambiguous signature of the formation of a new state of matter. Prompted by these experimental results of STAR and PHENIX collaborations, we discuss and propose the minimal generalization of the Witten-Veneziano relation to finite T.
[ { "created": "Tue, 5 Nov 2013 13:57:01 GMT", "version": "v1" } ]
2013-11-06
[ [ "Klabučar", "D.", "" ], [ "Benić", "S.", "" ], [ "Horvatić", "D.", "" ], [ "Kekez", "D.", "" ] ]
Recent RHIC results on eta' multiplicity in heavy-ion collisions are of great importance because they clearly signal a partial restoration of U_A(1) symmetry at high temperatures T, and thus provide an unambiguous signature of the formation of a new state of matter. Prompted by these experimental results of STAR and PHENIX collaborations, we discuss and propose the minimal generalization of the Witten-Veneziano relation to finite T.
0801.4235
Mihail Chizhov
M. V. Chizhov, V. A. Bednyakov and J. A. Budagov
Proposal for chiral bosons search at LHC via their unique new signature
4 pages, 5 figures
Phys.Atom.Nucl.71:2096-2100,2008
10.1134/S1063778808120107
null
hep-ph hep-ex
null
The resonance production of new chiral spin-1 bosons and their detection through the Drell--Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross-sections of the chiral bosons production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit--Wigner resonance peak in the invariant dilepton mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse momentum distribution. Second, the lepton angular distribution in the Collins-Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar "swallowtail" shape.
[ { "created": "Mon, 28 Jan 2008 10:40:51 GMT", "version": "v1" } ]
2009-01-26
[ [ "Chizhov", "M. V.", "" ], [ "Bednyakov", "V. A.", "" ], [ "Budagov", "J. A.", "" ] ]
The resonance production of new chiral spin-1 bosons and their detection through the Drell--Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross-sections of the chiral bosons production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit--Wigner resonance peak in the invariant dilepton mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse momentum distribution. Second, the lepton angular distribution in the Collins-Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar "swallowtail" shape.
2204.13121
Kimiko Yamashita
Xu Li, Ken Mimasu, Kimiko Yamashita, Chengjie Yang, Cen Zhang, Shuang-Yong Zhou
Moments for positivity: using Drell-Yan data to test positivity bounds and reverse-engineer new physics
54 pages, 8 figures, 9 tables, version to appear in JHEP
JHEP10(2022)107
10.1007/JHEP10(2022)107
USTC-ICTS/PCFT-22-12, KCL-PH-TH/2022-09
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Moments of the leptonic angular distribution in the Drell-Yan process have recently been shown to be sensitive probes of a specific class of dimension-8, four-fermion operators in the Standard Model Effective Field Theory, involving a pair of quarks and leptons. The same operators are also subject to positivity bounds, when requiring the associated (unknown) UV completion to obey basic principles of quantum field theory. We perform a phenomenological study to quantify the sensitivity of the high-luminosity LHC to this set of operators and, by extension, the positivity bounds. We further extend the angular basis of moments and consider double differential information to improve the ability to disentangle the different operators, leading to a sensitivity to new physics scales up to 3 TeV. We use this information to explore the violation of positivity at the LHC as a way to test the underlying principles of quantum field theory. Finally, we present a case study which combines our results with information from other (current and prospective) experiments, as well as the positivity cone to infer the properties of possible tree-level UV completions. The data lead to robust, model-independent lower bounds on the $M/\sqrt{g}$ combination of the particle mass and coupling, for states that couple to right-handed leptons and/or up quarks.
[ { "created": "Wed, 27 Apr 2022 18:00:01 GMT", "version": "v1" }, { "created": "Sat, 15 Oct 2022 01:31:43 GMT", "version": "v2" } ]
2022-10-19
[ [ "Li", "Xu", "" ], [ "Mimasu", "Ken", "" ], [ "Yamashita", "Kimiko", "" ], [ "Yang", "Chengjie", "" ], [ "Zhang", "Cen", "" ], [ "Zhou", "Shuang-Yong", "" ] ]
Moments of the leptonic angular distribution in the Drell-Yan process have recently been shown to be sensitive probes of a specific class of dimension-8, four-fermion operators in the Standard Model Effective Field Theory, involving a pair of quarks and leptons. The same operators are also subject to positivity bounds, when requiring the associated (unknown) UV completion to obey basic principles of quantum field theory. We perform a phenomenological study to quantify the sensitivity of the high-luminosity LHC to this set of operators and, by extension, the positivity bounds. We further extend the angular basis of moments and consider double differential information to improve the ability to disentangle the different operators, leading to a sensitivity to new physics scales up to 3 TeV. We use this information to explore the violation of positivity at the LHC as a way to test the underlying principles of quantum field theory. Finally, we present a case study which combines our results with information from other (current and prospective) experiments, as well as the positivity cone to infer the properties of possible tree-level UV completions. The data lead to robust, model-independent lower bounds on the $M/\sqrt{g}$ combination of the particle mass and coupling, for states that couple to right-handed leptons and/or up quarks.
2406.05180
Miha Nemevsek
Pietro Baratella, Miha Nemev\v{s}ek, Yutaro Shoji, Katarina Trailovi\'c, Lorenzo Ubaldi
The Standard Model lifetime is slightly shorter
5 pages + Supplemental, 2 figures
null
null
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
We revisit the decay rate of the electroweak vacuum in the Standard Model with the full one-loop prefactor. We focus on the gauge degrees of freedom and derive the degeneracy factors appearing in the functional determinant using group theoretical arguments. Our treatment shows that the transverse modes were previously overcounted, so we revise the calculation of that part of the prefactor. The new result modifies the gauge fields' contribution by $7\%$ and slightly decreases the previously predicted lifetime of the electroweak vacuum, which remains much longer than the age of the universe. Our discussion of the transverse mode degeneracy applies to any calculation of functional determinants involving gauge fields in four dimensions.
[ { "created": "Fri, 7 Jun 2024 18:00:01 GMT", "version": "v1" } ]
2024-06-11
[ [ "Baratella", "Pietro", "" ], [ "Nemevšek", "Miha", "" ], [ "Shoji", "Yutaro", "" ], [ "Trailović", "Katarina", "" ], [ "Ubaldi", "Lorenzo", "" ] ]
We revisit the decay rate of the electroweak vacuum in the Standard Model with the full one-loop prefactor. We focus on the gauge degrees of freedom and derive the degeneracy factors appearing in the functional determinant using group theoretical arguments. Our treatment shows that the transverse modes were previously overcounted, so we revise the calculation of that part of the prefactor. The new result modifies the gauge fields' contribution by $7\%$ and slightly decreases the previously predicted lifetime of the electroweak vacuum, which remains much longer than the age of the universe. Our discussion of the transverse mode degeneracy applies to any calculation of functional determinants involving gauge fields in four dimensions.
hep-ph/9610491
Nicos Stefanis
N. G. Stefanis, A. I. Karanikas, and C. N. Ktorides
Worldline description of the Isgur-Wise function
LaTeX, using Worldstyle and comprising three eps files (5 pages in total). Invited talk presented by the first author at the International Workshop Quark Confinement and the Hadron Spectrum II, June 26-29, 1996, Villa Olmo, Como, Italy. To appear in the Proceedings (World Scientific)
null
null
RUB-TPII-11-96 (July 1996)
hep-ph
null
An effective field theoretic description of the Isgur-Wise function in heavy-meson transitions is presented which emulates soft interactions by a fermion worldline with an infinitesimal self-intersecting loop. A point-splitting regularization technique is used, which replaces pointlike worldlines by ``ribbons'' in the sense of Witten. The calculated vertex function is correctly normalized, does not depend on the heavy-quark mass, and complies with different sets of recent experimental data of the ARGUS and CLEO collaborations.
[ { "created": "Fri, 25 Oct 1996 14:57:15 GMT", "version": "v1" } ]
2007-05-23
[ [ "Stefanis", "N. G.", "" ], [ "Karanikas", "A. I.", "" ], [ "Ktorides", "C. N.", "" ] ]
An effective field theoretic description of the Isgur-Wise function in heavy-meson transitions is presented which emulates soft interactions by a fermion worldline with an infinitesimal self-intersecting loop. A point-splitting regularization technique is used, which replaces pointlike worldlines by ``ribbons'' in the sense of Witten. The calculated vertex function is correctly normalized, does not depend on the heavy-quark mass, and complies with different sets of recent experimental data of the ARGUS and CLEO collaborations.
hep-ph/9801356
A. A. Penin
J.H.K\"uhn, A.A.Penin and A.A.Pivovarov
Coulomb resummation for $b \bar b$ system near threshold and precision determination of $\al_s$ and $m_b$.
22 pages Latex, some misprints in the Appendix are corrected
Nucl.Phys.B534:356-370,1998
10.1016/S0550-3213(98)00607-5
preprint TTP98-01
hep-ph
null
We analyze sum rules for the $\Upsilon$ system with resummation of threshold effects on the basis of the nonrelativistic Coulomb approximation. We find for the pole mass of the bottom quark $m_b=4.75\pm 0.04 GeV$ and for the strong coupling constant $\al_s(M_Z)=0.118\pm 0.006$. The origin of the contradiction between two recent estimates obtained within the same formal framework is clarified.
[ { "created": "Tue, 20 Jan 1998 11:06:55 GMT", "version": "v1" }, { "created": "Sun, 22 Feb 1998 14:57:54 GMT", "version": "v2" }, { "created": "Fri, 27 Feb 1998 09:10:43 GMT", "version": "v3" }, { "created": "Sun, 5 Apr 1998 12:51:35 GMT", "version": "v4" } ]
2016-08-15
[ [ "Kühn", "J. H.", "" ], [ "Penin", "A. A.", "" ], [ "Pivovarov", "A. A.", "" ] ]
We analyze sum rules for the $\Upsilon$ system with resummation of threshold effects on the basis of the nonrelativistic Coulomb approximation. We find for the pole mass of the bottom quark $m_b=4.75\pm 0.04 GeV$ and for the strong coupling constant $\al_s(M_Z)=0.118\pm 0.006$. The origin of the contradiction between two recent estimates obtained within the same formal framework is clarified.
0706.2168
Mu-Chun Chen
Mu-Chun Chen
Models of Neutrino Masses and Mixing
Talk presented at the 2nd International Colliders to Cosmic Rays Conference (C2CR07), Lake Tahoe, CA, February 25 - March 1, 2007; 8 pages; 2 figures
AIPConf.Proc.928:153-160,2007
10.1063/1.2775909
UCI-TR-2007-27, FERMILAB-CONF-07-200-T
hep-ph
null
Neutrino physics has entered an era of precision measurements. With these precise measurements, we may be able to distinguish different models that have been constructed to explain the small neutrino masses and the large mixing among them. In this talk, I review some of the existing theoretical models and their predictions for neutrino oscillations.
[ { "created": "Thu, 14 Jun 2007 17:45:40 GMT", "version": "v1" } ]
2008-11-26
[ [ "Chen", "Mu-Chun", "" ] ]
Neutrino physics has entered an era of precision measurements. With these precise measurements, we may be able to distinguish different models that have been constructed to explain the small neutrino masses and the large mixing among them. In this talk, I review some of the existing theoretical models and their predictions for neutrino oscillations.
1205.0521
Ulrich Jentschura
U. D. Jentschura and B. J. Wundt
From Generalized Dirac Equations to a Candidate for Dark Energy
26 pages; RevTeX; 1 figure; some typographical errors corrected in Sec. 5C; Version 6: typographical error in Eq.(3.3b) corrected; reference [39] updated; ISRN High Energy Physics, in press
ISRN High Energy Physics 2013 (2013) 374612
10.1155/2013/374612
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider extensions of the Dirac equation with mass terms m1+i*gamma5*m2 and i*m_1+gamma*m2. The corresponding Hamiltonians are Hermitian and pseudo-Hermitian ("gamma5 Hermitian"), respectively. The fundamental spinor solutions for all generalized Dirac equations are found in the helicity basis and brought into concise analytic form. We postulate that the time-ordered product of field operators should yield the Feynman propagator (i*epsilon prescription), and we also postulate that the tardyonic as well as tachyonic Dirac equations should have a smooth massless limit. These postulates lead to sum rules that connect the form of the fundamental field anticommutators with the tensor sums of the fundamental plane-wave eigenspinors and the projectors over positive-energy and negative-energy states. In the massless case, the sum rules are fulfilled by two egregiously simple, distinguished functional forms. The first sum rule remains valid in the case of a tardyonic theory and leads to the canonical massive Dirac field. The second sum rule is valid for a tachyonic mass term and leads to a natural suppression of the right-handed helicity states for tachyonic particles, and left-handed helicity states for tachyonic spin-1/2 antiparticles. When applied to neutrinos, the theory contains a free tachyonic mass parameter. Tachyons are known to be repulsed by gravity. We discuss a possible role of a tachyonic neutrino as a contribution to the accelerated expansion of the Universe ("dark energy").
[ { "created": "Wed, 2 May 2012 18:49:00 GMT", "version": "v1" }, { "created": "Tue, 19 Jun 2012 21:25:31 GMT", "version": "v2" }, { "created": "Mon, 27 Aug 2012 14:47:18 GMT", "version": "v3" }, { "created": "Wed, 3 Oct 2012 10:42:02 GMT", "version": "v4" }, { "created": "Fri, 16 Nov 2012 16:02:11 GMT", "version": "v5" }, { "created": "Wed, 12 Dec 2012 19:09:40 GMT", "version": "v6" } ]
2013-03-11
[ [ "Jentschura", "U. D.", "" ], [ "Wundt", "B. J.", "" ] ]
We consider extensions of the Dirac equation with mass terms m1+i*gamma5*m2 and i*m_1+gamma*m2. The corresponding Hamiltonians are Hermitian and pseudo-Hermitian ("gamma5 Hermitian"), respectively. The fundamental spinor solutions for all generalized Dirac equations are found in the helicity basis and brought into concise analytic form. We postulate that the time-ordered product of field operators should yield the Feynman propagator (i*epsilon prescription), and we also postulate that the tardyonic as well as tachyonic Dirac equations should have a smooth massless limit. These postulates lead to sum rules that connect the form of the fundamental field anticommutators with the tensor sums of the fundamental plane-wave eigenspinors and the projectors over positive-energy and negative-energy states. In the massless case, the sum rules are fulfilled by two egregiously simple, distinguished functional forms. The first sum rule remains valid in the case of a tardyonic theory and leads to the canonical massive Dirac field. The second sum rule is valid for a tachyonic mass term and leads to a natural suppression of the right-handed helicity states for tachyonic particles, and left-handed helicity states for tachyonic spin-1/2 antiparticles. When applied to neutrinos, the theory contains a free tachyonic mass parameter. Tachyons are known to be repulsed by gravity. We discuss a possible role of a tachyonic neutrino as a contribution to the accelerated expansion of the Universe ("dark energy").
hep-ph/9912441
Catherine Eguren
Fabian Zomer
Inclusive Deep Inelastic Scattering at HERA and related phenomenology
14 pages
null
null
LAL 99-69
hep-ph
null
Recent measurements of inclusive deep inelastic scattering differential cross-section in the range 1.5 \gev2\le Q^2\le 30000 \gev2 and 5\cdot 10^{-6}\le x\le 0.65 are presented. Phenomenological analyses performed from these measurements are also described.
[ { "created": "Tue, 21 Dec 1999 12:50:07 GMT", "version": "v1" }, { "created": "Tue, 4 Jan 2000 10:08:52 GMT", "version": "v2" } ]
2007-05-23
[ [ "Zomer", "Fabian", "" ] ]
Recent measurements of inclusive deep inelastic scattering differential cross-section in the range 1.5 \gev2\le Q^2\le 30000 \gev2 and 5\cdot 10^{-6}\le x\le 0.65 are presented. Phenomenological analyses performed from these measurements are also described.
1506.05799
Ahmed Ismail
M. Cahill-Rowley, J.L. Hewett, A. Ismail, and T.G. Rizzo
The ATLAS Z + MET Excess in the MSSM
20 pages, 11 figures
Phys. Rev. D 92, 075029 (2015)
10.1103/PhysRevD.92.075029
SLAC-PUB-16308
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We demonstrate that the $3\sigma$ excess observed by ATLAS in the Z + MET channel can be explained within the context of the MSSM. Using the freedom inherent in the pMSSM, we perform a detailed analysis of the parameter space and find a scenario that describes the excess while simultaneously complying with all other search constraints from the Run I data at 7 and 8 TeV, including the Z + MET analysis by CMS. We generate a small sample of simplified models, using promising models from our existing pMSSM sample as seeds, and study their properties. The successful region is described by the production of 1st/2nd generation squark pairs, followed by their decay into a bino-like neutralino which in turn decays into a Higgsino-like LSP triplet by emitting a Z boson, i.e., $\tilde q\to\tilde B\to\tilde h$ with $\tilde q = \tilde Q_L,\tilde u_R,$ or $\tilde d_R$. The sweet spot for the sparticle spectrum is found to have squark masses in the 500-750 GeV range, with bino masses near 350 GeV with a mass splitting of 150-200 GeV with the Higgsino LSP. If this excess holds, then this scenario predicts that a signal will be observed in the 0l + jets and/or 1l + jets searches in the early operations of Run II.
[ { "created": "Thu, 18 Jun 2015 20:00:24 GMT", "version": "v1" } ]
2015-10-28
[ [ "Cahill-Rowley", "M.", "" ], [ "Hewett", "J. L.", "" ], [ "Ismail", "A.", "" ], [ "Rizzo", "T. G.", "" ] ]
We demonstrate that the $3\sigma$ excess observed by ATLAS in the Z + MET channel can be explained within the context of the MSSM. Using the freedom inherent in the pMSSM, we perform a detailed analysis of the parameter space and find a scenario that describes the excess while simultaneously complying with all other search constraints from the Run I data at 7 and 8 TeV, including the Z + MET analysis by CMS. We generate a small sample of simplified models, using promising models from our existing pMSSM sample as seeds, and study their properties. The successful region is described by the production of 1st/2nd generation squark pairs, followed by their decay into a bino-like neutralino which in turn decays into a Higgsino-like LSP triplet by emitting a Z boson, i.e., $\tilde q\to\tilde B\to\tilde h$ with $\tilde q = \tilde Q_L,\tilde u_R,$ or $\tilde d_R$. The sweet spot for the sparticle spectrum is found to have squark masses in the 500-750 GeV range, with bino masses near 350 GeV with a mass splitting of 150-200 GeV with the Higgsino LSP. If this excess holds, then this scenario predicts that a signal will be observed in the 0l + jets and/or 1l + jets searches in the early operations of Run II.
hep-ph/9706230
Lisi Eligio
G.L. Fogli, E. Lisi, D. Montanino, G. Scioscia (Bari U. & INFN, Bari)
Reconciling solar and terrestrial neutrino oscillation evidences with minimum sacrifice
16 pages (RevTeX) + 3 figures (postscript); requires epsfig.sty
Phys.Rev.D56:4365-4373,1997
10.1103/PhysRevD.56.4365
BARI-TH/273-97
hep-ph
null
The present possible evidences in favor of neutrino masses and mixings from solar, atmospheric, and accelerator experiments cannot be all reconciled in a three-family framework, unless some data are excluded. We grade all possible three-family scenarios according to their compatibility with the available data. A recently proposed scenario appears to emerge naturally as the most likely solution to all oscillation evidences, with the only exception of the angular dependence of multi-GeV atmospheric data in the Kamiokande experiment. We describe in detail the status and the phenomenological implications of this ``minimum sacrifice'' solution.
