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Nuclear Theory·nucl-th

Friday·January 7, 2022

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    [Submitted on 6 Jan 2022]

    Proto-neutron star evolution with improved charged-current neutrino-nucleon interactions

    A Pascal (LUTH (UMR\_8102))🇫🇷 · J Novak (LUTH (UMR\_8102))🇫🇷 · M Oertel (LUTH (UMR\_8102))🇫🇷

    We perform simulations of the Kelvin-Helmholtz cooling phase of proto-neutron stars with a new numerical code in spherical symmetry and using the quasi-static approximation. We use for the first time the full set of charged-current neutrino-nucleon reactions, including neutron decay and modified Urca processes, together with the energy-dependent numerical representation for the inclusion of nuclear correlations with random-phase approximation. Moreover, convective motions are taken into account within the mixing-length theory. As we vary the assumptions for computing neutrino-nucleon reaction rates, we show that the dominant effect on the cooling timescale, neutrino signal and composition of the neutrino-driven wind comes from the inclusion of convective motion. Computation of nuclear correlations within the random phase approximation, as compared to mean field approach, has a relatively small impact.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2201.01955 [pdf]
    MNRAS(2022)·63 citations
  2. 02

    [Submitted on 6 Jan 2022]

    Shell-model study on properties of proton dripline nuclides with Z, N = 30-50 including uncertainty analysis

    Boshuai Cai · Guangshang Chen · Cenxi Yuan · Jianjun He

    The binding energies and proton separation energies of nuclides with are investigated, based on the shell model with an uncertainty analysis through statistical methods. Several formulas are used to obtain the binding energies and proton separation energies according to the shell-model calculations. The non-parametric Bootstrap method is applied to establish an uncertainty decomposition and recomposition framework. Moreover, it is used to estimate the stability of proton(s) emission for each nuclide. Two formulas for calculating the binding energies with a systematic uncertainty of MeV are proposed, and a reliable extrapolation ability is examined. These binding energy formulas deduce similar forms of respective and energies, which predict the extension of the nuclear boundary of this region. A nice description of the binding energies and proton separation energies is provided. The one- and two-proton separation energies and partial half-lives of proton emitting are predicted, thus showing a new dripline. Besides, there are 30 unstable nuclides predicted to be bound against proton(s)-emission. These nuclear properties will be useful in nuclear astrophysics.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2201.02083 [pdf]
    CPC(2022)·2 citations
  3. 03

    [Submitted on 6 Jan 2022]

    Collective expansion in pp collisions using the Tsallis statistics

    J.B. Gu🇨🇳 · C.Y. Li🇨🇳 · Q. Wang🇨🇳 · W.C. Zhang🇨🇳 · H. Zheng🇨🇳

    We investigate the transverse momentum () spectra of identified hadrons in minimum-bias proton-proton (pp) collisions at a centre-of-mass energy () of 0.9, 2.76, 5.02, 7 and 13 TeV in the framework of Tsallis-blast wave (TBW) model. It is found that the model describes well the particle spectra up to 10 GeV/c. The radial flow () increases with the collision energy. The degrees of non-equilibrium () and the Tsallis temperature parameter () show a similar behaviour, but with a much weaker trend. With this dependence of the freeze-out parameters on the collision energy, we evaluate , and in pp collisions at 8 and 14 TeV and predict the particle spectra at these two energies. Moreover, in order to investigate the multiplicity dependence of the freeze-out parameters, the TBW model is extended to the spectra at different charged-particle multiplicity classes in pp collisions at 7 and 13 TeV. It is observed that at both energies the radial flow increases with the multiplicity while the degree of non-equilibrium shows an opposite behaviour, which is similar to that observed in proton-nucleus (pA) and nucleus-nucleus (AA) collisions at the Large Hadron Collider (LHC) energies. However, the Tsallis temperature parameter increases with the multiplicity, which is opposite to the trend in pA and AA collisions. At similar multiplicities, the radial flow in pp collisions is stronger than those in pA and AA collisions, indicating that the size of the colliding system has significant effects on the final state particle dynamics. Finally, we apply an additional flow correction to the Tsallis temperature parameter and find that the doppler-corrected temperature parameter almost scales with the multiplicity in a uniform way, despite the difference in the colliding system and collision energy.

    Comments:
    13 pages, 9 figures, 6 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2201.02091 [pdf]
    J.Phys.G(2022)·22 citations
  4. 04

    [Submitted on 6 Jan 2022]

    Anatomy of octupole correlations in Zr with a symmetry-restored multidimensionally-constrained covariant density functional theory

    Yu-Ting Rong · Xian-Ye Wu · Bing-Nan Lu · Jiang-Ming Yao

    A recent analysis based on the STAR measurement in relativistic heavy-ion collision experiments provides evidence of octupole correlation in the ground state of Zr, the description of which presents a challenge to nuclear structure models. In this work, we perform projection-after-variation calculations for Zr based on a multidimensionally-constrained relativistic Hartree-Bogoliubov model. Our results show that an octupole deformed shape is favored in energy after symmetry restoration, and this phenomenon cannot be reproduced in the pure mean-field calculations. These complex structures originate from the competition among various shell structures in this mass region. Our results suggest that the allowance of symmetry breaking at the mean-field level and the restoration of broken symmetries are essential elements for understanding the structure of Zr in density functional theories.

    Comments:
    10 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2201.02114 [pdf]
    PLB(2023)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE