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Nuclear Theory·nucl-th

Thursday·August 1, 2019

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 31 Jul 2019]

    Effects of the equation of state on the bulk properties of maximally-rotating neutron stars

    P.S. Koliogiannis · Ch.C. Moustakidis

    Neutron stars are among the densest known objects in the universe and an ideal laboratory for the strange physics of super-condensed matter. While the simultaneously measurements of mass and radius of non-rotating neutron stars may impose constraints on the properties of the dense nuclear matter, the observation and study of maximally-rotating ones, close to the mass-shedding limit, may lead to significantly further constraints. Theoretical predictions allow neutron stars to rotate extremely fast (even more than ). However, until this moment, the fastest observed rotating pulsar has a frequency of , much lower compared to the theoretical predictions. There are many suggestions for the mechanism which lead to this situation. In any case, the theoretical study of uniformly rotating neutron stars, along with the accurate measurements, may offer rich information concerning the high density part of the equation of state. In addition, neutron stars through their evolution, may provide us with a criteria to determine the final fate of a rotating compact star. Sensitivity of bulk neutron stars properties on the equation of state at the mass-shedding limit are the main subject of the present study.

    Comments:
    v1: 16 pages, 24 figures. v2: 18 pages, 14 labeled figures, 5 tables, sections and references had been updated, accepted for publication in Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
    arXiv:
    1907.13375 [pdf]
    PRC(2020)·63 citations
  2. 02

    [Submitted on 30 Jul 2019]

    Relativistic Feynman-Metropolis-Teller Equation of State for White Dwarfs in presence of Magnetic Field

    Sujan Kumar Roy · Somnath Mukhopadhyay · Joydev Lahiri · D.N. Basu

    The relativistic Feynman-Metropolis-Teller treatment of compressed atoms is extended to treat magnetized matter. Each atomic configuration is confined by a Wigner-Seitz cell and is characterized by a positive electron Fermi energy which varies insignificantly with the magnetic field. In the relativistic treatment the limiting configuration is reached when the Wigner-Seitz cell radius equals the radius of the nucleus with a maximum value of the electron Fermi energy which can not be attained in presence of magnetic field due to the effect of Landau quantization of electrons within the Wigner-Seitz cell. This treatment is implemented to develop the Equation of State for magnetized White Dwarf stars in presence of Coulomb screening. The mass-radius relations for magnetized White Dwarfs are obtained by solving the general relativistic hydrostatic equilibrium equations using Schwarzschild metric description suitable for non rotating and slowly rotating stars. The explicit effects of the magnetic energy density and pressure contributed by a density-dependent magnetic field are included to find the stable configurations of magnetized Super-Chandrasekhar White Dwarfs.

    Comments:
    11 pages including 12 figures and 1 table. arXiv admin note: text overlap with arXiv:1507.05439
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1907.13480 [pdf]
    PRD(2019)·16 citations
  3. 03

    [Submitted on 31 Jul 2019]

    Heavy isotope production in collisions at MeV

    S. Ayik🇺🇸 · O. Yilmaz🇹🇷 · B. Yilmaz🇹🇷 · A. S. Umar🇺🇸

    Employing the quantal diffusion mechanism for multi-nucleon transfer, the double differential cross-sections are calculated for production of primary projectile-like and target-like fragments in collisions of system at MeV. Including de-excitation due to neutron emission, the cross-section for production of , and isotopes are estimated and compared with data.

    Comments:
    7 pages, 3 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1907.13521 [pdf]
    PRC(2019)·29 citations
  4. 04

    [Submitted on 30 Jul 2019] (cross-list from astro-ph.SR)

    Uncertainties in p-process nucleosynthesis from Monte Carlo variation of reaction rates

    N. Nishimura · T. Rauscher · R. Hirschi · G. Cescutti · A. St. J. Murphy · C. Fröhlich

    It has been suggested that a p process can occur when hot, dense, and proton-rich matter is expanding within a strong flux of anti-neutrinos. In such an environment, proton-rich nuclides can be produced in sequences of proton captures and (n,p) reactions, where the free neutrons are created in situ by reactions. The detailed hydrodynamic evolution determines where the nucleosynthesis path turns off from N = Z line and how far up the nuclear chart it runs. In this work, the uncertainties on the final isotopic abundances stemming from uncertainties in the nuclear reaction rates were investigated in a large-scale Monte Carlo approach, simultaneously varying ten thousand reactions. A large range of model conditions was investigated because a definitive astrophysical site for the p process has not yet been identified. The present parameter study provides, for each model, identification of the key nuclear reactions dominating the uncertainty for a given nuclide abundance. As all rates appearing in the p process involve unstable nuclei, and thus only theoretical rates are available, the final abundance uncertainties are larger than those for nucleosynthesis processes closer to stability. Nevertheless, most uncertainties remain below a factor of three in trajectories with robust nucleosynthesis. More extreme conditions allow production of heavier nuclides but show larger uncertainties because of the accumulation of the uncertainties in many rates and because the termination of nucleosynthesis is not at equilibrium conditions. It is also found that the solar ratio of the abundances of Mo and Mo could be reproduced within uncertainties.