[ { "created": "Tue, 3 Jun 1997 14:24:32 GMT", "version": "v1" } ]
2009-10-07
[ [ "Fogli", "G. L.", "", "Bari U. & INFN, Bari" ], [ "Lisi", "E.", "", "Bari U. & INFN, Bari" ], [ "Montanino", "D.", "", "Bari U. & INFN, Bari" ], [ "Scioscia", "G.", "", "Bari U. & INFN, Bari" ] ]
The present possible evidences in favor of neutrino masses and mixings from solar, atmospheric, and accelerator experiments cannot be all reconciled in a three-family framework, unless some data are excluded. We grade all possible three-family scenarios according to their compatibility with the available data. A recently proposed scenario appears to emerge naturally as the most likely solution to all oscillation evidences, with the only exception of the angular dependence of multi-GeV atmospheric data in the Kamiokande experiment. We describe in detail the status and the phenomenological implications of this ``minimum sacrifice'' solution.
hep-ph/9611323
Mikhail Krivoruchenko
M. I. Krivoruchenko (ITEP)
Explicit Solutions to the Unitarity Relations for Isovector Nucleon Form Factors
Talk given at the 6-th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, Blaubeuren/Tuebingen, 10-14 July, 1995; published in PiN Newsletter, 10 (1995) 156
PiN Newslett.10:156-158,1995
null
null
hep-ph
null
The explicit one-dimensional integral representations for isovector nucleon form factors are constructed by solving the unitarity relations in terms of the pion form factor and imaginary parts of the t-channel p-wave $\pi N$-scattering amplitudes. The possibility of computation of the high-energy parts of the integrals with the use of the information on the low-energy real parts of the $\pi N$-scattering amplitudes is discussed.
[ { "created": "Thu, 14 Nov 1996 10:44:50 GMT", "version": "v1" } ]
2011-04-15
[ [ "Krivoruchenko", "M. I.", "", "ITEP" ] ]
The explicit one-dimensional integral representations for isovector nucleon form factors are constructed by solving the unitarity relations in terms of the pion form factor and imaginary parts of the t-channel p-wave $\pi N$-scattering amplitudes. The possibility of computation of the high-energy parts of the integrals with the use of the information on the low-energy real parts of the $\pi N$-scattering amplitudes is discussed.
2101.02225
Varun Vaidya
Varun Vaidya
Forward scattering in a thermal Plasma
31 pages
null
null
MIT--CTP 5268
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I examine the regime of forward scattering of an energetic particle in a Plasma medium in thermal equilibrium. Treating the particle as an open quantum system interacting with a bath, I look at the time evolution of the reduced density matrix of the system. The kinematic and dynamical time scales that emerge can exist in several possible hierarchies which can lead to different EFT formulations. I show that in certain hierarchies, it becomes necessary to account for arbitrary number of coherent exchanges between the system and the bath going beyond the independent scattering paradigm. Analytic results are obtained in certain limits and the formalism is applied for the measurement of transverse momentum broadening of a quark in a Quark Gluon Plasma medium.
[ { "created": "Wed, 6 Jan 2021 19:00:34 GMT", "version": "v1" } ]
2021-01-08
[ [ "Vaidya", "Varun", "" ] ]
I examine the regime of forward scattering of an energetic particle in a Plasma medium in thermal equilibrium. Treating the particle as an open quantum system interacting with a bath, I look at the time evolution of the reduced density matrix of the system. The kinematic and dynamical time scales that emerge can exist in several possible hierarchies which can lead to different EFT formulations. I show that in certain hierarchies, it becomes necessary to account for arbitrary number of coherent exchanges between the system and the bath going beyond the independent scattering paradigm. Analytic results are obtained in certain limits and the formalism is applied for the measurement of transverse momentum broadening of a quark in a Quark Gluon Plasma medium.
hep-ph/0611209
Gary Steigman
Gary Steigman
BBN And The CBR Probe The Early Universe
8 pages, 4 figures; to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 2006"
AIPConf.Proc.903:40-47,2007
10.1063/1.2735129
null
hep-ph astro-ph nucl-th
null
Big Bang Nucleosynthesis (BBN) and the Cosmic Background Radiation (CBR) provide complementary probes of the early evolution of the Universe and of its particle content. Neutrinos play important roles in both cases, influencing the primordial abundances of the nuclides produced by BBN during the first 20 minutes, as well as the spectrum of temperature fluctuations imprinted on the CBR when the Universe is some 400 thousand years old. The physical effects relevant at these widely separated epochs are reviewed and the theoretical predictions are compared with observational data to explore the consistency of the standard models of cosmology and particle physics and to constrain beyond-the-standard-model physics and cosmology.
[ { "created": "Wed, 15 Nov 2006 19:34:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Steigman", "Gary", "" ] ]
Big Bang Nucleosynthesis (BBN) and the Cosmic Background Radiation (CBR) provide complementary probes of the early evolution of the Universe and of its particle content. Neutrinos play important roles in both cases, influencing the primordial abundances of the nuclides produced by BBN during the first 20 minutes, as well as the spectrum of temperature fluctuations imprinted on the CBR when the Universe is some 400 thousand years old. The physical effects relevant at these widely separated epochs are reviewed and the theoretical predictions are compared with observational data to explore the consistency of the standard models of cosmology and particle physics and to constrain beyond-the-standard-model physics and cosmology.
1510.00965
Nejc Ko\v{s}nik
Svjetlana Fajfer, Nejc Ko\v{s}nik
Prospects of discovering new physics in rare charm decays
13 pages, 3 figures, typos fixed
null
10.1140/epjc/s10052-015-3801-2
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The LHCb bounds on the branching ratio of rare decay $D^0 \to \mu^+ \mu^-$ and the constraints on the branching ratio of $D^+ \to \pi^+ \mu^+ \mu^-$ in the nonresonant regions enable us to improve constraints on new physics contributions. Using the effective Lagrangian approach we determine sizes of the Wilson coefficients allowed by the existing LHCb bounds on rare charm decays. Then we discuss contributions to rare charm meson decay observables in several models of new physics: a model with an additional spin-1 weak triplet, leptoquark models, Two Higgs doublets model of type III, and a $Z'$ model. Here we complement the discussion by $D^0 - \bar D^0$ oscillations data. Among considered models, only leptoquarks can significantly modify Wilson coefficients. Assuming that the differential decay width for $D^+ \to \pi^+ \mu^+ \mu^-$ receives NP contribution, while the differential decay width for $D^+ \to \pi^+ e^+ e^-$ is Standard Model-like, we find that lepton flavor universality can be violated and might be observed at high dilepton invariant mass.
[ { "created": "Sun, 4 Oct 2015 18:36:30 GMT", "version": "v1" }, { "created": "Wed, 28 Oct 2015 10:41:09 GMT", "version": "v2" }, { "created": "Fri, 21 May 2021 13:00:32 GMT", "version": "v3" } ]
2021-05-24
[ [ "Fajfer", "Svjetlana", "" ], [ "Košnik", "Nejc", "" ] ]
The LHCb bounds on the branching ratio of rare decay $D^0 \to \mu^+ \mu^-$ and the constraints on the branching ratio of $D^+ \to \pi^+ \mu^+ \mu^-$ in the nonresonant regions enable us to improve constraints on new physics contributions. Using the effective Lagrangian approach we determine sizes of the Wilson coefficients allowed by the existing LHCb bounds on rare charm decays. Then we discuss contributions to rare charm meson decay observables in several models of new physics: a model with an additional spin-1 weak triplet, leptoquark models, Two Higgs doublets model of type III, and a $Z'$ model. Here we complement the discussion by $D^0 - \bar D^0$ oscillations data. Among considered models, only leptoquarks can significantly modify Wilson coefficients. Assuming that the differential decay width for $D^+ \to \pi^+ \mu^+ \mu^-$ receives NP contribution, while the differential decay width for $D^+ \to \pi^+ e^+ e^-$ is Standard Model-like, we find that lepton flavor universality can be violated and might be observed at high dilepton invariant mass.
1508.00912
Stephen P. Martin
Stephen P. Martin
Four-loop Standard Model effective potential at leading order in QCD
15 pages
Phys. Rev. D 92, 054029 (2015)
10.1103/PhysRevD.92.054029
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The leading QCD part of the four-loop contribution to the effective potential for the Standard Model Higgs field is found. As a byproduct, I also find the corresponding contribution to the four-loop beta function of the Higgs self-interaction coupling.
[ { "created": "Tue, 4 Aug 2015 20:24:55 GMT", "version": "v1" } ]
2015-09-30
[ [ "Martin", "Stephen P.", "" ] ]
The leading QCD part of the four-loop contribution to the effective potential for the Standard Model Higgs field is found. As a byproduct, I also find the corresponding contribution to the four-loop beta function of the Higgs self-interaction coupling.
2211.14341
Martin Beneke
Martin Beneke, Stefan Lederer, Clara Peset
Electroweak resummation of neutralino dark-matter annihilation into high-energy photons
31 pages, 3 figures
null
10.1007/JHEP01(2023)171
TUM-HEP-1426/22
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the resummation of large electroweak Sudakov logarithms for the annihilation of neutralino DM with $\mathcal{O}$(TeV) mass to high-energy photons in the minimal supersymmetric standard model, extending previous work on the minimal wino and Higgsino models. We find that NLL resummation reduces the yield of photons by about $20\%$ for Higgsino-dominated DM at masses around 1~TeV, and up to $45\%$ for neutralinos with larger wino admixture at heavier masses near 3~TeV. This sizable effect is relevant when observations or exclusion limits are translated into MSSM parameter-space constraints.
[ { "created": "Fri, 25 Nov 2022 19:00:58 GMT", "version": "v1" } ]
2023-02-22
[ [ "Beneke", "Martin", "" ], [ "Lederer", "Stefan", "" ], [ "Peset", "Clara", "" ] ]
We consider the resummation of large electroweak Sudakov logarithms for the annihilation of neutralino DM with $\mathcal{O}$(TeV) mass to high-energy photons in the minimal supersymmetric standard model, extending previous work on the minimal wino and Higgsino models. We find that NLL resummation reduces the yield of photons by about $20\%$ for Higgsino-dominated DM at masses around 1~TeV, and up to $45\%$ for neutralinos with larger wino admixture at heavier masses near 3~TeV. This sizable effect is relevant when observations or exclusion limits are translated into MSSM parameter-space constraints.
1203.2387
Robert Foot
R. Foot
Mirror dark matter interpretations of the DAMA, CoGeNT and CRESST-II data
20 pages, minor changes, a minor mistake fixed
null
10.1103/PhysRevD.86.023524
null
hep-ph astro-ph.GA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The CRESST-II collaboration have announced evidence for the direct detection of dark matter in 730 kg-days exposure of a CaWO$_4$ target. We examine these new results, along with DAMA and CoGeNT data, in the context of the mirror dark matter framework. We show that all three experiments can be simultaneously explained via kinetic mixing induced elastic scattering of a mirror metal component off target nuclei. This metal component can be as heavy as Fe$'$ if the galactic rotational velocity is relatively low: $v_{rot} \stackrel{<}{\sim} 220$ km/s. This explanation is consistent with the constraints from the other experiments, such as CDMS/Ge, CDMS/Si and XENON100 when modest $\sim 20-30%$ uncertainties in energy scale are considered.
[ { "created": "Mon, 12 Mar 2012 00:26:24 GMT", "version": "v1" }, { "created": "Mon, 19 Mar 2012 02:47:09 GMT", "version": "v2" }, { "created": "Sat, 18 May 2013 04:41:42 GMT", "version": "v3" } ]
2015-06-04
[ [ "Foot", "R.", "" ] ]
The CRESST-II collaboration have announced evidence for the direct detection of dark matter in 730 kg-days exposure of a CaWO$_4$ target. We examine these new results, along with DAMA and CoGeNT data, in the context of the mirror dark matter framework. We show that all three experiments can be simultaneously explained via kinetic mixing induced elastic scattering of a mirror metal component off target nuclei. This metal component can be as heavy as Fe$'$ if the galactic rotational velocity is relatively low: $v_{rot} \stackrel{<}{\sim} 220$ km/s. This explanation is consistent with the constraints from the other experiments, such as CDMS/Ge, CDMS/Si and XENON100 when modest $\sim 20-30%$ uncertainties in energy scale are considered.
hep-ph/0407313
Vladimir Pascalutsa
Vladimir Pascalutsa (JLab & W&M College), Barry R. Holstein (JLab & UMass), Marc Vanderhaeghen (JLab & W&M College)
A Derivative of the Gerasimov-Drell-Hearn Sum Rule
11 pages, 5 figures, minor corrections, published version
Phys.Lett.B600:239-247,2004
10.1016/j.physletb.2004.09.006
WM-04-111, JLAB-THY-04-250
hep-ph hep-th nucl-th
null
We derive a sum rule which establishes a linear relation between a particle's anomalous magnetic moment and a quantity connected to the photoabsorption cross-section. This quantity cannot be measured directly. However, it can be computed within a given theory. As an example, we demonstrate validity of the sum rule in QED at tree level--the renowned Schwinger's correction to the anomalous magnetic moment is readily reproduced. In the case of the strong interactions, we also consider the calculation of the nucleon magnetic moment within chiral theories.
[ { "created": "Tue, 27 Jul 2004 21:03:05 GMT", "version": "v1" }, { "created": "Thu, 2 Sep 2004 16:05:37 GMT", "version": "v2" }, { "created": "Sat, 11 Sep 2004 00:39:58 GMT", "version": "v3" } ]
2014-11-17
[ [ "Pascalutsa", "Vladimir", "", "JLab & W&M College" ], [ "Holstein", "Barry R.", "", "JLab &\n UMass" ], [ "Vanderhaeghen", "Marc", "", "JLab & W&M College" ] ]
We derive a sum rule which establishes a linear relation between a particle's anomalous magnetic moment and a quantity connected to the photoabsorption cross-section. This quantity cannot be measured directly. However, it can be computed within a given theory. As an example, we demonstrate validity of the sum rule in QED at tree level--the renowned Schwinger's correction to the anomalous magnetic moment is readily reproduced. In the case of the strong interactions, we also consider the calculation of the nucleon magnetic moment within chiral theories.
0801.3349
Wei Zhu
Jianhong Ruan, Zhenqi Shen and Wei Zhu
Nuclear Shadowing and Antishadowing in a Unitarized BFKL Equation
19 pages, 6 figures, to be appeared in Chinese Physics C
null
10.1088/1674-1137/32/9/009
null
hep-ph
null
The nuclear shadowing and antishadowing effects are explained by a unitarized BFKL equation. The $Q^2$- and $x$-variations of the nuclear parton distributions are detailed based on the level of the unintegrated gluon distribution. In particular, the asymptotical behavior of the unintegrated gluon distribution near the saturation limit in nuclear targets is studied. Our results in the nuclear targets are insensitive to the input distributions if the parameters are fixed by the data of a free proton.
[ { "created": "Tue, 22 Jan 2008 11:46:57 GMT", "version": "v1" } ]
2015-05-13
[ [ "Ruan", "Jianhong", "" ], [ "Shen", "Zhenqi", "" ], [ "Zhu", "Wei", "" ] ]
The nuclear shadowing and antishadowing effects are explained by a unitarized BFKL equation. The $Q^2$- and $x$-variations of the nuclear parton distributions are detailed based on the level of the unintegrated gluon distribution. In particular, the asymptotical behavior of the unintegrated gluon distribution near the saturation limit in nuclear targets is studied. Our results in the nuclear targets are insensitive to the input distributions if the parameters are fixed by the data of a free proton.
1610.06299
Agustin Moyotl-Acuahuitl Mr.
A. Moyotl, S. Chamorro-Solano, H. Castilla-Valdez and M. A. P\'erez
New physics effects in the Higgs trilinear self-coupling through one-loop radiative corrections
15 pages, 9 figures, 1 table, Revised version, we include appendices with further technical details on our renormalization scheme, some references added and minor typos corrected
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compute the one-loop corrections to the triple Higgs self-interaction $hhh$ in the framework of the Standard Model (SM), the Two Higgs Doublet Model type III (THDM-III) and the Littlest Higgs Model with T parity (LHBM+T). Our results are compared with previous results for the SM. In particular, we find that an imaginary part for the $\lambda_{hhh}$ form factor is induced when one of the Higgs boson legs is off-mass shell with 4-momentum magnitude higher than the Higgs boson mass. This contribution is sensitive to virtual effects of the Higgs self-interaction, that induces a radiative correction to the $hhh$ coupling of order 11%. However, the radiative corrections associated to the new degrees of freedom of the THDM-III and the LHBM+T are rather smaller and comparable to the $W^\pm$ and $Z^0$ gauge bosons one-loop corrections.
[ { "created": "Thu, 20 Oct 2016 06:26:43 GMT", "version": "v1" }, { "created": "Mon, 31 Oct 2016 06:51:21 GMT", "version": "v2" }, { "created": "Mon, 27 Nov 2017 23:08:22 GMT", "version": "v3" } ]
2017-11-29
[ [ "Moyotl", "A.", "" ], [ "Chamorro-Solano", "S.", "" ], [ "Castilla-Valdez", "H.", "" ], [ "Pérez", "M. A.", "" ] ]
We compute the one-loop corrections to the triple Higgs self-interaction $hhh$ in the framework of the Standard Model (SM), the Two Higgs Doublet Model type III (THDM-III) and the Littlest Higgs Model with T parity (LHBM+T). Our results are compared with previous results for the SM. In particular, we find that an imaginary part for the $\lambda_{hhh}$ form factor is induced when one of the Higgs boson legs is off-mass shell with 4-momentum magnitude higher than the Higgs boson mass. This contribution is sensitive to virtual effects of the Higgs self-interaction, that induces a radiative correction to the $hhh$ coupling of order 11%. However, the radiative corrections associated to the new degrees of freedom of the THDM-III and the LHBM+T are rather smaller and comparable to the $W^\pm$ and $Z^0$ gauge bosons one-loop corrections.
2305.13061
Thomas Blackburn
T. G. Blackburn, B. King, S. Tang
Simulations of laser-driven strong-field QED with Ptarmigan: Resolving wavelength-scale interference and $\gamma$-ray polarization
19 pages, 6 figures; additional discussion of validity and updated figures; to appear in Physics of Plasmas
Phys. Plasmas 30, 093903 (2023)
10.1063/5.0159963
null
hep-ph physics.plasm-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Accurate modelling is necessary to support precision experiments investigating strong-field QED phenomena. This modelling is particularly challenging in the transition between the perturbative and nonperturbative regimes, where the normalized laser amplitude $a_0$ is comparable to unity and wavelength-scale interference is significant. Here we describe how to simulate nonlinear Compton scattering, Breit-Wheeler pair creation, and trident pair creation in this regime, using the Monte Carlo particle-tracking code Ptarmigan. This code simulates collisions between high-intensity lasers and beams of electrons or $\gamma$ rays, primarily in the framework of the locally monochromatic approximation (LMA). We benchmark our simulation results against full QED calculations for pulsed plane waves and show that they are accurate at the level of a few per cent, across the full range of particle energies and laser intensities. This work extends our previous results to linearly polarized lasers and arbitrarily polarized $\gamma$ rays.
