Nuclear Theory·nucl-th

Monday·January 23, 2017

6 papers—2 primary·4 cross-listed

01
[Submitted on 20 Jan 2017]
Strongly screening on electron capture for Nuclides $^{52, 53, 59, 60}$ Fe by the Shell-Model Monte Carlo method in pre-supernova
Jing-Jing Liu · Qiu-He Peng · Dong-Mei Liu
The death of the massive stars due to supernova explosion is a key ingredient in stellar evolution, stellar population synthesis. The electron capture (EC) plays a vital role in supernovae explosions. According to the Shell-Model Monte Carlo (SMMC) method, basing onthe Random Phase Approximation (RPA) and Linear Response Theory Model (LRTM), we study the strongly screening EC rates of nuclides $^{52, 53, 59, 60}$ Fe in presupernova. The results show that the screening rates can decrease about 18.66\%. We compare our results with those of Fuller et al. (FFN), Aufderheide et al. (AUFD), and Nabi et al. (NKK)in the case with and without strong electron screening(SES). For the case without SES, our calculations are in very good agreement with those of AUFD in relatively high density surroundings and the maximum error is within 0.35\% at $ρ_{7} = 100$ (e. g., even-even nuclei $^{60}$ Fe). However, for odd-A nuclei $^{59}$ Fe, our rates are close to one, one, two order magnitude smaller than those of FFN, AUFD, and NKK. For the case with SES, our screening results are about three, two orders magnitude, and 7.27\% lower than those of FFN, AUFD, NKK for $^{60}$ Fe, respectively, and it is lower about two, two orders magnitude, and 12.42\% than those of FFN, AUFD, NKK for odd-A nuclide $^{59}$ Fe.
Comments:
12 pages, 9 figures. arXiv:1312.7502,accepted for publication in chinese physics C
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
1701.05771 [pdf]
CPC(2017)·7 citations
02
[Submitted on 20 Jan 2017]
Nonlocal nucleon-nucleus interactions in (d,p) reactions: Role of the deuteron D-state
G.W. Bailey · N.K. Timofeyuk · J.A. Tostevin
Theoretical models of the (d,p) reaction are exploited for both nuclear astrophysics and spectroscopic studies in nuclear physics. Usually, these reaction models use local optical model potentials to describe the nucleon- and deuteron-target interactions. Within such a framework the importance of the deuteron D-state in low-energy reactions is normally associated with spin observables and tensor polarization effects - with very minimal influence on differential cross sections. In contrast, recent work that includes the inherent nonlocality of the nucleon optical model potentials in the Johnson-Tandy adiabatic-model description of the (d,p) transition amplitude, which accounts for deuteron break-up effects, shows sensitivity of the reaction to the large n-p relative momentum content of the deuteron wave function. The dominance of the deuteron D-state component at such high momenta leads to significant sensitivity of calculated (d,p) cross sections and deduced spectroscopic factors to the choice of deuteron wave function [Phys. Rev. Lett. {\bf 117}, 162502 (2016)]. We present details of the Johnson-Tandy adiabatic model of the (d,p) transfer reaction generalized to include the deuteron D-state in the presence of nonlocal nucleon-target interactions. We present exact calculations in this model and compare these to approximate (leading-order) solutions. The latter, approximate solutions can be interpreted in terms of local optical potentials, but evaluated at a shifted value of the energy in the nucleon-target system. This energy shift is increased when including the D-state contribution. We also study the expected dependence of the D-state effects on the separation energy and orbital angular momentum of the transferred nucleon. Their influence on the spectroscopic information extracted from (d,p) reactions is quantified for a particular case of astrophysical significance.
Comments:
11 pages, 7 figures, accepted in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1701.05853 [pdf]
PRC(2017)·18 citations
03
[Submitted on 20 Jan 2017] (cross-list from astro-ph.HE)
Effect of nuclear saturation parameters on possible maximum mass of neutron stars
Hajime Sotani🇯🇵
In order to systematically examine the possible maximum mass of neutron stars, which is one of the important properties characterizing the physics in high-density region, I construct neutron star models by adopting phenomenological equations of state with various values of nuclear saturation parameters for low-density region, which are connected to the equation of state for high-density region characterized by the possible maximum sound velocity in medium. I derive an empirical formula for the possible maximum mass of neutron star. If massive neutron stars are observed, it could be possible to get a constraint on the possible maximum sound velocity for high-density region.
Comments:
accepted for publication in PRC
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1701.05646 [pdf]
PRC(2017)·19 citations
04
[Submitted on 20 Jan 2017] (cross-list from hep-ph)
Interaction of real and virtual $p p ˉ$ pairs in $J / ψ \to p p ˉ γ (ρ, ω)$ decays
A. I. Milstein🇷🇺 · S. G. Salnikov🇷🇺
The $p p ˉ$ invariant mass spectra of the processes $J / ψ \to p p ˉ ω$ , $J / ψ \to p p ˉ ρ$ , and $J / ψ \to p p ˉ γ$ close to the $p p ˉ$ threshold are calculated by means of the $N N ˉ$ optical potential. The potential model for $N N ˉ$ interaction in the $^{1} S_{0}$ state is proposed. The parameters of the model are obtained by fitting the cross section of $N N ˉ$ scattering together with the $p p ˉ$ invariant mass spectra of the $J / ψ$ decays. Good agreement with the available experimental data is achieved. Using our potential and the Green's function approach we also describe the peak in the $η^{'} π^{+} π^{-}$ invariant mass spectrum in the decay $J / ψ \to γ η^{'} π^{+} π^{-}$ in the energy region near the $N N ˉ$ threshold.
Comments:
13 pages, 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1701.05741 [pdf]
NPA(2017)·18 citations
05
[Submitted on 20 Jan 2017] (cross-list from hep-ph)
Inclusive production of small radius jets in heavy-ion collisions
Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸
We develop a new formalism to describe the inclusive production of small radius jets in heavy-ion collisions, which is consistent with jet calculations in the simpler proton-proton system. Only at next-to-leading order (NLO) and beyond, the jet radius parameter $R$ and the jet algorithm dependence of the jet cross section can be studied and a meaningful comparison to experimental measurements is possible. We are able to consistently achieve NLO accuracy by making use of the recently developed semi-inclusive jet functions within Soft Collinear Effective Theory (SCET). In addition, single logarithms of the jet size parameter $α_{s}^{n} ln^{n} R$ are resummed to next-to-leading logarithmic (NLL $_{R}$ ) accuracy. The medium modified semi-inclusive jet functions are obtained within the framework of SCET with Glauber gluons that describe the interaction of jets with the medium. We present numerical results for the suppression of inclusive jet cross sections in heavy ion collisions at the LHC and the formalism developed here can be extended directly to corresponding jet substructure observables.
Comments:
8 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1701.05839 [pdf]
PLB(2017)·78 citations
06
[Submitted on 20 Jan 2017] (cross-list from hep-ph)
Transverse densities of octet baryons from chiral effective field theory
Jose Manuel Alarcón🇺🇸 · Astrid N. Hiller Blin🇪🇸 · C. Weiss🇺🇸
Transverse densities describe the distribution of charge and current at fixed light-front time and provide a frame-independent spatial representation of hadrons as relativistic systems. We calculate the transverse densities of the octet baryons at peripheral distances b = O(M_pi^{-1}) in an approach combining chiral effective field theory (ChEFT) and dispersion analysis. The densities are represented as dispersive integrals of the imaginary parts of the baryon electromagnetic form factors in the timelike region (spectral functions). The spectral functions on the two-pion cut at t > 4 M_pi^2 are computed using relativistic ChEFT with octet and decuplet baryons in the EOMS renormalization scheme. The calculations are extended into the rho-meson mass region, using a dispersive method that incorporates the timelike pion form-factor data. The approach allows us to construct densities at distances b > 1 fm with controlled uncertainties. Our results provide insight into the peripheral structure of nucleons and hyperons and can be compared with empirical densities and lattice-QCD calculations.
Comments:
Proceedings of Light Cone 2016
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1701.05871 [pdf]
Few Body Syst.(2017)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Strongly screening on electron capture for Nuclides 52,53,59,60Fe by the Shell-Model Monte Carlo method in pre-supernova

Nonlocal nucleon-nucleus interactions in (d,p) reactions: Role of the deuteron D-state

Effect of nuclear saturation parameters on possible maximum mass of neutron stars

Interaction of real and virtual ppˉ​ pairs in J/ψ→ppˉ​γ(ρ,ω) decays

Inclusive production of small radius jets in heavy-ion collisions

Transverse densities of octet baryons from chiral effective field theory

Affiliations

Strongly screening on electron capture for Nuclides $^{52, 53, 59, 60}$ Fe by the Shell-Model Monte Carlo method in pre-supernova

Interaction of real and virtual $p p ˉ$ pairs in $J / ψ \to p p ˉ γ (ρ, ω)$ decays