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Nuclear Theory·nucl-th

Thursday·January 21, 2016

12 papers—7 primary·5 cross-listed

All12Primary7Cross-lists5
  1. 01

    Superfluid fission dynamics with microscopic approaches

    C. Simenel · G. Scamps🇫🇷 · D. Lacroix🇫🇷 · A. S. Umar

    Recent progresses in the description of the latter stage of nuclear fission are reported. Dynamical effects during the descent of the potential towards scission and in the formation of the fission fragments are studied with the time-dependent Hartree-Fock approach with dynamical pairing correlations at the BCS level. In particular, this approach is used to compute the final kinetic energy of the fission fragments. Comparison with experimental data on the fission of 258Fm are made.

    nucl-thEPJ Web Conf.(2016)·4 citations
  2. 02

    Beyond Wigner's isobaric multiplet mass equation: Effect of charge-symmetry-breaking interaction and Coulomb polarization

    J. M. Dong · J. Z. Gu · Y. H. Zhang · W. Zuo · L. J. Wang · Yu. A. Litvinov · Y. Sun

    The quadratic form of the isobaric multiplet mass equation (IMME), which was originally suggested by Wigner and has been generally regarded as valid, is seriously questioned by recent high-precision nuclear mass measurements. The usual resolution to this problem is to add empirically the cubic and quartic -terms to characterize the deviations from the IMME, but finding the origin of these terms remains an unsolved difficulty. Based on a strategy beyond the Wigner's first-order perturbation, we derive explicitly the cubic and quartic -terms. These terms are shown to be generated by the effective charge-symmetry breaking and charge-independent breaking interactions in nuclear medium combined with the Coulomb polarization effect. Calculations for the - and lower -shells explore a systematical emergence of the cubic -term, suggesting a general deviation from the original IMME. Intriguingly, the magnitude of the deviation exhibits an oscillation-like behavior with mass number, modulated by the shell effect.

    nucl-thPRC(2019)·16 citations
  3. 03

    Time-dependent Hartree-Fock Study of Octupole Vibrations in doubly magic nuclei

    C. Simenel · J. Buete · K. Vo-Phuoc

    Octupole vibrations are studied in some doubly magic nuclei using the time-dependent Hartree-Fock (TDHF) theory with a Skyrme energy density functional. Through the use of the linear response theory, the energies and transition amplitudes of the low-lying vibrational modes for each of the nuclei were determined. Energies were found to be close to experimental results. However, transition amplitudes, quantified by the deformation parameter , are underestimated by TDHF. A comparison with single-particle excitations on the Hartree-Fock ground-state shows that the collective octupole vibrations have their energy lowered due to attractive RPA residual interaction.

    nucl-thEPJ Web Conf.(2016)·1 citation
  5. 05

    Search for scaling onset in exclusive reactions with the lightest nuclei

    Yu.N. Uzikov🇷🇺

    The dimensional scaling of the differential cross sections of binary reactions , where is given by constituent quark counting rules, was predicted for asymptotically high energies and transferred momenta at (here and are the Mandelstam variables and denotes a hadron mass), but manifested itself at surprisingly moderate energies of few GeV at large fixed cms angles . This behaviour is observed not only in reactions with free hadrons, but with the deuteron and too both for electromagnetic and pure hadronic interactions. One may suppose that observed scaling points out to effective restoration of near-conformal and, probably, chiral symmetry in these processes. A systematical experimental study of the scaling behaviour of the reactions with the deuteron, , , and nuclei is still absent. We consider a possibility to carry out this study in collisions at the JINR Nuclotron.

    nucl-thEPJA(2016)·3 citations
  6. 06

    The Hyperon Puzzle in Neutron Stars

    Ignazio Bombaci🇮🇹

    The so called "hyperon puzzle", i.e. the difficulty to reconcile the measured masses of neutron stars (NSs) with the presence of hyperons in their interiors, is one of the hot topics in astrophysics which is stimulating copious experimental and theoretical research in hypernuclear physics. After illustrating the origin of the hyperon puzzle, I discuss some of its possible solutions, and particularly those related to the role of hyperonic two- and three-body interactions on the equation of state of dense matter. Afterward, I discuss a possibility to circumvent the hyperon puzzle allowing for the presence of strangeness in NSs in the form of deconfined strange quark matter, and thus considering the so called quark stars, i.e. hybrid stars or strange stars. Finally I discuss the astrophysical consequences of the possible conversion process of an hadronic star to a quark star.

    nucl-thastro-ph.HEJPS Conf.Proc.(2017)·81 citations
  7. 07

    Origin of the mass splitting of elliptic anisotropy in a multiphase transport model

    Hanlin Li🇨🇳 · Liang He🇺🇸 · Zi-Wei Lin🇺🇸 · Denes Molnar🇺🇸 · Fuqiang Wang🇺🇸 · Wei Xie🇺🇸

    The mass splitting of elliptic anisotropy () at low transverse momentum is considered as a hallmark of hydrodynamic collective flow. We investigate a multiphase transport (AMPT) model where the is mainly generated by an anisotropic escape mechanism, not of the hydrodynamic flow nature, and where mass splitting is also observed. We demonstrate that the mass splitting in AMPT is small right after hadronization (especially when resonance decays are included); the mass splitting mainly comes from hadronic rescatterings, even though their contribution to the overall charged hadron is small. These findings are qualitatively the same as those from hybrid models that combine hydrodynamics with a hadron cascade. We further show that there is no qualitative difference between heavy ion collisions and small system collisions. Our results indicate that the mass splitting is not a unique signature of hydrodynamic collective flow and thus cannot distinguish whether the elliptic flow is generated mainly from hydrodynamics or the anisotropic parton escape.

    nucl-thnucl-exPRC(2016)·22 citations

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first authorsco-authorsvia INSPIRE