[ { "created": "Mon, 22 May 2023 14:20:41 GMT", "version": "v1" }, { "created": "Tue, 5 Sep 2023 11:23:20 GMT", "version": "v2" } ]
2023-09-21
[ [ "Blackburn", "T. G.", "" ], [ "King", "B.", "" ], [ "Tang", "S.", "" ] ]
Accurate modelling is necessary to support precision experiments investigating strong-field QED phenomena. This modelling is particularly challenging in the transition between the perturbative and nonperturbative regimes, where the normalized laser amplitude $a_0$ is comparable to unity and wavelength-scale interference is significant. Here we describe how to simulate nonlinear Compton scattering, Breit-Wheeler pair creation, and trident pair creation in this regime, using the Monte Carlo particle-tracking code Ptarmigan. This code simulates collisions between high-intensity lasers and beams of electrons or $\gamma$ rays, primarily in the framework of the locally monochromatic approximation (LMA). We benchmark our simulation results against full QED calculations for pulsed plane waves and show that they are accurate at the level of a few per cent, across the full range of particle energies and laser intensities. This work extends our previous results to linearly polarized lasers and arbitrarily polarized $\gamma$ rays.
2107.02225
Meijian Li
Meijian Li, Tuomas Lappi, Xingbo Zhao
Scattering and gluon emission in a color field: a light-front Hamiltonian approach
null
Phys. Rev. D104, 056014 (2021)
10.1103/PhysRevD.104.056014
null
hep-ph nucl-th
http://creativecommons.org/licenses/by-nc-nd/4.0/
We develop a numerical method to nonperturbatively study scattering and gluon emission of a quark from a colored target using a light-front Hamiltonian approach. The target is described as a classical color field, as in the Color Glass Condensate effective theory. The Fock space of the scattering system is restricted to the $\ket{q}+\ket{qg}$ sectors, but the time evolution of this truncated system is solved exactly. This method allows us to study the interplay between coherence and multiple scattering in gluon emission. It could be applied both to studying subeikonal effects in high energy scattering and to understanding jet quenching in a hot plasma.
[ { "created": "Mon, 5 Jul 2021 18:48:43 GMT", "version": "v1" }, { "created": "Sat, 13 Nov 2021 10:45:20 GMT", "version": "v2" } ]
2021-11-16
[ [ "Li", "Meijian", "" ], [ "Lappi", "Tuomas", "" ], [ "Zhao", "Xingbo", "" ] ]
We develop a numerical method to nonperturbatively study scattering and gluon emission of a quark from a colored target using a light-front Hamiltonian approach. The target is described as a classical color field, as in the Color Glass Condensate effective theory. The Fock space of the scattering system is restricted to the $\ket{q}+\ket{qg}$ sectors, but the time evolution of this truncated system is solved exactly. This method allows us to study the interplay between coherence and multiple scattering in gluon emission. It could be applied both to studying subeikonal effects in high energy scattering and to understanding jet quenching in a hot plasma.
2405.08081
Giovani Dalla Valle Garcia
Giovani Dalla Valle Garcia, Felix Kahlhoefer, Maksym Ovchynnikov, Thomas Schwetz
Not-so-inelastic Dark Matter
20 pages, 7 figures, appendices
null
null
P3H-24-028, TTP24-011
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
Models of inelastic (or pseudo-Dirac) dark matter commonly assume an accidental symmetry between the left-handed and right-handed mass terms in order to suppress diagonal couplings. We point out that this symmetry is unnecessary, because for Majorana fermions the diagonal couplings are not strongly constrained. Removing the requirement of such an ad-hoc symmetry instead relaxes the relic density constraint due to additional annihilation modes. We consider a simple UV-complete model realising this setup and study constraints from (in)direct detection, beam dump experiments and colliders. We identify two viable mass regions for the dark matter mass, around a few hundred MeV and around a few GeV, respectively. The former region will be fully tested by near-future analyses of NA64 and Belle II data, while the latter turns out to be challenging to explore even with future experiments.
[ { "created": "Mon, 13 May 2024 18:00:41 GMT", "version": "v1" } ]
2024-05-15
[ [ "Garcia", "Giovani Dalla Valle", "" ], [ "Kahlhoefer", "Felix", "" ], [ "Ovchynnikov", "Maksym", "" ], [ "Schwetz", "Thomas", "" ] ]
Models of inelastic (or pseudo-Dirac) dark matter commonly assume an accidental symmetry between the left-handed and right-handed mass terms in order to suppress diagonal couplings. We point out that this symmetry is unnecessary, because for Majorana fermions the diagonal couplings are not strongly constrained. Removing the requirement of such an ad-hoc symmetry instead relaxes the relic density constraint due to additional annihilation modes. We consider a simple UV-complete model realising this setup and study constraints from (in)direct detection, beam dump experiments and colliders. We identify two viable mass regions for the dark matter mass, around a few hundred MeV and around a few GeV, respectively. The former region will be fully tested by near-future analyses of NA64 and Belle II data, while the latter turns out to be challenging to explore even with future experiments.
hep-ph/0606195
Andrea Bianconi
Andrea Bianconi
A study on the feasibility of a precise measurement of the $\tau$-dependence of the cross sections for Drell-Yan experiments at moderate energies
4 pages, 4 figures, in print on Physical Review D
Phys.Rev.D74:057501,2006
10.1103/PhysRevD.74.057501
null
hep-ph
null
Recently, a reconsideration of Drell-Yan cross sections at moderate energies and masses has suggested the possibility of relevant enhancements of the cross sections in some kinematical regions. If confirmed, these predictions could largely affect the planning of Drell-Yan experiments aimed at transverse spin measurements after 2010. More in general, the problem is present of a precision measurement of the $\tau$ dependence of Drell-Yan cross sections. Here we discuss the feasibility of such a measurement within short time at the COMPASS apparatus, and its relevance for the PANDA experiment.
[ { "created": "Mon, 19 Jun 2006 12:47:52 GMT", "version": "v1" }, { "created": "Wed, 30 Aug 2006 08:16:27 GMT", "version": "v2" } ]
2008-11-26
[ [ "Bianconi", "Andrea", "" ] ]
Recently, a reconsideration of Drell-Yan cross sections at moderate energies and masses has suggested the possibility of relevant enhancements of the cross sections in some kinematical regions. If confirmed, these predictions could largely affect the planning of Drell-Yan experiments aimed at transverse spin measurements after 2010. More in general, the problem is present of a precision measurement of the $\tau$ dependence of Drell-Yan cross sections. Here we discuss the feasibility of such a measurement within short time at the COMPASS apparatus, and its relevance for the PANDA experiment.
hep-ph/9711204
Long Hoang Ngoc
Hoang Ngoc Long
Scalar sector of the 3 3 1 model with three Higgs triplets
9 pages, latex, no figures
Mod.Phys.Lett.A13:1865-1874,1998
10.1142/S0217732398001959
IC/97/165
hep-ph
null
A scalar sector of the 3 3 1 model with three Higgs triplets is considered. The mass spectrum, eigenstates and interactions of the Higgs and the SM gauge bosons are derived. We show that one of the neutral scalars can be identified with the standard model Higgs boson, and in the considered potential there is no mixing between scalars having VEV and ones without VEV.
[ { "created": "Mon, 3 Nov 1997 10:06:20 GMT", "version": "v1" } ]
2008-11-26
[ [ "Long", "Hoang Ngoc", "" ] ]
A scalar sector of the 3 3 1 model with three Higgs triplets is considered. The mass spectrum, eigenstates and interactions of the Higgs and the SM gauge bosons are derived. We show that one of the neutral scalars can be identified with the standard model Higgs boson, and in the considered potential there is no mixing between scalars having VEV and ones without VEV.
hep-ph/0501151
Laura Tolos
L. Tolos, J. Schaffner-Bielich and A. Mishra
D-mesons in dense nuclear matter
4 pages, 4 figures, to appear in the proceedings of Hard Probes 2004, Ericeira, Portugal, November 4-10, 2004 (European Physical Journal C)
Eur.Phys.J.C43:127-130,2005
10.1140/epjc/s2005-02254-5
null
hep-ph nucl-th
null
The D-meson properties in dense nuclear matter are studied. The D-meson spectral density is obtained within the framework of a coupled-channel self-consistent calculation assuming, as bare meson-baryon interaction, a separable potential. The $\Lambda_c(2593)$ resonance is generated dynamically in our coupled-channel model. The medium modifications of the D-meson properties due to Pauli blocking and the dressing of D-mesons, nucleons and pions are also studied. We conclude that the self-consistent coupled-channel process reduces the in-medium effects on the D-meson compared to previous literature which do not considered the coupled-channel structure
[ { "created": "Mon, 17 Jan 2005 10:55:04 GMT", "version": "v1" } ]
2009-01-07
[ [ "Tolos", "L.", "" ], [ "Schaffner-Bielich", "J.", "" ], [ "Mishra", "A.", "" ] ]
The D-meson properties in dense nuclear matter are studied. The D-meson spectral density is obtained within the framework of a coupled-channel self-consistent calculation assuming, as bare meson-baryon interaction, a separable potential. The $\Lambda_c(2593)$ resonance is generated dynamically in our coupled-channel model. The medium modifications of the D-meson properties due to Pauli blocking and the dressing of D-mesons, nucleons and pions are also studied. We conclude that the self-consistent coupled-channel process reduces the in-medium effects on the D-meson compared to previous literature which do not considered the coupled-channel structure
1708.04909
Yufeng Li
Jian Tang, Yibing Zhang, Yu-Feng Li
Probing Direct and Indirect Unitarity Violation in Future Accelerator Neutrino Facilities
19 pages, 6 figures
null
10.1016/j.physletb.2017.09.055
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The possible existence of light and heavy sterile neutrinos may give rise to direct and indirect unitarity violation of the $3\times3$ lepton mixing matrix respectively. In the current work we study the potential of future accelerator neutrino facilities in probing the unitarity violation effects. Taking DUNE, T2HK and a low-energy Neutrino Factory (LENF) as working examples of future accelerator neutrino facilities, we study the distinct effects of direct and indirect unitarity violation on the discovery reach of the leptonic CP violation and precision measurements of $\theta_{23}$ in the three neutrino framework. In addition, constraints on the additional mixing parameters of direct and indirect unitarity violation are also discussed. Finally, we stress that the combination of experiments with different oscillation channels, different neutrino beams and different detector techniques will be an effective solution to the parameter degeneracy problem and give the robust measurement of leptonic CP violation even if the direct and indirect unitarity violation are taken into account.
[ { "created": "Wed, 16 Aug 2017 14:31:37 GMT", "version": "v1" } ]
2017-11-22
[ [ "Tang", "Jian", "" ], [ "Zhang", "Yibing", "" ], [ "Li", "Yu-Feng", "" ] ]
The possible existence of light and heavy sterile neutrinos may give rise to direct and indirect unitarity violation of the $3\times3$ lepton mixing matrix respectively. In the current work we study the potential of future accelerator neutrino facilities in probing the unitarity violation effects. Taking DUNE, T2HK and a low-energy Neutrino Factory (LENF) as working examples of future accelerator neutrino facilities, we study the distinct effects of direct and indirect unitarity violation on the discovery reach of the leptonic CP violation and precision measurements of $\theta_{23}$ in the three neutrino framework. In addition, constraints on the additional mixing parameters of direct and indirect unitarity violation are also discussed. Finally, we stress that the combination of experiments with different oscillation channels, different neutrino beams and different detector techniques will be an effective solution to the parameter degeneracy problem and give the robust measurement of leptonic CP violation even if the direct and indirect unitarity violation are taken into account.
hep-ph/0409096
Mu-Chun Chen
Mu-Chun Chen and K.T. Mahanthappa
Lepton Flavor Violating Decays, Soft Leptogenesis and SUSY SO(10)
RevTeX, 22 pages, 9 figures; v2: references added, version to appear in Phys. Rev. D
Phys.Rev. D70 (2004) 113013
10.1103/PhysRevD.70.113013
BNL-HET-04/14, COLO-HEP-502
hep-ph
null
We investigate lepton flavor violating decays in a SUSY SO(10) model with symmetric textures recently constructed by us. Unlike the models with lop-sided textures which give rise to a large decay rate for mu -> e gamma, the decay rate we get is much suppressed and yet it is large enough to be accessible to the next generation of experiments. We have also investigated the possibility of baryogenesis resulting from soft leptogenesis. We find that with the soft SUSY masses assuming their natural values, B^\prime \equiv \sqrt{BM_{1}} ~ 1.4 TeV and Im(A) ~ 1 TeV, the observed baryon asymmetry in the Universe can be accommodated in our model. We have also updated the predictions of our model for the masses, mixing angles and CP violating measures in both charged fermion and neutrino sectors, using the most up-to-date experimental data as input.
[ { "created": "Wed, 8 Sep 2004 19:27:01 GMT", "version": "v1" }, { "created": "Wed, 13 Oct 2004 22:05:51 GMT", "version": "v2" } ]
2009-11-10
[ [ "Chen", "Mu-Chun", "" ], [ "Mahanthappa", "K. T.", "" ] ]
We investigate lepton flavor violating decays in a SUSY SO(10) model with symmetric textures recently constructed by us. Unlike the models with lop-sided textures which give rise to a large decay rate for mu -> e gamma, the decay rate we get is much suppressed and yet it is large enough to be accessible to the next generation of experiments. We have also investigated the possibility of baryogenesis resulting from soft leptogenesis. We find that with the soft SUSY masses assuming their natural values, B^\prime \equiv \sqrt{BM_{1}} ~ 1.4 TeV and Im(A) ~ 1 TeV, the observed baryon asymmetry in the Universe can be accommodated in our model. We have also updated the predictions of our model for the masses, mixing angles and CP violating measures in both charged fermion and neutrino sectors, using the most up-to-date experimental data as input.
2311.07347
Shao-Jiang Wang
Jun-Chen Wang, Zi-Yan Yuwen, Yu-Shi Hao, Shao-Jiang Wang
General bubble expansion at strong coupling
v1, 22 pages, 10 figures; v2, two columns, 16 pages, 8 figures, extended discussion on the difference between phase pressure difference and wall pressure difference, version accepted for publication in Physical Review D; v3, to match the published version
Phys. Rev. D 109 (2024) 9, 096012
10.1103/PhysRevD.109.096012
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The strongly coupled system like the quark-hadron transition (if it is of first order) is becoming an active play yard for the physics of cosmological first-order phase transitions. However, the traditional field theoretic approach to strongly coupled first-order phase transitions is of great challenge, driving recent efforts from holographic dual theories with explicit numerical simulations. These holographic numerical simulations have revealed an intriguing linear correlation between the phase pressure difference (pressure difference away from the wall) to the nonrelativistic terminal velocity of an expanding planar wall, which has been reproduced analytically alongside both cylindrical and spherical walls from perfect-fluid hydrodynamics in our previous study but only for a bag equation of state. We also found, in our previous study, a universal quadratic correlation between the wall pressure difference (pressure difference near the bubble wall) to the nonrelativistic terminal wall velocity regardless of wall geometries. In this paper, we will generalize these analytic relations between the phase/wall pressure difference and terminal wall velocity into a more realistic equation of state beyond the simple bag model, providing the most general predictions so far for future tests from holographic numerical simulations of strongly coupled first-order phase transitions
[ { "created": "Mon, 13 Nov 2023 14:05:20 GMT", "version": "v1" }, { "created": "Wed, 1 May 2024 17:02:42 GMT", "version": "v2" }, { "created": "Sat, 11 May 2024 16:26:11 GMT", "version": "v3" } ]
2024-05-14
[ [ "Wang", "Jun-Chen", "" ], [ "Yuwen", "Zi-Yan", "" ], [ "Hao", "Yu-Shi", "" ], [ "Wang", "Shao-Jiang", "" ] ]
The strongly coupled system like the quark-hadron transition (if it is of first order) is becoming an active play yard for the physics of cosmological first-order phase transitions. However, the traditional field theoretic approach to strongly coupled first-order phase transitions is of great challenge, driving recent efforts from holographic dual theories with explicit numerical simulations. These holographic numerical simulations have revealed an intriguing linear correlation between the phase pressure difference (pressure difference away from the wall) to the nonrelativistic terminal velocity of an expanding planar wall, which has been reproduced analytically alongside both cylindrical and spherical walls from perfect-fluid hydrodynamics in our previous study but only for a bag equation of state. We also found, in our previous study, a universal quadratic correlation between the wall pressure difference (pressure difference near the bubble wall) to the nonrelativistic terminal wall velocity regardless of wall geometries. In this paper, we will generalize these analytic relations between the phase/wall pressure difference and terminal wall velocity into a more realistic equation of state beyond the simple bag model, providing the most general predictions so far for future tests from holographic numerical simulations of strongly coupled first-order phase transitions
hep-ph/9305317
null
B.K. Jennings (Triumf, 4004 Wesbrook Mall, Vancouver, B.C., V6T 2A3, Canada) and G.A. Miller (Department of Physics, FM-15, University of Washington, Seattle, WA, USA)
Natural Color Transparency in High Energy (p,pp) Reactions
latex file, 13 pages, 4 figures appended as ps files, look for "cut here ..." 1993 Univ. of Washington preprint 404427-00-N93-11
Phys.Lett.B318:7-13,1993
10.1016/0370-2693(93)91774-H
null
hep-ph nucl-th
null
New parameter free calculations including a variety of necessary kinematic and dynamic effects show that the results of BNL $(p,2p)$ measurements are consistent with the expectations of color transparency.
[ { "created": "Tue, 25 May 1993 23:48:03 GMT", "version": "v1" } ]
2009-09-25
[ [ "Jennings", "B. K.", "", "Triumf, 4004 Wesbrook Mall, Vancouver, B.C., V6T 2A3,\n Canada" ], [ "Miller", "G. A.", "", "Department of Physics, FM-15, University of\n Washington, Seattle, WA, USA" ] ]
New parameter free calculations including a variety of necessary kinematic and dynamic effects show that the results of BNL $(p,2p)$ measurements are consistent with the expectations of color transparency.
hep-ph/9808301
null
R. N. Mohapatra and S. Nussinov
Gauge Model for Maximal Neutrino Mixing
6 pages, one figure; References fixed
Phys.Lett. B441 (1998) 299-304
10.1016/S0370-2693(98)01169-1
null
hep-ph
null
The recently announced Super-Kamiokande data on atmospheric neutrino oscillation seems to require a maximal mixing between the $\nu_{\mu}$ and $\nu_{\tau}$ within the conventional three neutrino picture. It is then tempting to suggest as has been done in literature, that the solar neutrino deficit be also understood as resulting from a maximal mixing between $\nu_e$ and $\nu_{\mu}$. In this letter, we propose a left-right symmetric extension of the standard model where permutation symmetry leads to one of the maximal mixing patterns in a technically natural manner. The double seesaw mechanism gives small Majorana masses for neutrinos needed to understand the atmospheric as well as the solar neutrino puzzles.
[ { "created": "Tue, 11 Aug 1998 18:46:03 GMT", "version": "v1" }, { "created": "Tue, 18 Aug 1998 17:51:21 GMT", "version": "v2" } ]
2009-10-31
[ [ "Mohapatra", "R. N.", "" ], [ "Nussinov", "S.", "" ] ]
The recently announced Super-Kamiokande data on atmospheric neutrino oscillation seems to require a maximal mixing between the $\nu_{\mu}$ and $\nu_{\tau}$ within the conventional three neutrino picture. It is then tempting to suggest as has been done in literature, that the solar neutrino deficit be also understood as resulting from a maximal mixing between $\nu_e$ and $\nu_{\mu}$. In this letter, we propose a left-right symmetric extension of the standard model where permutation symmetry leads to one of the maximal mixing patterns in a technically natural manner. The double seesaw mechanism gives small Majorana masses for neutrinos needed to understand the atmospheric as well as the solar neutrino puzzles.
1011.1248
A. H. Rezaeian
Andrey Kormilitzin, Eugene Levin, Amir H. Rezaeian
On the Nuclear Modification Factor at RHIC and LHC
14 pages, 10 figures; v2: results unchanged, more discussion and references added. The version to appear in Nucl. Phys. A
Nucl.Phys.A860:84-101,2011
10.1016/j.nuclphysa.2011.05.009
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that pQCD factorization incorporated with pre-haronization energy-loss effect naturally leads to flatness of the nuclear modification factor R_{AA} for produced hadrons at high transverse momentum p_T. We consider two possible scenarios for the pre-hadronization: In scenario 1, the produced gluon propagates through dense QCD medium and loses energy. In scenario 2, all gluons first decay to quark-antiquark pairs and then each pair loses energy as propagating through the medium. We show that the estimates of the energy-loss in these two different models lead to very close values and is able to explain the suppression of high-p_T hadrons in nucleus-nucleus collisions at RHIC. We show that the onset of the flatness of R_{AA} for the produced hadron in central collisions at midrapidity is about p_T\approx 15 and 25 GeV at RHIC and the LHC energies, respectively. We show that the smallness (R_{AA}<0.5) and the high-p_T flatness of R_{AA} obtained from the k_T factorization supplemented with the Balitsky-Kovchegov (BK) equation is rather generic and it does not strongly depend on the details of the BK solutions. We show that energy-loss effect reduces the nuclear modification factor obtained from the k_T factorization about 30\div 50% at moderate p_T.
[ { "created": "Thu, 4 Nov 2010 19:49:32 GMT", "version": "v1" }, { "created": "Mon, 16 May 2011 21:01:01 GMT", "version": "v2" } ]
2015-03-17
[ [ "Kormilitzin", "Andrey", "" ], [ "Levin", "Eugene", "" ], [ "Rezaeian", "Amir H.", "" ] ]
We show that pQCD factorization incorporated with pre-haronization energy-loss effect naturally leads to flatness of the nuclear modification factor R_{AA} for produced hadrons at high transverse momentum p_T. We consider two possible scenarios for the pre-hadronization: In scenario 1, the produced gluon propagates through dense QCD medium and loses energy. In scenario 2, all gluons first decay to quark-antiquark pairs and then each pair loses energy as propagating through the medium. We show that the estimates of the energy-loss in these two different models lead to very close values and is able to explain the suppression of high-p_T hadrons in nucleus-nucleus collisions at RHIC. We show that the onset of the flatness of R_{AA} for the produced hadron in central collisions at midrapidity is about p_T\approx 15 and 25 GeV at RHIC and the LHC energies, respectively. We show that the smallness (R_{AA}<0.5) and the high-p_T flatness of R_{AA} obtained from the k_T factorization supplemented with the Balitsky-Kovchegov (BK) equation is rather generic and it does not strongly depend on the details of the BK solutions. We show that energy-loss effect reduces the nuclear modification factor obtained from the k_T factorization about 30\div 50% at moderate p_T.
1401.6269
Xing-Gang Wu
Gu Chen, Xing-Gang Wu, Jia-Wei Zhang, Hua-Yong Han and Hai-Bing Fu
Hadronic production of $\Xi_{cc}$ at a fixed-target experiment at the LHC
6 pages, 7 figures. References updated and discussions improved. To be published in Phys.Rev.D
Phys. Rev. D 89 (2014) 074020
10.1103/PhysRevD.89.074020
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the paper, we present a detailed discussion on the $\Xi_{cc}$ production at a fixed target experiment at the LHC (After@LHC). The doubly charmed baryon $\Xi_{cc}$ is produced via the channel, ${\rm Proton} + {\rm Proton}\to\Xi_{cc}+X$. In estimating its hadroproduction, we discuss three dominant subprocesses, e.g. $g+g\to \Xi_{cc} +\bar{c} +\bar{c}$, $g+c\to \Xi_{cc}+\bar{c}$ and $c+c\to \Xi_{cc}+g$. During the production, it shall first generate a binding diquark and then form the $\Xi_{cc}$ baryon by grabbing soft light-quarks or gluons. We observe that both the two diquark configurations $(cc)[^3S_1]_{\bf\bar 3}$ and $(cc)[^1S_0]_{\bf 6}$ can have sizable contributions to the $\Xi_{cc}$ production. Large number of $\Xi_{cc}$ events can be generated at the After@LHC, whose total production cross section is larger than that of the SELEX experiment by about thirty-five times. It may also possible to study the properties of $\Xi_{bc}$ at the After@LHC. More specifically, we shall have about $8.3 \times 10^6$ $\Xi_{cc}$ events/year and $1.8 \times 10^4$ $\Xi_{bc}$ events/year when its integrated luminosity approaches to $2$ fb$^{-1}$/year. Thus, in addition to SELEX and LHC, the After@LHC shall provide another useful platform for studying the baryon properties.
[ { "created": "Fri, 24 Jan 2014 07:07:35 GMT", "version": "v1" }, { "created": "Tue, 25 Mar 2014 17:26:32 GMT", "version": "v2" } ]
2014-04-10
[ [ "Chen", "Gu", "" ], [ "Wu", "Xing-Gang", "" ], [ "Zhang", "Jia-Wei", "" ], [ "Han", "Hua-Yong", "" ], [ "Fu", "Hai-Bing", "" ] ]
In the paper, we present a detailed discussion on the $\Xi_{cc}$ production at a fixed target experiment at the LHC (After@LHC). The doubly charmed baryon $\Xi_{cc}$ is produced via the channel, ${\rm Proton} + {\rm Proton}\to\Xi_{cc}+X$. In estimating its hadroproduction, we discuss three dominant subprocesses, e.g. $g+g\to \Xi_{cc} +\bar{c} +\bar{c}$, $g+c\to \Xi_{cc}+\bar{c}$ and $c+c\to \Xi_{cc}+g$. During the production, it shall first generate a binding diquark and then form the $\Xi_{cc}$ baryon by grabbing soft light-quarks or gluons. We observe that both the two diquark configurations $(cc)[^3S_1]_{\bf\bar 3}$ and $(cc)[^1S_0]_{\bf 6}$ can have sizable contributions to the $\Xi_{cc}$ production. Large number of $\Xi_{cc}$ events can be generated at the After@LHC, whose total production cross section is larger than that of the SELEX experiment by about thirty-five times. It may also possible to study the properties of $\Xi_{bc}$ at the After@LHC. More specifically, we shall have about $8.3 \times 10^6$ $\Xi_{cc}$ events/year and $1.8 \times 10^4$ $\Xi_{bc}$ events/year when its integrated luminosity approaches to $2$ fb$^{-1}$/year. Thus, in addition to SELEX and LHC, the After@LHC shall provide another useful platform for studying the baryon properties.
2107.06625
Daniel Ma\^itre
Daniel Ma\^itre and Henry Truong
A factorisation-aware Matrix element emulator
24 pages, 8 figures, v2 accepted for publication in JHEP
null
10.1007/JHEP11(2021)066
IPPP/21/11
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article we present a neural network based model to emulate matrix elements. This model improves on existing methods by taking advantage of the known factorisation properties of matrix elements. In so doing we can control the behaviour of simulated matrix elements when extrapolating into more singular regions than the ones used for training the neural network. We apply our model to the case of leading-order jet production in $e^+e^-$ collisions with up to five jets. Our results show that this model can reproduce the matrix elements with errors below the one-percent level on the phase-space covered during fitting and testing, and a robust extrapolation to the parts of the phase-space where the matrix elements are more singular than seen at the fitting stage.
[ { "created": "Wed, 14 Jul 2021 11:58:47 GMT", "version": "v1" }, { "created": "Fri, 29 Oct 2021 16:07:30 GMT", "version": "v2" } ]
2021-12-01
[ [ "Maître", "Daniel", "" ], [ "Truong", "Henry", "" ] ]
In this article we present a neural network based model to emulate matrix elements. This model improves on existing methods by taking advantage of the known factorisation properties of matrix elements. In so doing we can control the behaviour of simulated matrix elements when extrapolating into more singular regions than the ones used for training the neural network. We apply our model to the case of leading-order jet production in $e^+e^-$ collisions with up to five jets. Our results show that this model can reproduce the matrix elements with errors below the one-percent level on the phase-space covered during fitting and testing, and a robust extrapolation to the parts of the phase-space where the matrix elements are more singular than seen at the fitting stage.
1312.5214
Thomas Hambye
Thomas Hambye
Charged lepton flavor violation and the origin of neutrino masses
Review talk given at the "1st Conference on Charged Lepton Flavor Violation", May 6-8 2013, Lecce, Italy
null
null
ULB-TH/13-16
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The neutrino oscillations imply that charged lepton flavor violation (CLFV) processes do exist. Even if the associated rates are in general expected very suppressed, it turns out that this is not always necessarily the case. In the framework of the three basic seesaw models, we review the possibilities of having observable rates and thus, in this way, of distinguishing these possible neutrino mass origins.
[ { "created": "Wed, 18 Dec 2013 16:40:38 GMT", "version": "v1" } ]
2013-12-19
[ [ "Hambye", "Thomas", "" ] ]
The neutrino oscillations imply that charged lepton flavor violation (CLFV) processes do exist. Even if the associated rates are in general expected very suppressed, it turns out that this is not always necessarily the case. In the framework of the three basic seesaw models, we review the possibilities of having observable rates and thus, in this way, of distinguishing these possible neutrino mass origins.
hep-ph/0306189
Eun-Joo Ahn
Eun-Joo Ahn, Marco Cavaglia
Cosmic Black Holes
7 pages. Essay submitted to the 2003 Gravity Research Foundation essay competition. Received an honorable mention. Accepted for publication in IJMP D
Int.J.Mod.Phys.D12:1699-1704,2003
10.1142/S0218271803004006
null
hep-ph astro-ph gr-qc hep-th
null
Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be the only tool to explore thermalisation of the early universe. Whereas the creation of cosmic black holes was active in the past, it seems to be negligible at the present epoch.
[ { "created": "Fri, 20 Jun 2003 18:52:30 GMT", "version": "v1" } ]
2011-05-12
[ [ "Ahn", "Eun-Joo", "" ], [ "Cavaglia", "Marco", "" ] ]
Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be the only tool to explore thermalisation of the early universe. Whereas the creation of cosmic black holes was active in the past, it seems to be negligible at the present epoch.
2107.04578
Kai Schmitz
Wilfried Buchmuller, Valerie Domcke, Kai Schmitz
Stochastic gravitational-wave background from metastable cosmic strings
31 pages, 6 figures. v2: signal recently reported by the Parkes Pulsar Timing Array (PPTA) collaboration [2107.12112] added to Figs. 2 to 4
null
10.1088/1475-7516/2021/12/006
CERN-TH-2021-107, DESY 21-101
hep-ph astro-ph.CO gr-qc
http://creativecommons.org/licenses/by/4.0/
A metastable cosmic-string network is a generic consequence of many grand unified theories (GUTs) when combined with cosmic inflation. Metastable cosmic strings are not topologically stable, but decay on cosmic time scales due to pair production of GUT monopoles. This leads to a network consisting of metastable long strings on superhorizon scales as well as of string loops and segments on subhorizon scales. We compute for the first time the complete stochastic gravitational-wave background (SGWB) arising from all these network constituents, including several technical improvements to both the derivation of the loop and segment contributions. We find that the gravitational waves emitted by string loops provide the main contribution to the gravitational-wave spectrum in the relevant parameter space. The resulting spectrum is consistent with the tentative signal observed by the NANOGrav and Parkes pulsar timing collaborations for a string tension of G\mu ~ 10^-11...-7 and has ample discovery space for ground- and space-based detectors. For GUT-scale string tensions, G\mu ~ 10^-8...-7, metastable strings predict a SGWB in the LIGO-Virgo-KAGRA band that could be discovered in the near future.
[ { "created": "Fri, 9 Jul 2021 17:53:13 GMT", "version": "v1" }, { "created": "Sat, 14 Aug 2021 19:21:53 GMT", "version": "v2" } ]
2021-12-15
[ [ "Buchmuller", "Wilfried", "" ], [ "Domcke", "Valerie", "" ], [ "Schmitz", "Kai", "" ] ]
A metastable cosmic-string network is a generic consequence of many grand unified theories (GUTs) when combined with cosmic inflation. Metastable cosmic strings are not topologically stable, but decay on cosmic time scales due to pair production of GUT monopoles. This leads to a network consisting of metastable long strings on superhorizon scales as well as of string loops and segments on subhorizon scales. We compute for the first time the complete stochastic gravitational-wave background (SGWB) arising from all these network constituents, including several technical improvements to both the derivation of the loop and segment contributions. We find that the gravitational waves emitted by string loops provide the main contribution to the gravitational-wave spectrum in the relevant parameter space. The resulting spectrum is consistent with the tentative signal observed by the NANOGrav and Parkes pulsar timing collaborations for a string tension of G\mu ~ 10^-11...-7 and has ample discovery space for ground- and space-based detectors. For GUT-scale string tensions, G\mu ~ 10^-8...-7, metastable strings predict a SGWB in the LIGO-Virgo-KAGRA band that could be discovered in the near future.
0907.0859
Long Hoang Ngoc
P. V. Dong, L. T. Hue, H. T. Hung, H. N. Long, and N. H. Thao
Symmetry Factors of Feynman Diagrams for Scalar Fields
Journal version, new references added
Theor.Math.Phys.165:1500-1511,2010
10.1007/s11232-010-0124-1
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The symmetry factor of Feynman diagrams for real and complex scalar fields is presented. Being analysis of Wick expansion for Green functions, the mentioned factor is derived in a general form. The symmetry factor can be separated into two ones corresponding to that of connected and vacuum diagrams. The determination of symmetry factors for the vacuum diagrams is necessary as they play a role in the effective action and phase transitions in cosmology. In the complex scalar theory the diagrams different in topology may give the same contribution, hence inverse of the symmetry factor (1/S) for total contribution is a summation of each similar ones (1/S_i), i.e., 1/S = \sum_i (1/S_i).
[ { "created": "Sun, 5 Jul 2009 14:07:05 GMT", "version": "v1" }, { "created": "Mon, 15 Nov 2010 07:23:38 GMT", "version": "v2" } ]
2011-01-17
[ [ "Dong", "P. V.", "" ], [ "Hue", "L. T.", "" ], [ "Hung", "H. T.", "" ], [ "Long", "H. N.", "" ], [ "Thao", "N. H.", "" ] ]
The symmetry factor of Feynman diagrams for real and complex scalar fields is presented. Being analysis of Wick expansion for Green functions, the mentioned factor is derived in a general form. The symmetry factor can be separated into two ones corresponding to that of connected and vacuum diagrams. The determination of symmetry factors for the vacuum diagrams is necessary as they play a role in the effective action and phase transitions in cosmology. In the complex scalar theory the diagrams different in topology may give the same contribution, hence inverse of the symmetry factor (1/S) for total contribution is a summation of each similar ones (1/S_i), i.e., 1/S = \sum_i (1/S_i).
hep-ph/0504087
Junfeng Sun
Gang Hao, Lin Li, Cong-Feng Qiao
Ds+ -- Ds- Asymmetry in Photoproduction
11 page, 5 figures
Phys.Lett.B621:139-144,2005
10.1016/j.physletb.2005.06.057
null
hep-ph
null
Considering of the possible difference in strange and antistrange quark distributions inside nucleon, we investigate the Ds+ -- Ds- asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We adopt two distribution models of strange sea, those are the light-cone meson-baryon fluctuation model and the effective chiral quark model. Our results show that the asymmetry induced by the strange quark distributions is distinct, which is measurable in experiments. And, there are evident differences between the predictions of our calculation and previous estimation. Therefore, the experimental measurements on the Ds+ -- Ds- asymmetry may impose a unique restriction on the strange-antistrange distribution asymmetry models.
[ { "created": "Tue, 12 Apr 2005 14:50:25 GMT", "version": "v1" }, { "created": "Sat, 4 Jun 2005 10:04:09 GMT", "version": "v2" } ]
2008-11-26
[ [ "Hao", "Gang", "" ], [ "Li", "Lin", "" ], [ "Qiao", "Cong-Feng", "" ] ]
Considering of the possible difference in strange and antistrange quark distributions inside nucleon, we investigate the Ds+ -- Ds- asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We adopt two distribution models of strange sea, those are the light-cone meson-baryon fluctuation model and the effective chiral quark model. Our results show that the asymmetry induced by the strange quark distributions is distinct, which is measurable in experiments. And, there are evident differences between the predictions of our calculation and previous estimation. Therefore, the experimental measurements on the Ds+ -- Ds- asymmetry may impose a unique restriction on the strange-antistrange distribution asymmetry models.
1002.2495
Harmen J. Warringa
Kenji Fukushima, Dmitri E. Kharzeev, Harmen J. Warringa
Real-time dynamics of the Chiral Magnetic Effect
4 pages, 3 figures, Revtex
Phys.Rev.Lett.104:212001,2010
10.1103/PhysRevLett.104.212001
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In quantum chromodynamics, a gauge field configuration with nonzero topological charge generates a difference between the number of left- and right-handed quarks. When a (electromagnetic) magnetic field is added to this configuration, an electromagnetic current is induced along the magnetic field; this is called the chiral magnetic effect. We compute this current in the presence of a color flux tube possessing topological charge, with a magnetic field applied perpendicular to it. We argue that this situation is realized at the early stage of relativistic heavy-ion collisions.
[ { "created": "Fri, 12 Feb 2010 08:12:56 GMT", "version": "v1" } ]
2014-11-20
[ [ "Fukushima", "Kenji", "" ], [ "Kharzeev", "Dmitri E.", "" ], [ "Warringa", "Harmen J.", "" ] ]
In quantum chromodynamics, a gauge field configuration with nonzero topological charge generates a difference between the number of left- and right-handed quarks. When a (electromagnetic) magnetic field is added to this configuration, an electromagnetic current is induced along the magnetic field; this is called the chiral magnetic effect. We compute this current in the presence of a color flux tube possessing topological charge, with a magnetic field applied perpendicular to it. We argue that this situation is realized at the early stage of relativistic heavy-ion collisions.
