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Nuclear Theory·nucl-th

Friday·May 31, 2019

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    [Submitted on 29 May 2019]

    Neutron-Star-Merger Equation of State

    Veronica Dexheimer🇺🇸 · Constantinos Constantinou🇺🇸 · Elias R. Most🇩🇪 · L. Jens Papenfort🇩🇪 · Matthias Hanauske🇩🇪 · Stefan Schramm🇩🇪 · Horst Stoecker🇩🇪 · Luciano Rezzolla🇩🇪

    In this work, we discuss the dense matter equation of state (EOS) for the extreme range of conditions encountered in neutron stars and their mergers. The calculation of the properties of such an EOS involves modeling different degrees of freedom (such as nuclei, nucleons, hyperons, and quarks), taking into account different symmetries, and including finite density and temperature effects in a thermodynamically consistent manner. We begin by addressing subnuclear matter consisting of nucleons and a small admixture of light nuclei in the context of the excluded volume approach. We then turn our attention to supranuclear homogeneous matter as described by the Chiral Mean Field (CMF) formalism. Finally, we present results from realistic neutron-star-merger simulations performed using the CMF model that predict signatures for deconfinement to quark matter in gravitational wave signals.

    Comments:
    Contribution to the Special Issue "Compact Stars in the QCD Phase Diagram and in the Multi-Messenger Era of Astronomy" dedicated to the conference: Compact Stars in the QCD Phase Diagram VII
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    1905.12658 [pdf]
    Universe(2019)·10 citations
  2. 02

    [Submitted on 30 May 2019]

    Two-particle transfer processes as a signature of shape phase transition in Zirconium isotopes

    J.A. Lay · A. Vitturi · L. Fortunato · Y. Tsunoda · T. Togashi · T. Otsuka

    We explore two-particle transfer reactions as a unique probe of the occurence of shape coexistence in shape phase transitions. The (t,p) reactions to the ground state and to excited states are calculated for the isotope chain of even-even Zirconium isotopes starting from stable nuclei up to beyond current experimental limits. Two-particle spectroscopic factors derived from Monte Carlo Shell Model calculations are used, together with the sequential description of the two-particle transfer reaction mechanism. The calculation shows a clear signature for a shape phase transition between Zr and Zr, which displays coexistence of a deformed ground state with an excited spherical state. Furthermore, we show that there is a qualitative difference with respect to the case of a normal shape phase transition that can be discriminated with two-neutron transfer reactions.

    Comments:
    4 figures, 1 table
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1905.12976 [pdf]
    PLB(2023)·8 citations
  3. 03

    [Submitted on 30 May 2019]

    Effects of an induced three-body force in the incident channel of (d,p) reactions

    M.J. Dinmore · N. K. Timofeyuk · J. S. Al-Khalili · R. C. Johnson

    A widely accepted practice for treating deuteron breakup in reactions relies on solving a three-body Schrödinger equation with pairwise -, - and - interactions. However, it was shown in [Phys. Rev. C \textbf{89}, 024605 (2014)] that projection of the many-body wave function into the three-body channel results in a complicated three-body operator that cannot be reduced to a sum of pairwise potentials. It contains explicit contributions from terms that include interactions between the neutron and proton via excitation of the target . Such terms are normally neglected. We estimate the first order contribution of these induced three-body terms and show that applying the adiabatic approximation to solving the model results in a simple modification of the two-body nucleon optical potentials. We illustrate the role of these terms for the case of Ca()Ca transfer reactions at incident deuteron energies of 11.8, 20 and 56 MeV, using several parameterisations of nonlocal optical potentials.

    Comments:
    7 pages, 2 figures. Publication due in Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1905.13071 [pdf]
    PRC(2019)·12 citations
  4. 04

    [Submitted on 29 May 2019]

    Towards Understanding Astrophysical Effects of Nuclear Symmetry Energy

    Bao-An Li🇺🇸 · Plamen G. Krastev🇺🇸 · De-Hua Wen🇨🇳 · Nai-Bo Zhang🇨🇳

    Determining the Equation of State (EOS) of dense neutron-rich nuclear matter is a shared goal of both nuclear physics and astrophysics. Except possible phase transitions, the density dependence of nuclear symmetry \esym is the most uncertain part of the EOS of neutron-rich nucleonic matter especially at supra-saturation densities. Much progresses have been made in recent years in predicting the symmetry energy and understanding why it is still very uncertain using various microscopic nuclear many-body theories and phenomenological models. Simultaneously, significant progresses have also been made in probing the symmetry energy in both terrestrial nuclear laboratories and astrophysical observatories. In light of the GW170817 event as well as ongoing or planned nuclear experiments and astrophysical observations probing the EOS of dense neutron-rich matter, we review recent progresses and identify new challenges to the best knowledge we have on several selected topics critical for understanding astrophysical effects of the nuclear symmetry energy.

    Comments:
    77 pages. Invited Review Article, EPJA (2019) in press
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Experiment (nucl-ex)
    arXiv:
    1905.13175 [pdf]
    EPJA(2019)·218 citations
  5. 05

    [Submitted on 30 May 2019]

    Possibility of Meson Condensation in Neutron Star: Unified Approach of Chiral SU(3) Model and QCD Sum Rules

    Shivam🇮🇳 · Arvind Kumar🇮🇳

    In the present work the conjunction of chiral SU(3) model with QCD sum rules is employed to explore the possibility of meson condensation in neutron stars. The quark and gluon condensates in terms of which the in-medium masses of mesons can be expressed are calculated using the chiral SU(3) model in the charge neutral matter which is relevant for neutron stars. It is observed that condition of meson condensation is satisfied for the density of about 7, where is the nuclear saturation density. In the end, a brief qualitative discussion of the magnetic field is also involved to check out for the further possibility of meson condensation.

    Comments:
    21 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1905.13184 [pdf]
    Eur.Phys.J.Plus(2019)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE