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Nuclear Theory·nucl-th

Monday·February 22, 2021

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 19 Feb 2021]

    Dynamical Screening Effects on Big Bang Nucleosynthesis

    Eunseok Hwang🇰🇷 · Dukjae Jang🇰🇷 · Kiwan Park🇰🇷 · Motohiko Kusakabe🇨🇳 · Toshitaka Kajino🇨🇳 · A. Baha Balantekin🇯🇵 · Tomoyuki Maruyama🇯🇵 · Chang-Mo Ryu🇰🇷 · Myung-Ki Cheoun🇰🇷

    A moving ion in plasma creates a deformed electric potential depending on the ion velocity, which leads to the distinct screening effect compared to the standard static Salpeter formula. In this paper, adopting the test charge method, we explore the dynamical screening effects on big bang nucleosynthesis (BBN). We find that the high temperature in the early universe causes the ion velocity to be faster than the solar condition so that the electric potential is effectively polarized. However, the low density of background plasma components significantly suppresses the dynamical screening effects on thermonuclear reaction rates during the BBN epoch. We compare our results with several thermonuclear reaction rates for solar fusion considering the dynamical screening effects. Also, we discuss the additional plasma properties in other astrophysical sites for the possible expansion from the present calculation in the future.

    Subjects:
    Nuclear Theory (nucl-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
    arXiv:
    2102.09801 [pdf]
    JCAP(2021)·13 citations
  2. 02

    [Submitted on 19 Feb 2021]

    Comprehensive investigation of the symmetric space-star configuration in the nucleon-deuteron breakup

    H. Witala · J. Golak · R. Skibinski · K. Topolnicki · E. Epelbaum · H. Krebs · P. Reinert

    We examine a description of available cross section data for symmetric space star (SST) configurations in the neutron-deuteron (nd) and proton-deuteron (pd) breakup reaction using numerically exact solutions of the three-nucleon (3N) Faddeev equation based on two- and three-nucleon (semi)phenomenological and chiral forces. The predicted SST cross sections are very stable with respect to the underlying dynamics for incoming nucleon laboratory energies below MeV. We discuss possible origins of the surprising discrepancies between theory and data found in low-energy nd and pd SST breakup measurements.

    Comments:
    30 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2102.09863 [pdf]
    PRC(2021)·12 citations
  3. 03

    [Submitted on 19 Feb 2021]

    Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of Pb with Minimal Modeling Assumptions

    Reed Essick · Ingo Tews · Philippe Landry · Achim Schwenk

    The symmetry energy and its density dependence are crucial inputs for many nuclear physics and astrophysics applications, as they determine properties ranging from the neutron-skin thickness of nuclei to the crust thickness and the radius of neutron stars. Recently, PREX-II reported a value of fm for the neutron-skin thickness of Pb, implying a slope parameter MeV, larger than most ranges obtained from microscopic calculations and other nuclear experiments. We use a nonparametric equation of state representation based on Gaussian processes to constrain the symmetry energy , , and directly from observations of neutron stars with minimal modeling assumptions. The resulting astrophysical constraints from heavy pulsar masses, LIGO/Virgo, and NICER clearly favor smaller values of the neutron skin and , as well as negative symmetry incompressibilities. Combining astrophysical data with PREX-II and chiral effective field theory constraints yields MeV, MeV, and fm.

    Comments:
    11 pages, 6 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
    arXiv:
    2102.10074 [pdf]
    PRL(2021)·225 citations

Affiliations

first authorsco-authorsvia INSPIRE