Nuclear Theory·nucl-th

Monday·January 21, 2019

10 papers—7 primary·3 cross-listed

01
[Submitted on 17 Jan 2019]
Effects of medium modifications of nucleon form factors on neutrino scattering in dense matter
Parada T. P. Hutauruk🇰🇷 · Yongseok Oh🇰🇷 · K.Tsushima🇰🇷
Effects of the in-medium modifications of nucleon form factors on neutrino interaction in dense matter are presented by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field and the quark-meson coupling models are respectively adopted for the effective nucleon mass and in-medium nucleon form factors. We calculate the cross-section of neutrino scattering as well as the neutrino mean free path. We found the cross sections of neutrino scattering in cold nuclear medium decreases when the in-medium modifications of the nucleon weak and electromagnetic form factors are taken into account.This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density.
Comments:
4 pages, 2 figures, accepted for the QNP2018 proceedings, a talk given at QNP2018, 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Ibaraki, Japan
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1901.05986 [pdf]
JPS Conf.Proc.(2019)·4 citations
02
[Submitted on 17 Jan 2019]
Pion structure in a nuclear medium
Parada. T. P. Hutauruk🇰🇷 · Yongseok Oh🇰🇷 · K. Tsushima🇰🇷
The structure and electroweak properties of the pion in symmetric nuclear matter are presented in the framework of the Nambu--Jona-Lasinio model. The pion is described as a bound state of a dressed quark-antiquark pair governed by the Bethe-Salpeter equation. For the in-medium current-light-quark properties we use the quark-meson coupling model, which describes successfully the properties of hadron in a nuclear medium. We found that the light-quark condensates, the pion decay constant and pion-quark coupling constant decrease with increasing nuclear matter density. We then predict the modifications of the charge radius of the charged pion in nuclear matter.
Comments:
4 pages, 6 figures, accepted version for the QNP2018 proceedings, 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Ibaraki, Japan
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1901.06008 [pdf]
JPS Conf.Proc.(2019)·1 citation
03
[Submitted on 17 Jan 2019]
Effect of Coulomb energy on Skyrmions
Nana Ma🇨🇳 · Chris James Halcrow🇬🇧 · Hongfei Zhang🇨🇳
The Coulomb effect, an essential ingredient in nuclear systems, is quantitatively investigated for certain Skyrmions within the Skyrme model. To do this we calculate the Coulomb energy from numerically generated multi-Skyrmions and, simultaneously, introduce an effective alpha-like particle approximation for large Skyrmions with baryon number $B$ , where $B$ is a multiple of four. The calculated Coulomb energies and the corresponding fitted curve from this approximation match well with the results from the numerical method, as well as the behavior of the Coulomb energy in the semi-empirical mass formula. The Skyrme model correctly reproduces the well known results for the Coulomb energy of nuclei. This suggests that the alpha-particles can be used as the fundamental degrees of freedom in the Skyrme model. The Coulomb effect on the binding energy of the Skyrmions increases with baryon number but has a small effect overall. However, the effect could be significantly more pronounced for loosely bound Skyrme models.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1901.06025 [pdf]
PRC(2019)·9 citations
04
[Submitted on 18 Jan 2019]
Physics of even-even superheavy nuclei with 96 < Z < 110 in the Quark-Meson-Coupling Model
J.R.Stone🇬🇧 · K.Morita🇯🇵 · P.A.M. Guichon🇫🇷 · A.W.Thomas🇦🇺
The Quark-Meson-Coupling (QMC) model has been applied to the study of the properties of even-even super-heavy nuclei with 96 < Z < 110, over a wide range of neutron numbers. The aim is to identify the deformed shell gaps at N = 152 and N = 162 predicted in macroscopic-microscopic (macro-micro) models, in a model based on the mean-field Hartree-Fock+BCS approximation. The predictive power of the model has been tested on proton and neutron spherical shell gaps in light doubly closed (sub)shell nuclei. In the super-heavy region, the ground state binding energies of 98 < Z < 110 and 146 < N < 160 differ, in the majority of cases, from the measured values by less than 2.5 MeV, with the deviation decreasing with increasing Z and N. The axial quadrupole deformation parameter, calculated over the range of neutron numbers 138 < N < 184, revealed a prolate-oblate coexistence and shape transition around N = 168, followed by an oblate-spherical transition towards the expected N = 184 shell closure in Cm, Cf, Fm and No. The closure is not predicted in Rf, Sg, Hs and Ds as another shape transition to a highly deformed shape in Sg, Hs and Ds for N > 178 appears, while 288Rf (N = 184) remains oblate. The bulk properties predicted by QMC are found to have a limited sensitivity to the deformed shell gaps at N = 152 and 162. However, the evolution of the neutron single-particle spectra with 0 < beta2 < 0.55 gives unambiguous evidence for the location and size of the N = 152 and 162 gaps as a function of Z and N. In addition, the neutron number dependence of neutron pairing energies provides supporting evidence for existence of the energy gaps.