2305.10497
Keping Xie
Keping Xie, Bei Zhou, T.J. Hobbs
The Photon Content of the Neutron
38 pages, 22 figures
null
null
ANL-182626, MSUHEP-24-004, PITT-PACC-2314
hep-ph astro-ph.HE nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we complete our CT18qed study with the neutron's photon parton distribution function (PDF), which is essential for the nucleus scattering phenomenology. Two methods, CT18lux and CT18qed, based on the LUXqed formalism and the DGLAP evolution, respectively, to determine the neutron's photon PDF have been presented. Various low-$Q^2$ non-perturbative variations have been carefully examined, which are treated as additional uncertainties on top of those induced by quark and gluon PDFs. The impacts of the momentum sum rule as well as isospin symmetry violation have been explored, and turn out to be negligible. A detailed comparison with other neutron's photon PDF sets has been performed, which shows a great improvement in the precision and a reasonable uncertainty estimation in our results. Finally, two phenomenological implications are demonstrated with photon-initiated processes: neutrino-nucleus $W$-boson production, which is important for the near-future TeV--PeV neutrino observations, and the axion-like particle production at a high-energy muon beam-dump experiment.
[ { "created": "Wed, 17 May 2023 18:05:50 GMT", "version": "v1" }, { "created": "Thu, 28 Mar 2024 19:41:43 GMT", "version": "v2" } ]
2024-04-01
[ [ "Xie", "Keping", "" ], [ "Zhou", "Bei", "" ], [ "Hobbs", "T. J.", "" ] ]
In this work, we complete our CT18qed study with the neutron's photon parton distribution function (PDF), which is essential for the nucleus scattering phenomenology. Two methods, CT18lux and CT18qed, based on the LUXqed formalism and the DGLAP evolution, respectively, to determine the neutron's photon PDF have been presented. Various low-$Q^2$ non-perturbative variations have been carefully examined, which are treated as additional uncertainties on top of those induced by quark and gluon PDFs. The impacts of the momentum sum rule as well as isospin symmetry violation have been explored, and turn out to be negligible. A detailed comparison with other neutron's photon PDF sets has been performed, which shows a great improvement in the precision and a reasonable uncertainty estimation in our results. Finally, two phenomenological implications are demonstrated with photon-initiated processes: neutrino-nucleus $W$-boson production, which is important for the near-future TeV--PeV neutrino observations, and the axion-like particle production at a high-energy muon beam-dump experiment.
2004.07573
Dmitri Melikhov
Dmitri Melikhov and Silvano Simula
Nonintegrable threshold singularities of two-point functions in perturbation theory
7 pages, Extended version, Proof by induction is given in Appendices A and B, Conclusions remain unchanged
Eur. Phys. J. Plus 136 (2021) 106
10.1140/epjp/s13360-020-01024-0
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In perturbation theory, the spectral densities of two-point functions develop non-integrable threshold singularities at higher orders. In QCD, such singularities emerge when calculating the diagrams in terms of the pole quark mass, and they become stronger when one rearranges the perturbative expansion in terms of the running quark mass. In this paper we discuss the proper way to handle such singularities.
[ { "created": "Thu, 16 Apr 2020 10:25:03 GMT", "version": "v1" }, { "created": "Fri, 26 Jun 2020 14:05:25 GMT", "version": "v2" }, { "created": "Wed, 12 Aug 2020 21:59:57 GMT", "version": "v3" }, { "created": "Fri, 9 Oct 2020 20:13:59 GMT", "version": "v4" } ]
2021-01-20
[ [ "Melikhov", "Dmitri", "" ], [ "Simula", "Silvano", "" ] ]
In perturbation theory, the spectral densities of two-point functions develop non-integrable threshold singularities at higher orders. In QCD, such singularities emerge when calculating the diagrams in terms of the pole quark mass, and they become stronger when one rearranges the perturbative expansion in terms of the running quark mass. In this paper we discuss the proper way to handle such singularities.
hep-ph/9707207
Martin Hirsch
M. Hirsch, H.V. Klapdor-Kleingrothaus and S.G. Kovalenko
R-parity Conserving Supersymmetry, Neutrino Mass and Neutrinoless Double Beta Decay
LATEX, 29 pages + 4 (uuencoded) figures appended
Phys.Rev. D57 (1998) 1947-1961
10.1103/PhysRevD.57.1947
null
hep-ph
null
We consider contributions of R-parity conserving softly broken supersymmetry (SUSY) to neutrinoless double beta ($\znbb$) decay via the (B-L)-violating sneutrino mass term. The latter is a generic ingredient of any weak-scale SUSY model with a Majorana neutrino mass. The new R-parity conserving SUSY contributions to $\znbb$ are realized at the level of box diagrams. We derive the effective Lagrangian describing the SUSY-box mechanism of $\znbb$-decay and the corresponding nuclear matrix elements. The 1-loop sneutrino contribution to the Majorana neutrino mass is also derived. Given the data on the $\znbb$-decay half-life of $^{76}$Ge and the neutrino mass we obtain constraints on the (B-L)-violating sneutrino mass. These constraints leave room for accelerator searches for certain manifestations of the 2nd and 3rd generation (B-L)-violating sneutrino mass term, but are most probably too tight for first generation (B-L)-violating sneutrino masses to be searched for directly.
[ { "created": "Tue, 1 Jul 1997 15:26:19 GMT", "version": "v1" } ]
2009-10-30
[ [ "Hirsch", "M.", "" ], [ "Klapdor-Kleingrothaus", "H. V.", "" ], [ "Kovalenko", "S. G.", "" ] ]
We consider contributions of R-parity conserving softly broken supersymmetry (SUSY) to neutrinoless double beta ($\znbb$) decay via the (B-L)-violating sneutrino mass term. The latter is a generic ingredient of any weak-scale SUSY model with a Majorana neutrino mass. The new R-parity conserving SUSY contributions to $\znbb$ are realized at the level of box diagrams. We derive the effective Lagrangian describing the SUSY-box mechanism of $\znbb$-decay and the corresponding nuclear matrix elements. The 1-loop sneutrino contribution to the Majorana neutrino mass is also derived. Given the data on the $\znbb$-decay half-life of $^{76}$Ge and the neutrino mass we obtain constraints on the (B-L)-violating sneutrino mass. These constraints leave room for accelerator searches for certain manifestations of the 2nd and 3rd generation (B-L)-violating sneutrino mass term, but are most probably too tight for first generation (B-L)-violating sneutrino masses to be searched for directly.
1204.1230
Xiao-Gang He
Guan-Nan Li, Hsiu-Hsien Lin, Dong Xu, Xiao-Gang He
The $\alpha$, $\beta$ and $\gamma$ parameterizations of CP violating CKM phase
14 page, 1 figure
null
10.1142/S0217751X13500140
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The CKM matrix describing quark mixing with three generations can be parameterized by three mixing angles and one CP violating phase. In most of the parameterizations, the CP violating phase chosen is not a directly measurable quantity and is parametrization dependent. In this work, we propose to use experimentally measurable CP violating quantities, $\alpha$, $\beta$ or $\gamma$ in the unitarity triangle as the phase in the CKM matrix, and construct explicit $\alpha$, $\beta$ and $\gamma$ parameterizations. Approximate Wolfenstein-like expressions are also suggested.
[ { "created": "Thu, 5 Apr 2012 13:54:00 GMT", "version": "v1" } ]
2015-06-04
[ [ "Li", "Guan-Nan", "" ], [ "Lin", "Hsiu-Hsien", "" ], [ "Xu", "Dong", "" ], [ "He", "Xiao-Gang", "" ] ]
The CKM matrix describing quark mixing with three generations can be parameterized by three mixing angles and one CP violating phase. In most of the parameterizations, the CP violating phase chosen is not a directly measurable quantity and is parametrization dependent. In this work, we propose to use experimentally measurable CP violating quantities, $\alpha$, $\beta$ or $\gamma$ in the unitarity triangle as the phase in the CKM matrix, and construct explicit $\alpha$, $\beta$ and $\gamma$ parameterizations. Approximate Wolfenstein-like expressions are also suggested.
hep-ph/0703047
Jonathan M. Flynn
Jonathan M Flynn (1), Juan Nieves (2) ((1) University of Southampton, (2) Universidad de Granada)
Elastic s-wave B pi, D pi, D K and K pi scattering from lattice calculations of scalar form factors in semileptonic decays
16 pages, LaTeX, 5 figures: version accepted for publication
Phys.Rev.D75:074024,2007
10.1103/PhysRevD.75.074024
null
hep-ph
null
We show how theoretical, principally lattice, calculations of the scalar form factors in semileptonic pseudoscalar-to-pseudoscalar decays can be used to extract information about the corresponding elastic s-wave scattering channels. We find values for the scattering lengths m_pi a = 0.179(17)(14), 0.26(26) and 0.29(4) for elastic s-wave isospin-1/2 K pi, B pi and D pi channels respectively. We also determine phase shifts. For the D K channel we find hints that there is a bound state which can be identified with the recently discovered D_{s0}^+(2317).
[ { "created": "Mon, 5 Mar 2007 11:37:53 GMT", "version": "v1" }, { "created": "Mon, 9 Apr 2007 09:02:17 GMT", "version": "v2" } ]
2008-11-26
[ [ "Flynn", "Jonathan M", "" ], [ "Nieves", "Juan", "" ] ]
We show how theoretical, principally lattice, calculations of the scalar form factors in semileptonic pseudoscalar-to-pseudoscalar decays can be used to extract information about the corresponding elastic s-wave scattering channels. We find values for the scattering lengths m_pi a = 0.179(17)(14), 0.26(26) and 0.29(4) for elastic s-wave isospin-1/2 K pi, B pi and D pi channels respectively. We also determine phase shifts. For the D K channel we find hints that there is a bound state which can be identified with the recently discovered D_{s0}^+(2317).
hep-ph/9910534
Martin Beneke
M. Beneke (CERN)
Top quark production near threshold
8 pages, LaTeX, Talk presented at the High Energy Physics International Euroconference on Quantum Chromodynamics (QCD'99), Montpellier, France, 7-13 July 1999
Nucl.Phys.Proc.Suppl. 86 (2000) 547-554
10.1016/S0920-5632(00)00621-6
CERN-TH/99-281
hep-ph
null
The present theoretical status of top quark pair production near threshold at (future) $e^+ e^-$ ($\mu^+\mu^-$) colliders is summarized.
[ { "created": "Thu, 28 Oct 1999 15:37:04 GMT", "version": "v1" } ]
2009-10-31
[ [ "Beneke", "M.", "", "CERN" ] ]
The present theoretical status of top quark pair production near threshold at (future) $e^+ e^-$ ($\mu^+\mu^-$) colliders is summarized.
1311.4732
Jialun Ping
Hongxia Huang, Jialun Ping and Fan Wang
Possible $H$-like dibaryon states with heavy quarks
6 pages, 4 figures, 3 tables
Phys. Rev. C 89, 035201 (2014)
10.1103/PhysRevC.89.035201
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Possible $H$-like dibaryon states $\Lambda_{c}\Lambda_{c}$ and $\Lambda_{b}\Lambda_{b}$ are investigated within the framework of quark delocalization color screening model. The results show that the interaction between two $\Lambda_{c}$'s is repulsive, so it cannot be bound state by itself. However, the strong attraction in $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ channels and the strong channel coupling, due to the central interaction of one-gluon-exchange and one-pion-exchange, among $\Lambda_{c}\Lambda_{c}$, $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ push the energy of system below the threshold of $\Lambda_{c}\Lambda_{c}$ by $22$ MeV. The corresponding system $\Lambda_{b}\Lambda_{b}$ has the similar properties as that of $\Lambda_{c}\Lambda_{c}$ system, and a bound state is also possible in $\Lambda_{b}\Lambda_{b}$ system.
[ { "created": "Tue, 19 Nov 2013 13:30:36 GMT", "version": "v1" } ]
2014-03-12
[ [ "Huang", "Hongxia", "" ], [ "Ping", "Jialun", "" ], [ "Wang", "Fan", "" ] ]
Possible $H$-like dibaryon states $\Lambda_{c}\Lambda_{c}$ and $\Lambda_{b}\Lambda_{b}$ are investigated within the framework of quark delocalization color screening model. The results show that the interaction between two $\Lambda_{c}$'s is repulsive, so it cannot be bound state by itself. However, the strong attraction in $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ channels and the strong channel coupling, due to the central interaction of one-gluon-exchange and one-pion-exchange, among $\Lambda_{c}\Lambda_{c}$, $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ push the energy of system below the threshold of $\Lambda_{c}\Lambda_{c}$ by $22$ MeV. The corresponding system $\Lambda_{b}\Lambda_{b}$ has the similar properties as that of $\Lambda_{c}\Lambda_{c}$ system, and a bound state is also possible in $\Lambda_{b}\Lambda_{b}$ system.
0706.0399
Sandhya Choubey
Ram Lal Awasthi, Sandhya Choubey
Confusing Sterile Neutrinos with Deviation from Tribimaximal Mixing at Neutrino Telescopes
22 pages, version to appear in Phys. Rev. D
Phys.Rev.D76:113002,2007
10.1103/PhysRevD.76.113002
HRI-P-07-06-001
hep-ph astro-ph hep-ex
null
We expound the impact of extra sterile species on the ultra high energy neutrino fluxes in neutrino telescopes. We use three types of well-known flux ratios and compare the values of these flux ratios in presence of sterile neutrinos, with those predicted by deviation from the tribimaximal mixing scheme. We show that in the upcoming neutrino telescopes, its easy to confuse between the signature of sterile neutrinos with that of the deviation from tribimaximal mixing. We also show that if the measured flux ratios acquire a value well outside the range predicted by the standard scenario with three active neutrinos only, it might be possible to tell the presence of extra sterile neutrinos by observing ultra high energy neutrinos in future neutrino telescopes.
[ { "created": "Mon, 4 Jun 2007 09:16:32 GMT", "version": "v1" }, { "created": "Wed, 17 Oct 2007 15:44:12 GMT", "version": "v2" } ]
2008-11-26
[ [ "Awasthi", "Ram Lal", "" ], [ "Choubey", "Sandhya", "" ] ]
We expound the impact of extra sterile species on the ultra high energy neutrino fluxes in neutrino telescopes. We use three types of well-known flux ratios and compare the values of these flux ratios in presence of sterile neutrinos, with those predicted by deviation from the tribimaximal mixing scheme. We show that in the upcoming neutrino telescopes, its easy to confuse between the signature of sterile neutrinos with that of the deviation from tribimaximal mixing. We also show that if the measured flux ratios acquire a value well outside the range predicted by the standard scenario with three active neutrinos only, it might be possible to tell the presence of extra sterile neutrinos by observing ultra high energy neutrinos in future neutrino telescopes.
hep-ph/0209229
Felix Nagel
Markus Diehl, Otto Nachtmann and Felix Nagel
Triple gauge couplings in polarised e-e+ -> W-W+ and their measurement using optimal observables
56 pages, 20 figures
Eur.Phys.J.C27:375-397,2003
10.1140/epjc/s2002-01096-y
HD-THEP-02-34
hep-ph
null
The sensitivity of optimal integrated observables to electroweak triple gauge couplings is investigated for the process e-e+ -> W-W+ -> 4 fermions at future linear colliders. By a suitable reparameterisation of the couplings we achieve that all 28 coupling parameters have uncorrelated statistical errors and are naturally normalised for this process. Discrete symmetry properties simplify the analysis and allow checks on the stability of numerical results. We investigate the sensitivity to the couplings of the normalised event distribution and the additional constraints that can be obtained from the total rate. Particular emphasis is put on the gain in sensitivity one can achieve with longitudinal beam polarisation. We also point out questions that may best be settled with transversely polarised beams. In particular we find that with purely longitudinal polarisation one linear combination of coupling parameters is hardly measurable by means of the normalised event distribution.
[ { "created": "Thu, 19 Sep 2002 16:01:29 GMT", "version": "v1" } ]
2011-09-13
[ [ "Diehl", "Markus", "" ], [ "Nachtmann", "Otto", "" ], [ "Nagel", "Felix", "" ] ]
The sensitivity of optimal integrated observables to electroweak triple gauge couplings is investigated for the process e-e+ -> W-W+ -> 4 fermions at future linear colliders. By a suitable reparameterisation of the couplings we achieve that all 28 coupling parameters have uncorrelated statistical errors and are naturally normalised for this process. Discrete symmetry properties simplify the analysis and allow checks on the stability of numerical results. We investigate the sensitivity to the couplings of the normalised event distribution and the additional constraints that can be obtained from the total rate. Particular emphasis is put on the gain in sensitivity one can achieve with longitudinal beam polarisation. We also point out questions that may best be settled with transversely polarised beams. In particular we find that with purely longitudinal polarisation one linear combination of coupling parameters is hardly measurable by means of the normalised event distribution.
hep-ph/0208003
Lotfi Boubekeur
Lotfi Boubekeur (SISSA/ISAS Trieste & INFN Trieste)
Leptogenesis at Low Scale
LateX, 12 pages, axodraw figures
null
null
null
hep-ph
null
A typical problem of the leptogenesis scenario is the mismatch between the maximum reheat temperature implied by gravitino overproduction bound and the minimum temperature required to create thermally the lightest right-handed neutrino. We explore the possibility of baryogenesis via leptogenesis in the presence of low scale mass right-handed neutrino. In such a scenario, right-handed neutrinos are created thermally at low reheat temperatures without relying on non-perturbative production mechanisms. We focus on two specific realizations of the scenario, namely the out-of-equilibrium decay of right-handed neutrinos (Fukugita-Yanagida) and the leptogenesis via the $LH_u$ flat direction (Affleck-Dine). We find that in general, the two scenarios are able to produce the required baryon excess for a reasonable amount of CP violation.
[ { "created": "Thu, 1 Aug 2002 13:38:48 GMT", "version": "v1" } ]
2007-05-23
[ [ "Boubekeur", "Lotfi", "", "SISSA/ISAS Trieste & INFN Trieste" ] ]
A typical problem of the leptogenesis scenario is the mismatch between the maximum reheat temperature implied by gravitino overproduction bound and the minimum temperature required to create thermally the lightest right-handed neutrino. We explore the possibility of baryogenesis via leptogenesis in the presence of low scale mass right-handed neutrino. In such a scenario, right-handed neutrinos are created thermally at low reheat temperatures without relying on non-perturbative production mechanisms. We focus on two specific realizations of the scenario, namely the out-of-equilibrium decay of right-handed neutrinos (Fukugita-Yanagida) and the leptogenesis via the $LH_u$ flat direction (Affleck-Dine). We find that in general, the two scenarios are able to produce the required baryon excess for a reasonable amount of CP violation.
0805.1119
Qiang Zhao
Xiao-Hai Liu and Qiang Zhao
Search for a promising tetraquark candidate $X(ud\bar{s}\bar{s})$ in $pn\to \Lambda\Lambda X$
Revised version to appear on J. Phys. G. Additional discussions on the tetraquark production mechanisms are included
J.Phys.G36:015003,2009
10.1088/0954-3899/36/1/015003
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose to search for a tetraquark candidate $X(ud\bar{s}\bar{s})$ in $pn\to \Lambda\Lambda X(ud\bar{s}\bar{s})\to \Lambda\Lambda K^+K^0$ or $\Lambda\Lambda KK^*$. The existence of tetraquark state $X(ud\bar{s}\bar{s})$ with $J^P=0^+$, $1^-$ or $1^+$ was predicted in the literature based on specific diquark effective degrees of freedom inside hadrons. In order to understand the underlying dynamics for exotic hadrons, a search for the tetraquark $X(ud\bar{s}\bar{s})$ is strongly recommended. The proposed reaction involves two $\Lambda$ production, of which the narrow widths make it a great advantage in the analysis of the final state missing mass spectrum. We make an estimate of the production rate of $X(ud\bar{s}\bar{s})$ in an effective Lagrangian theory and find that for $J^P=1^-$ the sample events of $\sim 2200 \ nb^{-1}$ will be able to identify $X(ud\bar{s}\bar{s})$ with five standard deviations at a width of 10 MeV to $K^+K^0$ near threshold. For $J^P=1^+$ with a width of 20 MeV to $KK^*$, the sample events of $\sim 130 nb^{-1}$ will be needed. Large production cross sections are expected in a kinematic region beyond the threshold. We emphasize the advantage of low background in this transition channel, and in the meantime caution the large uncertainties in the present estimate due to lack of knowledge about the $X(ud\bar{s}\bar{s})$ state. Implications for its heavy-flavored partners $qq\bar{c}\bar{c}$ and $qq\bar{b}\bar{b}$ are briefly discussed.
[ { "created": "Thu, 8 May 2008 08:20:35 GMT", "version": "v1" }, { "created": "Thu, 4 Sep 2008 13:35:11 GMT", "version": "v2" }, { "created": "Fri, 3 Oct 2008 04:19:45 GMT", "version": "v3" } ]
2008-12-18
[ [ "Liu", "Xiao-Hai", "" ], [ "Zhao", "Qiang", "" ] ]
We propose to search for a tetraquark candidate $X(ud\bar{s}\bar{s})$ in $pn\to \Lambda\Lambda X(ud\bar{s}\bar{s})\to \Lambda\Lambda K^+K^0$ or $\Lambda\Lambda KK^*$. The existence of tetraquark state $X(ud\bar{s}\bar{s})$ with $J^P=0^+$, $1^-$ or $1^+$ was predicted in the literature based on specific diquark effective degrees of freedom inside hadrons. In order to understand the underlying dynamics for exotic hadrons, a search for the tetraquark $X(ud\bar{s}\bar{s})$ is strongly recommended. The proposed reaction involves two $\Lambda$ production, of which the narrow widths make it a great advantage in the analysis of the final state missing mass spectrum. We make an estimate of the production rate of $X(ud\bar{s}\bar{s})$ in an effective Lagrangian theory and find that for $J^P=1^-$ the sample events of $\sim 2200 \ nb^{-1}$ will be able to identify $X(ud\bar{s}\bar{s})$ with five standard deviations at a width of 10 MeV to $K^+K^0$ near threshold. For $J^P=1^+$ with a width of 20 MeV to $KK^*$, the sample events of $\sim 130 nb^{-1}$ will be needed. Large production cross sections are expected in a kinematic region beyond the threshold. We emphasize the advantage of low background in this transition channel, and in the meantime caution the large uncertainties in the present estimate due to lack of knowledge about the $X(ud\bar{s}\bar{s})$ state. Implications for its heavy-flavored partners $qq\bar{c}\bar{c}$ and $qq\bar{b}\bar{b}$ are briefly discussed.
hep-ph/0012324
Muneyuki Ishida
Kunio Takamatsu (CROSS, Japan)
sigma and kappa in Scattering Processes and New pi0 pi0 Phase Shift Data
proc. of ``Possible Existence of sigma-Meson and Its Implication to Hadron Physics," YITP, Kyoto, June 12--14, 2000. 6 pages, uses ptptex.sty
Prog.Theor.Phys. 102 (2001) E52-E57
null
null
hep-ph
null
The evidences for sigma(600) and kappa(900) observed in our analyses on the pi pi and K pi scattering phase shift data are described, briefly. The analysis have been performed by the interfering amplitude method, which satisfies the unitarity requirement, using physically meaningful parameters. The introduction of the negative phase shifts (repulsive force) are essential in the analysis. New data for the pi0 pi0 scattering amplitudes and the I=0 S wave phase shifts are presented. The data have been obtained in the pi-p charge exchange reaction, pi- p --> pi0 pi0 n at 9 GeV by the E135 experiment at the KEK PS. The amplitude analysis are performed. The behavior of the I=0 S wave phase shifts below KKbar threshold are consistent with those of the pi+ pi-, so called, standard data and those of the down-flat solution of the CERN-Cracow-Munich polarization data. The analysis of the pi0 pi0 phase shift data observes sigma(600) with the B-W parameters, M_sigma =588 +- 12 MeV and Gamma_sigma =281 +- 25 MeV, which are in good agreement with those in our analysis on the pi+ pi- data.
[ { "created": "Sat, 23 Dec 2000 13:57:51 GMT", "version": "v1" } ]
2007-05-23
[ [ "Takamatsu", "Kunio", "", "CROSS, Japan" ] ]
The evidences for sigma(600) and kappa(900) observed in our analyses on the pi pi and K pi scattering phase shift data are described, briefly. The analysis have been performed by the interfering amplitude method, which satisfies the unitarity requirement, using physically meaningful parameters. The introduction of the negative phase shifts (repulsive force) are essential in the analysis. New data for the pi0 pi0 scattering amplitudes and the I=0 S wave phase shifts are presented. The data have been obtained in the pi-p charge exchange reaction, pi- p --> pi0 pi0 n at 9 GeV by the E135 experiment at the KEK PS. The amplitude analysis are performed. The behavior of the I=0 S wave phase shifts below KKbar threshold are consistent with those of the pi+ pi-, so called, standard data and those of the down-flat solution of the CERN-Cracow-Munich polarization data. The analysis of the pi0 pi0 phase shift data observes sigma(600) with the B-W parameters, M_sigma =588 +- 12 MeV and Gamma_sigma =281 +- 25 MeV, which are in good agreement with those in our analysis on the pi+ pi- data.
1305.2627
Cheuk-Yin Wong
Cheuk-Yin Wong and Grzegorz Wilk
Tsallis Fits to pT Spectra and Multiple Hard Scattering in pp Collisions at the LHC
19 pages, 8 figures
Phys. Rev. D 87, 114007 (2013)
10.1103/PhysRevD.87.114007
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pT^n at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n~4-5.
[ { "created": "Sun, 12 May 2013 20:01:33 GMT", "version": "v1" }, { "created": "Fri, 21 Jun 2013 17:33:58 GMT", "version": "v2" } ]
2013-06-24
[ [ "Wong", "Cheuk-Yin", "" ], [ "Wilk", "Grzegorz", "" ] ]
Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pT^n at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n~4-5.
hep-ph/0105268
Adrian Dumitru
Adrian Dumitru (Columbia Univ.) and Larry McLerran (BNL)
How Protons Shatter Colored Glass
9 pages, RevTex, 3 Figures; some typos corrected, the scaling of <kt>^2 with dN/dy is derived
Nucl.Phys.A700:492-508,2002
10.1016/S0375-9474(01)01301-X
CU-TP-1018, BNL-NT-01/10
hep-ph nucl-th
null
We consider the implications of the Color Glass Condensate for the central region of p+A collisions. We compute the k_t distribution of radiated gluons and their rapidity distribution dN/dy analytically, both in the perturbative regime and in the region between the two saturation momenta. We find an analytic expression for the number of produced gluons which is valid when the saturation momentum of the proton is much less than that of the nucleus. We discuss the scaling of the produced multiplicity with A. We show that the slope of the rapidity density dN/dy provides an experimental measure for the renormalization-group evolution of the color charge density of the Color Glass Condensate (CGC). We also argue that these results are easily generalized to collisions of nuclei of different A at central rapidity, or with the same A but at a rapidity far from the central region.
[ { "created": "Fri, 25 May 2001 18:46:44 GMT", "version": "v1" }, { "created": "Thu, 13 Sep 2001 14:41:16 GMT", "version": "v2" } ]
2010-04-06
[ [ "Dumitru", "Adrian", "", "Columbia Univ." ], [ "McLerran", "Larry", "", "BNL" ] ]
We consider the implications of the Color Glass Condensate for the central region of p+A collisions. We compute the k_t distribution of radiated gluons and their rapidity distribution dN/dy analytically, both in the perturbative regime and in the region between the two saturation momenta. We find an analytic expression for the number of produced gluons which is valid when the saturation momentum of the proton is much less than that of the nucleus. We discuss the scaling of the produced multiplicity with A. We show that the slope of the rapidity density dN/dy provides an experimental measure for the renormalization-group evolution of the color charge density of the Color Glass Condensate (CGC). We also argue that these results are easily generalized to collisions of nuclei of different A at central rapidity, or with the same A but at a rapidity far from the central region.
1012.0703
Bohdan Grzadkowski
Bohdan Grzadkowski, Per Osland
Natural Two-Higgs-Doublet Model
2 figures, submitted to Fortschritte der Physik, presented at the 10th Hellenic School on Elementary Particle Physics and Gravity, Corfu 2010
null
10.1002/prop.201000098
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the Two-Higgs-Doublet Model (2HDM) constrained by the two-loop-order requirement of cancellation of quadratic divergences is consistent with the existing experimental constraints. The model allows to ameliorate the little hierarchy problem by suppressing the quadratic corrections to scalar masses and lifting the mass of the lightest Higgs boson. A strong source of CP violation emerges from the scalar potential. The cutoff originating from the naturality arguments is shifted from 0.6 TeV in the Standard Model to >6 TeV in the 2HDM, depending on the mass of the lightest scalar.
[ { "created": "Fri, 3 Dec 2010 11:15:02 GMT", "version": "v1" }, { "created": "Thu, 9 Dec 2010 11:44:41 GMT", "version": "v2" } ]
2015-05-20
[ [ "Grzadkowski", "Bohdan", "" ], [ "Osland", "Per", "" ] ]
We show that the Two-Higgs-Doublet Model (2HDM) constrained by the two-loop-order requirement of cancellation of quadratic divergences is consistent with the existing experimental constraints. The model allows to ameliorate the little hierarchy problem by suppressing the quadratic corrections to scalar masses and lifting the mass of the lightest Higgs boson. A strong source of CP violation emerges from the scalar potential. The cutoff originating from the naturality arguments is shifted from 0.6 TeV in the Standard Model to >6 TeV in the 2HDM, depending on the mass of the lightest scalar.
2306.03388
Hai-Bing Fu
Hai-Jiang Tian, Xuan Luo, Hai-Bing Fu
Further study on the production of P-wave doubly heavy baryons from Z-boson decays
11 pages, 4 figures, matches published version in PLB
Physics Letters B 847 (2023) 138302
10.1016/j.physletb.2023.138302
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In this paper, we carried out a systematic investigation for the excited doubly heavy baryons production in $Z$-boson decays within the NRQCD factorization approach. Our investigation accounts for all the $P$-wave intermediate diquark states, {\it i.e.} $\langle cc\rangle[^1P_1]_{\bar 3}$, $\langle cc\rangle[^3P_J]_{6}$, $\langle bc\rangle[^1P_1]_{\bar 3/6}$, $\langle bc\rangle[^3P_J]_{\bar 3/6}$, $\langle bb\rangle[^1P_1]_{\bar 3}$, and $\langle bb\rangle[^3P_J]_{6}$ with $J = (0, 1, 2)$. The results show that contributions from all diquark states in $P$-wave were $7\%$, $8\%$, and $3\%$ in comparing with $S$-wave for the production of $\Xi_{cc}$, $\Xi_{bc}$ and $\Xi_{bb}$ via $Z$-boson decay, respectively. Based on these results, we predicted about $0.539\times 10^3(10^6)$ events for $\Xi_{cc}$, $1.827\times 10^3(10^6)$ events for $\Xi_{bc}$, and $0.036\times 10^3(10^6)$ events for $\Xi_{bb}$ can be produced annually at the LHC (CEPC). Additionally, we plot the differential decay widths of $\Xi_{cc}$, $\Xi_{bc}$ and $\Xi_{bb}$ as a function of the invariant mass $s_{23}$ and energy function $z$ distributions, and analyze the theoretical uncertainties in decay width arising from the mass parameters of heavy quark.
[ { "created": "Tue, 6 Jun 2023 04:04:34 GMT", "version": "v1" }, { "created": "Fri, 17 Nov 2023 16:10:26 GMT", "version": "v2" } ]
2023-11-20
[ [ "Tian", "Hai-Jiang", "" ], [ "Luo", "Xuan", "" ], [ "Fu", "Hai-Bing", "" ] ]
In this paper, we carried out a systematic investigation for the excited doubly heavy baryons production in $Z$-boson decays within the NRQCD factorization approach. Our investigation accounts for all the $P$-wave intermediate diquark states, {\it i.e.} $\langle cc\rangle[^1P_1]_{\bar 3}$, $\langle cc\rangle[^3P_J]_{6}$, $\langle bc\rangle[^1P_1]_{\bar 3/6}$, $\langle bc\rangle[^3P_J]_{\bar 3/6}$, $\langle bb\rangle[^1P_1]_{\bar 3}$, and $\langle bb\rangle[^3P_J]_{6}$ with $J = (0, 1, 2)$. The results show that contributions from all diquark states in $P$-wave were $7\%$, $8\%$, and $3\%$ in comparing with $S$-wave for the production of $\Xi_{cc}$, $\Xi_{bc}$ and $\Xi_{bb}$ via $Z$-boson decay, respectively. Based on these results, we predicted about $0.539\times 10^3(10^6)$ events for $\Xi_{cc}$, $1.827\times 10^3(10^6)$ events for $\Xi_{bc}$, and $0.036\times 10^3(10^6)$ events for $\Xi_{bb}$ can be produced annually at the LHC (CEPC). Additionally, we plot the differential decay widths of $\Xi_{cc}$, $\Xi_{bc}$ and $\Xi_{bb}$ as a function of the invariant mass $s_{23}$ and energy function $z$ distributions, and analyze the theoretical uncertainties in decay width arising from the mass parameters of heavy quark.
hep-ph/0604184
Elena G. Ferreiro
A. Capella and E. G. Ferreiro
Elliptic Flow in a Final State Interaction Model
4 pages, 6 figures, proceedings of XLIst Rencontres de Moriond: QCD and Hadronic Interactions at high energy
null
null
null
hep-ph
null
We propose a final state interaction model to describe the fixed $p_T$ suppression of the yield of particles at all values of $p_T$. We make an extension of the model to the motion in the transverse plane which introduces a dependence of the suppression on the azimuthal angle $\theta_R$. We obtain values of the elliptic flow $v_{2}$ close to the experimental ones for all values of $p_T$.
[ { "created": "Fri, 21 Apr 2006 17:28:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Capella", "A.", "" ], [ "Ferreiro", "E. G.", "" ] ]
We propose a final state interaction model to describe the fixed $p_T$ suppression of the yield of particles at all values of $p_T$. We make an extension of the model to the motion in the transverse plane which introduces a dependence of the suppression on the azimuthal angle $\theta_R$. We obtain values of the elliptic flow $v_{2}$ close to the experimental ones for all values of $p_T$.
hep-ph/0011384
Carlo Oleari
Carlo Oleari
The tensor reduction and master integrals of the two-loop massless crossed box
3 pages, 1 figure. Talk given at ACAT2000, Fermilab, IL, 16-20 October, 2000. To be published in "Advanced Computing and Analysis Techniques in Physics Research", AIP
null
10.1063/1.1405302
null
hep-ph
null
We briefly discuss an algorithm for the tensor reduction of the two-loop massless crossed boxes, with light-like external legs, and the computation of the relative master integrals.
[ { "created": "Thu, 30 Nov 2000 07:43:13 GMT", "version": "v1" } ]
2009-10-31
[ [ "Oleari", "Carlo", "" ] ]
We briefly discuss an algorithm for the tensor reduction of the two-loop massless crossed boxes, with light-like external legs, and the computation of the relative master integrals.
2202.10509
Alfredo Glioti
Siyu Chen, Alfredo Glioti, Riccardo Rattazzi, Lorenzo Ricci, Andrea Wulzer
Learning from Radiation at a Very High Energy Lepton Collider
48 pages, 17 figures
null
10.1007/JHEP05(2022)180
null
hep-ph hep-ex hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the potential of lepton collisions with about $10\text{ TeV}$ center of mass energy to probe Electroweak, Higgs and Top short-distance physics at the $100\text{ TeV}$ scale, pointing out the interplay with the long-distance ($100\text{ GeV}$) phenomenon of Electroweak radiation. On one hand, we find that sufficiently accurate theoretical predictions require the resummed inclusion of radiation effects, which we perform at the double logarithmic order. On the other hand, we notice that short-distance physics does influence the emission of Electroweak radiation. Therefore the investigation of the radiation pattern can enhance the sensitivity to new short-distance physical laws. We illustrate these aspects by studying Effective Field Theory contact interactions in di-fermion and di-boson production, and comparing cross-section measurements that require or that exclude the emission of massive Electroweak bosons. The combination of the two types of measurements is found to enhance the sensitivity to the new interactions. Based on these results, we perform sensitivity projections to Higgs and Top Compositeness and to minimal $Z'$ new physics scenarios at future muon colliders.
[ { "created": "Mon, 21 Feb 2022 19:45:50 GMT", "version": "v1" } ]
2022-06-15
[ [ "Chen", "Siyu", "" ], [ "Glioti", "Alfredo", "" ], [ "Rattazzi", "Riccardo", "" ], [ "Ricci", "Lorenzo", "" ], [ "Wulzer", "Andrea", "" ] ]
We study the potential of lepton collisions with about $10\text{ TeV}$ center of mass energy to probe Electroweak, Higgs and Top short-distance physics at the $100\text{ TeV}$ scale, pointing out the interplay with the long-distance ($100\text{ GeV}$) phenomenon of Electroweak radiation. On one hand, we find that sufficiently accurate theoretical predictions require the resummed inclusion of radiation effects, which we perform at the double logarithmic order. On the other hand, we notice that short-distance physics does influence the emission of Electroweak radiation. Therefore the investigation of the radiation pattern can enhance the sensitivity to new short-distance physical laws. We illustrate these aspects by studying Effective Field Theory contact interactions in di-fermion and di-boson production, and comparing cross-section measurements that require or that exclude the emission of massive Electroweak bosons. The combination of the two types of measurements is found to enhance the sensitivity to the new interactions. Based on these results, we perform sensitivity projections to Higgs and Top Compositeness and to minimal $Z'$ new physics scenarios at future muon colliders.
0907.2006
Yusuke Shimizu
Hajime Ishimori, Tatsuo Kobayashi, Hiroshi Okada, Yusuke Shimizu, Morimitsu Tanimoto
Delta(54) Flavor Model for Leptons and Sleptons
22 pages, 4 figures, with minor modifications, figures are revised and discussions are added
JHEP 0912:054,2009
10.1088/1126-6708/2009/12/054
KUNS-2214
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied $\Delta(54)\times Z_2$ flavor model for leptons and sleptons. The tri-bimaximal mixing can be reproduced for arbitrary neutrino masses if vacuum alignments of scalar fields are guaranteed. The deviation from the tri-bimaximal mixing of leptons is predicted. The predicted upper bound for $\sin\theta_{13}$ is 0.06. The magnitude of $\sin\theta_{23}$ could be deviated from the maximal mixing considerably, but $\sin\theta_{12}$ is hardly deviated from the tri-maximal mixing. We have also studied SUSY breaking terms in the slepton sector. Three families of left-handed and right-handed slepton masses are degenerate. Even although flavor symmetry breaking effects are taken into account, our model leads to smaller values of flavor changing neutral currents than the present experimental bounds.