    Comments:
    19 pages, 12 figures, 8 tables, accepted for publication in MNRAS
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1907.13129 [pdf]
    MNRAS(2019)·35 citations
  5. 05

    [Submitted on 30 Jul 2019] (cross-list from hep-th)

    Coupling Constant Corrections in a Holographic Model of Heavy Ion Collisions with Nonzero Baryon Number Density

    Åsmund Folkestad🇺🇸 · Sašo Grozdanov🇺🇸 · Krishna Rajagopal🇺🇸 · Wilke van der Schee🇳🇱

    Sufficiently energetic collisions of heavy ions result in the formation of a droplet of a strongly coupled liquid state of QCD matter known as quark-gluon plasma. By using gauge-gravity duality (holography), a model of a rapidly hydrodynamizing and thermalizing process like this can be constructed by colliding sheets of energy density moving at the speed of light and tracking the subsequent evolution. In this work, we consider the dual gravitational description of such collisions in the most general bulk theory with a four-derivative gravitational action containing a dynamical metric and a gauge field in five dimensions. Introducing the bulk gauge field enables the analysis of collisions of sheets which carry nonzero "baryon" number density in addition to energy density. Introducing the four-derivative terms enables consideration of such collisions in a gauge theory with finite gauge coupling, working perturbatively in the inverse coupling. While the dynamics of energy and momentum in the presence of perturbative inverse-coupling corrections has been analyzed previously, here we are able to determine the effect of such finite coupling corrections on the dynamics of the density of a conserved global charge, which we take as a model for the dynamics of nonzero baryon number density. In accordance with expectations, as the coupling is reduced we observe that after the collisions less baryon density ends up stopped at mid-rapidity and more of it ends up moving near the lightcone.

    Comments:
    v2: 40 pages, 12 figures. Minor adjustments. Version appearing in JHEP
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1907.13134 [pdf]
    JHEP(2019)·16 citations
  6. 06

    [Submitted on 30 Jul 2019] (cross-list from hep-ph)

    Global parameterization of scattering up to 2 GeV

    J.R. Pelaez🇪🇸 · A. Rodas🇪🇸 · J. Ruiz de Elvira🇨🇭

    We provide global parameterizations of scattering and partial waves up to roughly 2 GeV for phenomenological use. These parameterizations describe the output and uncertainties of previous partial-wave dispersive analyses of , both in the real axis up to 1.12 GeV and in the complex plane within their applicability region, while also fulfilling forward dispersion relations up to 1.43 GeV. Above that energy we just describe the available experimental data. Moreover, the analytic continuations of these global parameterizations also describe accurately the dispersive determinations of the , and pole parameters.

    Comments:
    18 pages, 8 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1907.13162 [pdf]
    EPJC(2019)·75 citations
  7. 07

    [Submitted on 30 Jul 2019] (cross-list from hep-ph)

    Summary of the NuSTEC Workshop on Shallow- and Deep-Inelastic Scattering

    C. Andreopoulos🇬🇧 · M. Sajjad Athar🇮🇳 · C. Bronner🇯🇵 · S. Dytman🇺🇸 · K. Gallmeister🇩🇪 · H. Haider🇮🇳 · N. Jachowicz🇧🇪 · M. Kabirnezhad🇬🇧 · T. Katori🇬🇧 · S. Kulagin🇷🇺 · A. Kusina🇵🇱 · M. Muether🇺🇸 and 5 other authors

    The NuSTEC workshop (https://indico.cern.ch/event/727283) held at L'Aquila in October 2018 was devoted to neutrino-nucleus scattering in the kinematic region where hadronic systems with invariant masses above the resonance are produced: the so-called shallow- and deep-inelastic scattering regime. Not only is the physics in this kinematic region quite intriguing, it is also important for current and future oscillation experiments with accelerator and atmospheric neutrinos. For the benefit of the community, links to the presentations are accompanied by annotations from the speakers.

    Comments:
    Proceedings of "NuSTEC workshop of Neutrino-Nucleus Scattering in the Shallow- and Deep-Inelastic Kinematic regime", GSSI, L'Aquila, Italy on October 11-13, 2018. 31 pages, 24 talk links
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1907.13252 [pdf]
    20 citations

Affiliations

first authorsco-authorsvia INSPIRE