Comments:
48 pages, 22 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1901.06064 [pdf]
PRC(2019)·27 citations
05
[Submitted on 18 Jan 2019]
Effects of charge symmetry breaking on form factors of the pion and kaon
Parada T. P. Hutauruk🇰🇷 · Wolfgang Bentz🇯🇵 · Ian C. Cloët🇺🇸 · Anthony Thomas🇦🇺
Effects of charge symmetry breaking associated with the $u$ and $d$ quark mass difference in the elastic form factors of the pion and kaon are presented. We use a confining version of the Nambu--Jona-Lasinio model. The pion and kaon are described as a dressed quark and antiquark bound states governed by the Bethe-Salpeter equation, and exhibit the properties of Goldstone bosons, with the pion mass difference given by $m_{π^{+}}^{2} - m_{π^{0}}^{2} \propto (m_{u} - m_{d})^{2}$ as demanded by dynamical chiral symmetry breaking. We found significant charge symmetry breaking effects for realistic current quark mass ratios ( $m_{u} / m_{d} \sim 0.5$ ) in the quark electromagnetic form factors of the pion and kaon. We also report the effects of charge symmetry breaking on the parton distribution functions, which are rather smaller than those found in the electromagnetic form factors.
Comments:
4 pages, 5 figures, accepted version for the QNP2018 proceedings, 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Ibaraki, Japan
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1901.06068 [pdf]
JPS Conf.Proc.(2019)·3 citations
06
[Submitted on 18 Jan 2019]
Description of the recently observed hypernucleus $^{15}_{Ξ^{-}}$ C within a quark-meson coupling model
R. Shyam🇮🇳 · K. Tsushima🇧🇷
We investigate within a quark-meson coupling (QMC) model, the structure of the bound $Ξ^{-}$ hypernucleus $^{15}_{Ξ^{-}}$ C ( $^{14}$ N + $Ξ^{-}$ ), which has been observed in a recent analysis of the KEK-E373 experiment. In the QMC model, light quarks in nonoverlapping nucleon and $Ξ^{-}$ bags interact self-consistently with isoscalar-scalar ( $σ$ ), isoscalar-vector ( $ω$ ), and isovector-vector ( $ρ$ ) mesons in the mean field approximation. The parameters of the model (quark-meson coupling constants and masses) are mostly fixed from the nuclear matter saturation properties. The QMC model closely reproduces the separation energies of the two $Ξ^{-}$ hyperon states in $^{15}_{Ξ^{-}}$ C reported in the KEK-E373 analysis, and identifies their quantum numbers. We also make predictions for the cross sections for the production of the $^{15}_{Ξ^{-}}$ C hypernuclear specta in the ( $K^{-}, K^{+}$ ) reaction on a $^{15}$ O target within a covariant effective Lagrangian model using the $Ξ^{-}$ bound state spinors obtained within the same QMC model.
Comments:
17 Pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1901.06090 [pdf]
11 citations
07
[Submitted on 17 Jan 2019]
Charmonia decay widths in magnetized matter using a model for composite hadrons
Amruta Mishra🇮🇳 · S.P. Misra🇮🇳
The decay widths of the charmonium states to $D D ˉ$ in isospin asymmetric nuclear matter in the presence of a magnetic field are studied, using a field theoretical model for composite hadrons with quark/antiquark constituents. The medium modifications of these partial decay widths arise due to the changes in the masses of the decaying charmonium state and the produced $D$ and $D ˉ$ mesons in the magnetized hadronic matter, calculated within a chiral effective model. The decay widths are computed using the light quark--antiquark pair creation term of the free Dirac Hamiltonian in terms of the constituent quark field operators. The results of the present investigation are compared with the in-medium decay widths obtained within the $^{3} P_{0}$ model. Within the $^{3} P_{0}$ model, the charmonium decay widths are calculated using the creation of a light quark--antiquark pair in the $^{3} P_{0}$ state. In the presence of a magnetic field, the Landau level contributions give rise to positive shifts in the masses of the charged $D$ and $D ˉ$ mesons. This leads to the decay of charmonium to the charged $D^{+} D^{-}$ to be suppressed as compared to the neutral $D D ˉ$ pair in symmetric nuclear matter, whereas in asymmetric nuclear matter, the larger mass drop of the $D^{+} D^{-}$ pair, as compared to the $D^{0} D^{0} ˉ$ pair leads to the production of charged open charm meson pairs to be enhanced as compared to the charmonium decay channel to $D^{0} D^{0} ˉ$ .
Comments:
Major revision, 26 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1901.06259 [pdf]
5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effects of medium modifications of nucleon form factors on neutrino scattering in dense matter

Pion structure in a nuclear medium

Effect of Coulomb energy on Skyrmions

Physics of even-even superheavy nuclei with 96 < Z < 110 in the Quark-Meson-Coupling Model

Effects of charge symmetry breaking on form factors of the pion and kaon

Description of the recently observed hypernucleus 15Ξ−​C within a quark-meson coupling model

Charmonia decay widths in magnetized matter using a model for composite hadrons

Affiliations

Description of the recently observed hypernucleus $^{15}_{Ξ^{-}}$ C within a quark-meson coupling model