[ { "created": "Mon, 13 Jul 2009 04:16:37 GMT", "version": "v1" }, { "created": "Wed, 22 Jul 2009 07:57:58 GMT", "version": "v2" }, { "created": "Mon, 19 Oct 2009 08:38:37 GMT", "version": "v3" } ]
2010-01-15
[ [ "Ishimori", "Hajime", "" ], [ "Kobayashi", "Tatsuo", "" ], [ "Okada", "Hiroshi", "" ], [ "Shimizu", "Yusuke", "" ], [ "Tanimoto", "Morimitsu", "" ] ]
We have studied $\Delta(54)\times Z_2$ flavor model for leptons and sleptons. The tri-bimaximal mixing can be reproduced for arbitrary neutrino masses if vacuum alignments of scalar fields are guaranteed. The deviation from the tri-bimaximal mixing of leptons is predicted. The predicted upper bound for $\sin\theta_{13}$ is 0.06. The magnitude of $\sin\theta_{23}$ could be deviated from the maximal mixing considerably, but $\sin\theta_{12}$ is hardly deviated from the tri-maximal mixing. We have also studied SUSY breaking terms in the slepton sector. Three families of left-handed and right-handed slepton masses are degenerate. Even although flavor symmetry breaking effects are taken into account, our model leads to smaller values of flavor changing neutral currents than the present experimental bounds.
1909.00370
Jose Antonio Oller
J.A. Oller
Coupled-channel approach in hadron-hadron scattering
104 pages, 9 figures. Invited review article for Prog. Part. Nucl. Phys
null
10.1016/j.ppnp.2019.103728
null
hep-ph cond-mat.quant-gas nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Coupled-channel dynamics for scattering and production processes in partial-wave amplitudes is discussed from a perspective that emphasizes unitarity and analyticity. We elaborate on several methods that have driven to important results in hadron physics, either by themselves or in conjunction with effective field theory. We also develop and compare with the use of the Lippmann-Schwinger equation in near-threshold scattering. The final(initial)-state interactions are discussed in detail for the elastic and coupled-channel case. Emphasis has been put in the derivation and discussion of the methods presented, with some applications examined as important examples of their usage.
[ { "created": "Sun, 1 Sep 2019 10:07:40 GMT", "version": "v1" } ]
2020-01-08
[ [ "Oller", "J. A.", "" ] ]
Coupled-channel dynamics for scattering and production processes in partial-wave amplitudes is discussed from a perspective that emphasizes unitarity and analyticity. We elaborate on several methods that have driven to important results in hadron physics, either by themselves or in conjunction with effective field theory. We also develop and compare with the use of the Lippmann-Schwinger equation in near-threshold scattering. The final(initial)-state interactions are discussed in detail for the elastic and coupled-channel case. Emphasis has been put in the derivation and discussion of the methods presented, with some applications examined as important examples of their usage.
2310.00586
Kang Sin Choi
Kang-Sin Choi
On the Observables of Renormalizable Interactions
9 pages, 1 figure, published version
null
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We reconsider the renormalization of scalar mass and point out that the quantum correction to the physical observable, as opposed to the bare parameter, of a renormalizable operator, is technically insensitive to ultraviolet physics and independent of the regularization scheme. It is expressed as the difference in the same quantities at different energy scales, maintaining the same asymptotics. Thus, any sensible regularization cancels out the divergences, including the quadratic ones, and yields the same finite corrections. To this end, we first show that the vacuum polarization of quantum electrodynamics is independent of the regularization scheme and a gauge-dependent quadratic divergence is canceled in the observable. We then calculate the quantum correction to the Higgs mass squared by the top-quark loop. It is again finite and regularization-scheme independent. For large external momentum, the correction of the pole mass-squared is dominated by power running, resulting in an order of 0.1 percent correction. In particular, the effect of heavy fields on the scalar mass correction is suppressed.
[ { "created": "Sun, 1 Oct 2023 06:11:21 GMT", "version": "v1" }, { "created": "Wed, 4 Oct 2023 11:43:38 GMT", "version": "v2" }, { "created": "Fri, 9 Feb 2024 05:55:49 GMT", "version": "v3" } ]
2024-02-12
[ [ "Choi", "Kang-Sin", "" ] ]
We reconsider the renormalization of scalar mass and point out that the quantum correction to the physical observable, as opposed to the bare parameter, of a renormalizable operator, is technically insensitive to ultraviolet physics and independent of the regularization scheme. It is expressed as the difference in the same quantities at different energy scales, maintaining the same asymptotics. Thus, any sensible regularization cancels out the divergences, including the quadratic ones, and yields the same finite corrections. To this end, we first show that the vacuum polarization of quantum electrodynamics is independent of the regularization scheme and a gauge-dependent quadratic divergence is canceled in the observable. We then calculate the quantum correction to the Higgs mass squared by the top-quark loop. It is again finite and regularization-scheme independent. For large external momentum, the correction of the pole mass-squared is dominated by power running, resulting in an order of 0.1 percent correction. In particular, the effect of heavy fields on the scalar mass correction is suppressed.
0907.3737
Adam Martin
Kenneth Lane, Adam Martin
An Effective Lagrangian for Low-Scale Technicolor
Updated introduction, to appear in Phys. Rev. D
null
10.1103/PhysRevD.80.115001
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an effective Lagrangian for low-scale technicolor. It describes the interactions at energies near the mass of the lowest-lying bound states of the lightest technifermion doublet -- the spin-one $\rho_T,\omega_T, a_T, f_T$ and the corresponding technipions $\pi_T$. This Lagrangian is intended to put on firmer ground the technicolor straw-man phenomenology used for collider searches of low-scale technicolor. The technivectors are described using the hidden local symmetry (HLS) formalism of Bando et al. The Lagrangian is based on $SU(2)\otimes U(1)\otimes U(2)_L \otimes U(2)_R$, where $SU(2)\otimes U(1)$ is the electroweak gauge group and $U(2)_L \otimes U(2)_R$ is the HLS gauge group. Special attention is paid to the higher-derivative standard HLS and Wess-Zumino-Witten interactions needed to describe radiative and other decays of the $a_T$ and $\rho_T/\omega_T$, respectively.
[ { "created": "Tue, 21 Jul 2009 20:08:48 GMT", "version": "v1" }, { "created": "Mon, 19 Oct 2009 18:57:14 GMT", "version": "v2" } ]
2013-05-29
[ [ "Lane", "Kenneth", "" ], [ "Martin", "Adam", "" ] ]
We present an effective Lagrangian for low-scale technicolor. It describes the interactions at energies near the mass of the lowest-lying bound states of the lightest technifermion doublet -- the spin-one $\rho_T,\omega_T, a_T, f_T$ and the corresponding technipions $\pi_T$. This Lagrangian is intended to put on firmer ground the technicolor straw-man phenomenology used for collider searches of low-scale technicolor. The technivectors are described using the hidden local symmetry (HLS) formalism of Bando et al. The Lagrangian is based on $SU(2)\otimes U(1)\otimes U(2)_L \otimes U(2)_R$, where $SU(2)\otimes U(1)$ is the electroweak gauge group and $U(2)_L \otimes U(2)_R$ is the HLS gauge group. Special attention is paid to the higher-derivative standard HLS and Wess-Zumino-Witten interactions needed to describe radiative and other decays of the $a_T$ and $\rho_T/\omega_T$, respectively.
0907.4110
Prashant Saraswat
Daniele S. M. Alves, Martin Jankowiak, Prashant Saraswat
Experimental constraints on the free fall acceleration of antimatter
7 pages (two columns), 2 figures
null
null
SU-ITP-09/36
hep-ph gr-qc hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In light of recent experimental proposals to measure the free fall acceleration of antihydrogen in the earth's gravitational field, we investigate the bounds that existing experiments place on any asymmetry between the free fall of matter and antimatter. We conclude that existing experiments constrain any such asymmetry to be less than about 10^-7. First we consider contributions to the inertial masses of atoms that encode the presence of antimatter and use precision Eotvos experiments to establish the level at which they satisfy the equivalence principle. In particular we focus on vacuum polarization effects and the antiquark content of nucleons. Second we consider a class of theories that contain long range scalar and vector forces that cancel with one another to some high precision. By construction such theories would be able to evade detection in Eotvos experiments that utilize matter while still allowing for a signal in antimatter experiments. Even taking such cancellation for granted, however, we show that the radiative damping of binary pulsar systems constrains these forces to be significantly weaker than gravity. Furthermore we show that there are limits to the accuracy with which such cancellation can be arranged: first by determining the precision to which scalar charges can track vector charges in the best candidate theories; and, second, by showing that the different velocity dependence of scalar and vector forces necessarily introduces non-cancellation at a quantifiable level.
[ { "created": "Thu, 23 Jul 2009 19:11:41 GMT", "version": "v1" } ]
2009-07-24
[ [ "Alves", "Daniele S. M.", "" ], [ "Jankowiak", "Martin", "" ], [ "Saraswat", "Prashant", "" ] ]
In light of recent experimental proposals to measure the free fall acceleration of antihydrogen in the earth's gravitational field, we investigate the bounds that existing experiments place on any asymmetry between the free fall of matter and antimatter. We conclude that existing experiments constrain any such asymmetry to be less than about 10^-7. First we consider contributions to the inertial masses of atoms that encode the presence of antimatter and use precision Eotvos experiments to establish the level at which they satisfy the equivalence principle. In particular we focus on vacuum polarization effects and the antiquark content of nucleons. Second we consider a class of theories that contain long range scalar and vector forces that cancel with one another to some high precision. By construction such theories would be able to evade detection in Eotvos experiments that utilize matter while still allowing for a signal in antimatter experiments. Even taking such cancellation for granted, however, we show that the radiative damping of binary pulsar systems constrains these forces to be significantly weaker than gravity. Furthermore we show that there are limits to the accuracy with which such cancellation can be arranged: first by determining the precision to which scalar charges can track vector charges in the best candidate theories; and, second, by showing that the different velocity dependence of scalar and vector forces necessarily introduces non-cancellation at a quantifiable level.
hep-ph/9710549
null
A. Abada, O. Azi and A. Tadji
Damping rate for transverse gluons with finite soft momentum in hot QCD
13 pages, TeX file. References updated, misprints corrected and minor changes
null
null
ENSK-ph/97-02
hep-ph
null
We calculate the damping rate for transverse gluons with {\nineti finite} soft momentum to leading order in perturbative hot QCD. The internal momenta of the one-loop contributing diagrams are soft. This means we have to use effective vertices and propagators which incorporate the so-called hard thermal loops. We expand the damping rate in powers of the incoming momentum and argue that the series ought to converge within a finite radius of convergence. We contrast such a behavior with the one obtained from a previous calculation that produced a logarithmic behavior, a calculation based on letting the gluon momentum come from the hard limit down towards the interior of the soft region. This difference in behavior may point to interesting physics around some `critical' region.
[ { "created": "Thu, 30 Oct 1997 21:53:16 GMT", "version": "v1" }, { "created": "Tue, 25 Nov 1997 21:48:08 GMT", "version": "v2" } ]
2007-05-23
[ [ "Abada", "A.", "" ], [ "Azi", "O.", "" ], [ "Tadji", "A.", "" ] ]
We calculate the damping rate for transverse gluons with {\nineti finite} soft momentum to leading order in perturbative hot QCD. The internal momenta of the one-loop contributing diagrams are soft. This means we have to use effective vertices and propagators which incorporate the so-called hard thermal loops. We expand the damping rate in powers of the incoming momentum and argue that the series ought to converge within a finite radius of convergence. We contrast such a behavior with the one obtained from a previous calculation that produced a logarithmic behavior, a calculation based on letting the gluon momentum come from the hard limit down towards the interior of the soft region. This difference in behavior may point to interesting physics around some `critical' region.
0807.2329
Dremin
I.M. Dremin
In-medium QCD and Cherenkov gluons vs Mach waves at LHC
6 p., no figures. Talk at the HERA-LHC workshop, 28 May 2008, CERN
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes the shock wave induced by emission of Cherenkov gluons. Specific effects at LHC energies are described and compared with Mach wave predictions.
[ { "created": "Tue, 15 Jul 2008 10:06:47 GMT", "version": "v1" } ]
2008-07-21
[ [ "Dremin", "I. M.", "" ] ]
The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes the shock wave induced by emission of Cherenkov gluons. Specific effects at LHC energies are described and compared with Mach wave predictions.
hep-ph/0701141
Valery Zamiralov
E.N.Dubovik, V.S.Zamiralov, S.N.Lepshokov
Weak radiative hyperon decays in quark model
12 pages, 5 tables, 5 figures
AIPConf.Proc.964:71-76,2007
10.1063/1.2823883
null
hep-ph
null
Weak radiative hyperon decays are considered in the framework of a quark model. The phenomenological model includes 1-quark transitions with the effective $sd\gamma$-vertex and 2-quark ones with the W-exchange $s+u\to u+d+\gamma$ and turns out to describe well the data and gives predictions for asymmetry of the decays $\Lambda\to n+\gamma$ and $\Xi^-\to \Sigma^- +\gamma$.
[ { "created": "Thu, 18 Jan 2007 11:36:05 GMT", "version": "v1" } ]
2008-11-26
[ [ "Dubovik", "E. N.", "" ], [ "Zamiralov", "V. S.", "" ], [ "Lepshokov", "S. N.", "" ] ]
Weak radiative hyperon decays are considered in the framework of a quark model. The phenomenological model includes 1-quark transitions with the effective $sd\gamma$-vertex and 2-quark ones with the W-exchange $s+u\to u+d+\gamma$ and turns out to describe well the data and gives predictions for asymmetry of the decays $\Lambda\to n+\gamma$ and $\Xi^-\to \Sigma^- +\gamma$.
hep-ph/9610349
Thorsten Ohl
Thorsten Ohl (TH Darmstadt)
Electroweak Event Generators for LEP2 and the Linear Collider
18 pages, LaTeX, to appear in the proceedings of CRAD'96, Third International Symposium on Radiative Corrections, Cracow, August 1-5, 1996
Acta Phys.Polon.B28:847-862,1997
null
IKDA 96/21
hep-ph
null
I discuss the state of the art and outline direction for research in event generation for electroweak physics at LEP2 and e+e- Linear Colliders.
[ { "created": "Mon, 14 Oct 1996 12:07:01 GMT", "version": "v1" } ]
2011-04-15
[ [ "Ohl", "Thorsten", "", "TH Darmstadt" ] ]
I discuss the state of the art and outline direction for research in event generation for electroweak physics at LEP2 and e+e- Linear Colliders.
1704.08937
Oleg Lebedev
Oleg Lebedev
Moriond QCD 2017: theoretical summary
9 pages, 5 figures; to appear in the proceedings of Moriond QCD 2017
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I summarize the highlights of the theory talks at the 52nd Rencontres de Moriond: QCD and high energy interactions.
[ { "created": "Fri, 28 Apr 2017 13:56:57 GMT", "version": "v1" }, { "created": "Wed, 10 May 2017 12:42:28 GMT", "version": "v2" } ]
2017-05-11
[ [ "Lebedev", "Oleg", "" ] ]
I summarize the highlights of the theory talks at the 52nd Rencontres de Moriond: QCD and high energy interactions.
hep-ph/9404352
null
Keith A. Olive
Big Bang Baryogenesis
36 pages, LaTeX, UMN-TH-1249, Lectures given at the 33rd International Winter School on Nuclear and Particle Physics, ``Matter Under Extreme Conditions", Feb. 27 - March 5 1994, Schladming Austria
null
10.1007/3-540-58689-X_40
null
hep-ph astro-ph
null
An overview of baryogenesis in the early Universe is presented. The standard big bang model including big bang nucleosynthesis and inflation is breifly reviewed. Three basic models for baryogenesis will be developed: The ``standard" out-of-equilibrium decay model; the decay of scalar consensates along flat directions in supersymmetric models; and lepto-baryogenesis, which is the conversion of a lepton asymmetry into a baryon asymmetry via non-perturbative electroweak interactions.
[ { "created": "Thu, 28 Apr 1994 17:10:25 GMT", "version": "v1" } ]
2015-06-25
[ [ "Olive", "Keith A.", "" ] ]
An overview of baryogenesis in the early Universe is presented. The standard big bang model including big bang nucleosynthesis and inflation is breifly reviewed. Three basic models for baryogenesis will be developed: The ``standard" out-of-equilibrium decay model; the decay of scalar consensates along flat directions in supersymmetric models; and lepto-baryogenesis, which is the conversion of a lepton asymmetry into a baryon asymmetry via non-perturbative electroweak interactions.
hep-ph/9602288
Paolo Nason
P. Nason, B.R. Webber, D.Ward, D. Lanske, L.A. del Pozo, F. Fabbri, B. Poli, G.Cowan, C.Padilla, M. Seymour, F. Hautmann, Yu.L. Dokshitzer and V.A. Khoze
QCD
44 pages, Latex, epsfig, 18 figures, to appear on the Report of the Workshop on Physics at LEP2, CERN 96-01, vol. 1, 1996
null
null
null
hep-ph
null
We discuss QCD studies that will be possible at LEP2. We examine both experimental and theoretical aspects of jets, fragmentation functions, multiplicities and particle spectra.
[ { "created": "Tue, 13 Feb 1996 13:02:22 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nason", "P.", "" ], [ "Webber", "B. R.", "" ], [ "Ward", "D.", "" ], [ "Lanske", "D.", "" ], [ "del Pozo", "L. A.", "" ], [ "Fabbri", "F.", "" ], [ "Poli", "B.", "" ], [ "Cowan", "G.", "" ], [ "Padilla", "C.", "" ], [ "Seymour", "M.", "" ], [ "Hautmann", "F.", "" ], [ "Dokshitzer", "Yu. L.", "" ], [ "Khoze", "V. A.", "" ] ]
We discuss QCD studies that will be possible at LEP2. We examine both experimental and theoretical aspects of jets, fragmentation functions, multiplicities and particle spectra.
2009.00301
Ivan Truten
I.V. Truten, A.Yu. Korchin
Energy and angular distributions of the bottom quark in the electron-positron annihilation $e^+e^-\to b \, W^+ \, \bar{t}$
16 pages, 7 figures, ws-ijmpa style; v3: Appendix A with discussion of gauge invariance and a few references added, published version
Int. J. Mod. Phys. A 36, No. 02, 2150013 (2021)
10.1142/S0217751X21500135
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The distributions of the bottom quark in the process $e^+ e^- \to t \, \bar{t} \to b \, W^+ \, \bar{t}$ are considered at the $e^+ e^-$ energy corresponding to the first construction stage of the Compact Linear Collider. The cross sections of $e^+ e^- \to b \ldots$, as functions of the $b$-quark energy and angle with respect to the direction of the electron beam, are derived and calculated. The effects of physics beyond the Standard Model are included via the modified $\gamma t \bar{t}$ and $Z t \bar{t}$ couplings which naturally appear in effective field theories. In addition to the cross sections, the energy and angular asymmetries are calculated. The dependence of these observables on the $e^+ e^-$ energy is calculated, and features of this dependence are investigated.
[ { "created": "Tue, 1 Sep 2020 09:12:19 GMT", "version": "v1" }, { "created": "Sun, 6 Sep 2020 11:58:02 GMT", "version": "v2" }, { "created": "Wed, 24 Feb 2021 16:02:20 GMT", "version": "v3" } ]
2021-02-25
[ [ "Truten", "I. V.", "" ], [ "Korchin", "A. Yu.", "" ] ]
The distributions of the bottom quark in the process $e^+ e^- \to t \, \bar{t} \to b \, W^+ \, \bar{t}$ are considered at the $e^+ e^-$ energy corresponding to the first construction stage of the Compact Linear Collider. The cross sections of $e^+ e^- \to b \ldots$, as functions of the $b$-quark energy and angle with respect to the direction of the electron beam, are derived and calculated. The effects of physics beyond the Standard Model are included via the modified $\gamma t \bar{t}$ and $Z t \bar{t}$ couplings which naturally appear in effective field theories. In addition to the cross sections, the energy and angular asymmetries are calculated. The dependence of these observables on the $e^+ e^-$ energy is calculated, and features of this dependence are investigated.
1006.3562
Juan Gonzalez-Fraile
O. J. P. Eboli, J. Gonzalez-Fraile, M. C. Gonzalez-Garcia
Scrutinizing the ZW+W- vertex at the Large Hadron Collider at 7 TeV
12 pages, 3 figures. One reference added, matches published version
Phys.Lett.B692:20-25,2010
10.1016/j.physletb.2010.07.013
YITP-SB-10--23
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the potential of the CERN Large Hadron Collider running at 7 TeV to search for deviations from the Standard Model predictions for the triple gauge boson coupling ZW+W- assuming an integrated luminosity of 1 fb^{-1}. We show that the study of W+W- and W^\pm Z productions, followed by the leptonic decay of the weak gauge bosons can improve the present sensitivity on the anomalous couplings \Delta g_1^Z, \Delta \kappa_Z, \lambda_Z, g_4^Z, and \tilde{\lambda}_Z at the 2\sigma level.
[ { "created": "Thu, 17 Jun 2010 20:00:23 GMT", "version": "v1" }, { "created": "Wed, 29 Jun 2011 09:36:54 GMT", "version": "v2" } ]
2011-06-30
[ [ "Eboli", "O. J. P.", "" ], [ "Gonzalez-Fraile", "J.", "" ], [ "Gonzalez-Garcia", "M. C.", "" ] ]
We analyze the potential of the CERN Large Hadron Collider running at 7 TeV to search for deviations from the Standard Model predictions for the triple gauge boson coupling ZW+W- assuming an integrated luminosity of 1 fb^{-1}. We show that the study of W+W- and W^\pm Z productions, followed by the leptonic decay of the weak gauge bosons can improve the present sensitivity on the anomalous couplings \Delta g_1^Z, \Delta \kappa_Z, \lambda_Z, g_4^Z, and \tilde{\lambda}_Z at the 2\sigma level.
hep-ph/9812535
Vassilis Spanos
A. B. Lahanas, V. C. Spanos and Vasilios Zarikas (Univ of Athens)
Charge asymmetry in two-Higgs doublet models
20 pages, LaTeX file, 5 eps figures included using epsfig macro. Major revision
Phys.Lett.B472:119,2000
10.1016/S0370-2693(99)01400-8
null
hep-ph
null
We discuss the features of a two-Higgs doublet model exhibiting a two stage phase transition. At finite temperatures electric charge violating stationary points are developed. In conjunction with {\em CP} violation in the Higgs or the Yukawa sector, the phase transition to the charge conserving vacuum, generates a net charge asymmetry $\Delta Q$, in the presence of heavy leptons, which may be well above the astrophysical bounds put on $\Delta Q$ unless the heavy leptons are sufficiently massive. This type of transition may be of relevance for supersymmetric extensions of the Standard Model, since it shares the same features, namely two Higgs doublets and similar {\em CP} violating sources.
[ { "created": "Thu, 31 Dec 1998 14:24:14 GMT", "version": "v1" }, { "created": "Thu, 28 Jan 1999 12:04:55 GMT", "version": "v2" }, { "created": "Mon, 4 Oct 1999 17:47:15 GMT", "version": "v3" } ]
2008-11-26
[ [ "Lahanas", "A. B.", "", "Univ of Athens" ], [ "Spanos", "V. C.", "", "Univ of Athens" ], [ "Zarikas", "Vasilios", "", "Univ of Athens" ] ]
We discuss the features of a two-Higgs doublet model exhibiting a two stage phase transition. At finite temperatures electric charge violating stationary points are developed. In conjunction with {\em CP} violation in the Higgs or the Yukawa sector, the phase transition to the charge conserving vacuum, generates a net charge asymmetry $\Delta Q$, in the presence of heavy leptons, which may be well above the astrophysical bounds put on $\Delta Q$ unless the heavy leptons are sufficiently massive. This type of transition may be of relevance for supersymmetric extensions of the Standard Model, since it shares the same features, namely two Higgs doublets and similar {\em CP} violating sources.
hep-ph/0104307
Juan M. Nieves Pamplona
Juan Nieves and Enrique Ruiz Arriola
The $S_{11}- N$(1535) and $-N$(1650) Resonances in Meson-Baryon Unitarized Coupled Channel Chiral Perturbation Theory
35 pages, LaTeX + 7 ps-figure files. Some minor mistakes have been corrected for and a new appendix discussing the matching to HBChPT has been also added
Phys.Rev. D64 (2001) 116008
10.1103/PhysRevD.64.116008
UG-DFM-10/01
hep-ph nucl-th
null
The $s-$wave meson-baryon scattering is analyzed for the strangeness S=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism and low energy constants are fitted to the elastic $\pi N $ phase-shifts and the $\pi^- p \to \eta n$ and $\pi^- p \to K^0 \Lambda$ cross section data. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths of the $S_{11}-$ $N$(1535) and $-N$(1650) resonances, in reasonable agreement with experiment. A good overall description of data, from $\pi N$ threshold up to 2 GeV, is achieved keeping in mind that the two pion production channel has not been included.
[ { "created": "Mon, 30 Apr 2001 08:39:56 GMT", "version": "v1" }, { "created": "Mon, 30 Jul 2001 16:24:45 GMT", "version": "v2" } ]
2009-11-07
[ [ "Nieves", "Juan", "" ], [ "Arriola", "Enrique Ruiz", "" ] ]
The $s-$wave meson-baryon scattering is analyzed for the strangeness S=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism and low energy constants are fitted to the elastic $\pi N $ phase-shifts and the $\pi^- p \to \eta n$ and $\pi^- p \to K^0 \Lambda$ cross section data. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths of the $S_{11}-$ $N$(1535) and $-N$(1650) resonances, in reasonable agreement with experiment. A good overall description of data, from $\pi N$ threshold up to 2 GeV, is achieved keeping in mind that the two pion production channel has not been included.
hep-ph/0410184
Mary Hall Reno
S. Kretzer (RIKEN-BNL and Brookhaven), M. H. Reno (Univ. of Iowa)
$\sigma_{DIS}(\nu N)$, NLO Perturbative QCD and O(1 GeV) Mass Corrections
6 pages, 7 figures, Talk given at 3rd International Workshop on Neutrino Nucleus Interactions in the Few GeV Region (NuInt04), Gran Sasso, Assergi, Italy, 17-21 Mar 2004
null
10.1016/j.nuclphysbps.2004.11.237
null
hep-ph
null
The deep-inelastic neutrino-nucleon cross section is one of the components of few GeV neutrino interactions. We present here our results for neutrino-isoscalar nucleon charged current scattering including perturbative next-to-leading order QCD corrections, target mass corrections, charm mass and lepton mass corrections.
[ { "created": "Wed, 13 Oct 2004 04:09:23 GMT", "version": "v1" } ]
2009-11-10
[ [ "Kretzer", "S.", "", "RIKEN-BNL and Brookhaven" ], [ "Reno", "M. H.", "", "Univ. of Iowa" ] ]
The deep-inelastic neutrino-nucleon cross section is one of the components of few GeV neutrino interactions. We present here our results for neutrino-isoscalar nucleon charged current scattering including perturbative next-to-leading order QCD corrections, target mass corrections, charm mass and lepton mass corrections.
0902.3718
Bo-Qiang Ma
Jun She, Jiacai Zhu, Bo-Qiang Ma
Pretzelosity $h_{1T}^{\perp}$ and quark orbital angular momentum
20 latex pages, 7 figures, to appear in PRD
Phys.Rev.D79:054008,2009
10.1103/PhysRevD.79.054008
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the pretzelosity distribution ($h_{1T}^{\perp}$), which is one of the eight leading twist transverse momentum dependent parton distributions (TMDs), in the light-cone formalism. We find that this quantity has a simple relation with the quark orbital angular momentum distribution, thus it may provide a new possibility to access the quark orbital angular momentum inside the nucleon. The pretzelosity distribution can manifest itself through the $\sin(3\phi_h-\phi_S)$ asymmetry in semi-inclusive deep inelastic scattering process. We calculate the $\sin(3\phi_h-\phi_S)$ asymmetry at HERMES, COMPASS and JLab kinematics, and present our prediction on different targets including the proton, deuteron and neutron targets. Inclusion of transverse momentum cut in data analysis could significantly enhance the $\sin(3\phi_h-\phi_S)$ asymmetry for future measurements.
[ { "created": "Sat, 21 Feb 2009 05:15:54 GMT", "version": "v1" }, { "created": "Mon, 9 Mar 2009 11:58:55 GMT", "version": "v2" } ]
2009-03-24
[ [ "She", "Jun", "" ], [ "Zhu", "Jiacai", "" ], [ "Ma", "Bo-Qiang", "" ] ]
We calculate the pretzelosity distribution ($h_{1T}^{\perp}$), which is one of the eight leading twist transverse momentum dependent parton distributions (TMDs), in the light-cone formalism. We find that this quantity has a simple relation with the quark orbital angular momentum distribution, thus it may provide a new possibility to access the quark orbital angular momentum inside the nucleon. The pretzelosity distribution can manifest itself through the $\sin(3\phi_h-\phi_S)$ asymmetry in semi-inclusive deep inelastic scattering process. We calculate the $\sin(3\phi_h-\phi_S)$ asymmetry at HERMES, COMPASS and JLab kinematics, and present our prediction on different targets including the proton, deuteron and neutron targets. Inclusion of transverse momentum cut in data analysis could significantly enhance the $\sin(3\phi_h-\phi_S)$ asymmetry for future measurements.
1505.05565
Anibal Medina
Anibal D. Medina
SUSY Implications from WIMP Annihilation into Scalars at the Galactic Center
4 pages, 3 figures, proceedings of the HPNP2015 conference
null
null
null
hep-ph astro-ph.GA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An excess in $\gamma$-rays emanating from the galactic centre has recently been observed in the Fermi-LAT data. We investigate the new exciting possibility of fitting the signal spectrum by dark matter annihilating dominantly to a Higgs-pseudoscalar pair. We show that the fit to the $\gamma$-ray excess for the Higgs-pseudoscalar channel can be just as good as for annihilation into bottom-quark pairs. This channel arises naturally in a full model such as the next-to-minimal supersymmetric Standard Model (NMSSM) and we find regions where dark matter relic density, the $\gamma$-ray signal and other experimental constraints, can all be satisfied simultaneously. Annihilation into scalar pairs allows for the possibility of detecting the Higgs or pseudoscalar decay into two photons, providing a smoking-gun signal of the model.
[ { "created": "Thu, 21 May 2015 00:45:34 GMT", "version": "v1" } ]
2015-05-22
[ [ "Medina", "Anibal D.", "" ] ]
An excess in $\gamma$-rays emanating from the galactic centre has recently been observed in the Fermi-LAT data. We investigate the new exciting possibility of fitting the signal spectrum by dark matter annihilating dominantly to a Higgs-pseudoscalar pair. We show that the fit to the $\gamma$-ray excess for the Higgs-pseudoscalar channel can be just as good as for annihilation into bottom-quark pairs. This channel arises naturally in a full model such as the next-to-minimal supersymmetric Standard Model (NMSSM) and we find regions where dark matter relic density, the $\gamma$-ray signal and other experimental constraints, can all be satisfied simultaneously. Annihilation into scalar pairs allows for the possibility of detecting the Higgs or pseudoscalar decay into two photons, providing a smoking-gun signal of the model.
hep-ph/0412264
Csaba Balazs
C. Balazs, M. Carena, A. Menon, D.E. Morrissey and C.E.M. Wagner
The Supersymmetric Origin of Matter
30 pages, 14 figures
Phys.Rev.D71:075002,2005
10.1103/PhysRevD.71.075002
ANL-HEP-PR-04-137, EFI-04-40, FERMILAB-PUB-04-397-T
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Minimal Supersymmetric extension of the Standard Model (MSSM) can provide the correct neutralino relic abundance and baryon number asymmetry of the universe. Both may be efficiently generated in the presence of CP violating phases, light charginos and neutralinos, and a light top squark. Due to the coannihilation of the neutralino with the light stop, we find a large region of parameter space in which the neutralino relic density is consistent with WMAP and SDSS data. We perform a detailed study of the additional constraints induced when CP violating phases, consistent with the ones required for baryogenesis, are included. We explore the possible tests of this scenario from present and future electron Electric Dipole Moment (EDM) measurements, direct neutralino detection experiments, collider searches and the b -> s gamma decay rate. We find that the EDM constraints are quite severe and that electron EDM experiments, together with stop searches at the Tevatron and Higgs searches at the LHC, will provide a definite test of our scenario of electroweak baryogenesis in the next few years.
[ { "created": "Fri, 17 Dec 2004 21:30:27 GMT", "version": "v1" }, { "created": "Thu, 22 Jan 2009 22:32:17 GMT", "version": "v2" } ]
2009-01-23
[ [ "Balazs", "C.", "" ], [ "Carena", "M.", "" ], [ "Menon", "A.", "" ], [ "Morrissey", "D. E.", "" ], [ "Wagner", "C. E. M.", "" ] ]
The Minimal Supersymmetric extension of the Standard Model (MSSM) can provide the correct neutralino relic abundance and baryon number asymmetry of the universe. Both may be efficiently generated in the presence of CP violating phases, light charginos and neutralinos, and a light top squark. Due to the coannihilation of the neutralino with the light stop, we find a large region of parameter space in which the neutralino relic density is consistent with WMAP and SDSS data. We perform a detailed study of the additional constraints induced when CP violating phases, consistent with the ones required for baryogenesis, are included. We explore the possible tests of this scenario from present and future electron Electric Dipole Moment (EDM) measurements, direct neutralino detection experiments, collider searches and the b -> s gamma decay rate. We find that the EDM constraints are quite severe and that electron EDM experiments, together with stop searches at the Tevatron and Higgs searches at the LHC, will provide a definite test of our scenario of electroweak baryogenesis in the next few years.
1506.07145
Fedor Simkovic
Dusan Stefanik, Rastislav Dvornicky, Fedor Simkovic, Petr Vogel
The light neutrino exchange mechanism of the $0\nu\beta\beta$-decay with left- and right-handed leptonic and hadronic currents revisited
15 pages, 8 figures
Phys. Rev. C 92, 055502 (2015)
10.1103/PhysRevC.92.055502
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The extension of Majorana neutrino mass mechanism of the neutrinoless double-beta decay ($0\nu\beta\beta$) with the inclusion of right-handed leptonic and hadronic currents is revisited. While only the exchange of light neutrinos is assumed, the $s_{1/2}$ and $p_{1/2}$-states of emitted electrons as well as recoil corrections to the nucleon currents are taken into account. Within the standard approximations the decay rate is factorized into a sum of products of kinematical phase-space factors, nuclear matrix elements and the fundamental parameters that characterize the lepton number violation. Unlike in the previous treatments the induced pseudoscalar term of hadron current is included, resulting in additional nuclear matrix elements. An improved numerical computation of the phase-space factors is presented, based on the exact Dirac wave functions of the $s_{1/2}$ and $p_{1/2}$ electrons with finite nuclear size and electron screening taken into account. The dependence of values of these phase-space factors on the different approximation schemes used in evaluation of electron wave functions is discussed. The upper limits for effective neutrino mass and the parameters $\langle\lambda\rangle$ and $\langle\eta\rangle$ characterizing the right-handed current mechanism are deduced from data on the $0\nu\beta\beta$-decay of $^{76}$Ge and $^{136}$Xe using nuclear matrix elements calculated within the nuclear shell model and quasiparticle random phase approximation. The differential decay rates, i.e. the angular correlations and the single electron energy distributions for various combinations of the total lepton number violating parameters that can help to disentangle the possible mechanism are described and discussed.
[ { "created": "Tue, 23 Jun 2015 19:14:34 GMT", "version": "v1" }, { "created": "Mon, 6 Jul 2015 16:10:19 GMT", "version": "v2" } ]
2015-11-11
[ [ "Stefanik", "Dusan", "" ], [ "Dvornicky", "Rastislav", "" ], [ "Simkovic", "Fedor", "" ], [ "Vogel", "Petr", "" ] ]
The extension of Majorana neutrino mass mechanism of the neutrinoless double-beta decay ($0\nu\beta\beta$) with the inclusion of right-handed leptonic and hadronic currents is revisited. While only the exchange of light neutrinos is assumed, the $s_{1/2}$ and $p_{1/2}$-states of emitted electrons as well as recoil corrections to the nucleon currents are taken into account. Within the standard approximations the decay rate is factorized into a sum of products of kinematical phase-space factors, nuclear matrix elements and the fundamental parameters that characterize the lepton number violation. Unlike in the previous treatments the induced pseudoscalar term of hadron current is included, resulting in additional nuclear matrix elements. An improved numerical computation of the phase-space factors is presented, based on the exact Dirac wave functions of the $s_{1/2}$ and $p_{1/2}$ electrons with finite nuclear size and electron screening taken into account. The dependence of values of these phase-space factors on the different approximation schemes used in evaluation of electron wave functions is discussed. The upper limits for effective neutrino mass and the parameters $\langle\lambda\rangle$ and $\langle\eta\rangle$ characterizing the right-handed current mechanism are deduced from data on the $0\nu\beta\beta$-decay of $^{76}$Ge and $^{136}$Xe using nuclear matrix elements calculated within the nuclear shell model and quasiparticle random phase approximation. The differential decay rates, i.e. the angular correlations and the single electron energy distributions for various combinations of the total lepton number violating parameters that can help to disentangle the possible mechanism are described and discussed.
1412.1603
Reza Khosravi
R. Khosravi and D. Hatami
Decay constants and masses of light tensor mesons ($J^P =2^+$)
null
Int. J. Mod. Phys. A 30, 1550106 (2015)
10.1142/S0217751X15501067
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the masses and decay constants of the light tensor mesons with quantum numbers $J^P =2^+$ in the framework of the QCD sum rules in the standard model. The non-perturbative contributions up to dimension-$5$ as important terms of the operator product expansion are considered.
[ { "created": "Thu, 4 Dec 2014 10:08:42 GMT", "version": "v1" } ]
2018-04-17
[ [ "Khosravi", "R.", "" ], [ "Hatami", "D.", "" ] ]
We calculate the masses and decay constants of the light tensor mesons with quantum numbers $J^P =2^+$ in the framework of the QCD sum rules in the standard model. The non-perturbative contributions up to dimension-$5$ as important terms of the operator product expansion are considered.