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Nuclear Theory·nucl-th

Thursday·November 24, 2022

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 01

    [Submitted on 22 Nov 2022]

    Special point "trains" in the M-R diagram of hybrid stars

    David Blaschke🇵🇱 · Alexander Ayriyan🇦🇲 · Mateusz Cierniak🇵🇱 · Ana Gabriela Grunfeld🇦🇷 · Oleksii Ivanytskyi🇵🇱 · Mahboubeh Shahrbaf🇵🇱

    We present a systematic investigation of the possible locations for the special point (SP), a unique feature of hybrid neutron stars in the mass-radius diagram. The study is performed within the two-phase approach where the high-density (quark matter) phase is described by the covariant nonlocal Nambu--Jona-Lasinio (nlNJL) model equation of state (EOS) which is shown to be equivalent to a constant-sound-speed (CSS) EOS. For the nuclear matter phase around saturation density different relativistic density functional EOSs are used: DD2p00, its excluded-volume modification DD2p40 and the hypernuclear EOS DD2Y-T. In the present contribution we apply the Maxwell construction scheme for the deconfinement transition and demonstrate that a simultaneous variation of the vector and diquark coupling constants results in the occurrence of SP "trains" which are invariant against changing the nuclear matter EOS. We propose that the SP train corresponding to a variation of the diquark coupling at constant vector coupling is special since it serves as a lower bound for the line of maximum masses and accessible radii of massive hybrid stars.

    Comments:
    8 pages, 5 figures, Contribution to Proceedings of Quark Confinement and the Hadron Spectrum XV, August 1-6, 2022, Stavanger, Norway
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2211.12626 [pdf]
    EPJ Web Conf.(2022)·3 citations
  2. 02

    [Submitted on 23 Nov 2022]

    Probing the size and binding energy of the hypertriton in heavy ion collisions

    C.A. Bertulani🇺🇸

    The hypertriton is predicted to have a small binding energy (a weighted average of about 150 keV), consistent with a large matter radius (~ 10 fm), larger than the historical 11Li halo discovered more than 35 years ago. But the reported experimental values of the binding energy of the hypertriton range from 70 to 400 keV. In this work I discuss the electromagnetic response and interaction radius of the hypertriton and how high energy heavy ion collisions (~ 1 - 2 GeV/nucleon) can help achieving a higher accuracy for the determination of its size and binding energy.

    Comments:
    8 pages, 10 figures, Phys. Lett B, accepted
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    2211.12643 [pdf]
    PLB(2023)·12 citations
  3. 03

    [Submitted on 23 Nov 2022]

    Early deconfinement of asymptotically conformal color-superconducting quark matter in neutron stars

    Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱 · Tobias Fischer🇵🇱 · Andreas Bauswein🇩🇪

    We present a relativistic density functional approach to color superconducting quark matter that mimics quark confinement by a fast growth of the quasiparticle selfenergy in the confining region. The approach is shown to be equivalent to a chiral model of quark matter with medium dependent couplings. While the (pseudo)scalar sector of the model is fitted to the vacuum phenomenology of quantum chromodynamics, the strength of interaction in the vector and diquark channels is varied in order to provide the best agreement with the observational constraints on the mass-radius relation and tidal deformability of neutron stars modelled with our approach. In order to recover the conformal behavior of quark matter at asymptotically high densities we introduce a medium dependence of the vector and diquark couplings motivated by the nonperturbative gluon exchange. Our analysis signals that the onset of deconfinement to color superconducting quark matter is likely to occur in neutron stars with masses below 1.0 .

    Comments:
    8 pages, 4 figuures, Contribution to Proceedings of Quark Confinement and the Hadron Spectrum XV, August 1-6, 2022, Stavanger, Norway
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2211.12730 [pdf]
    EPJ Web Conf.(2022)·2 citations
  4. 04

    [Submitted on 23 Nov 2022]

    Radial Oscillations of Dark Matter admixed Neutron Stars

    Pinku Routray · H. C. Das · Souhardya Sen · Bharat Kumar · Grigoris Panotopoulos · Tianqi Zhao

    Within the relativistic mean-field model, we investigate the properties of dark matter (DM) admixed neutron stars, considering non-rotating objects made of isotropic matter. We adopt the IOPB-I hadronic equation of state (EOS) by assuming that the fermionic DM within super-symmetric models has already been accreted inside the neutron star (NS). The impact of DM on the mass-radius relationships and the radial oscillations of pulsating DM admixed neutron stars (with and without the crust) are explored. It is observed that the presence of DM softens the EOS, which in turn lowers the maximum mass and its corresponding radius. Moreover, adding DM results in higher frequencies of pulsating objects and hence we show the linearity of fundamental mode frequency of canonical NS with DM Fermi momentum. We also investigate the profile of eigenfunctions solving the Sturm-Liouville boundary value problem, and verify its validity. Further, we study the stability of NSs considering the fundamental mode frequency variation with the mass of the star, and verify the stability criterion . Finally, the effect of the crust on the large frequency separation for different DM Fermi momenta is shown as well.

    Comments:
    Published in Phys. Rev. D 107, 103039 (2023)
    Subjects:
    Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc)
    arXiv:
    2211.12808 [pdf]
    PRD(2023)·50 citations

Affiliations

first authorsco-authorsvia INSPIRE