2021/07/31 by R. C. Essick, Reed Essick, Philippe Landry +3
Physics and Astronomy · #Computer science #Cosmology and Gravitation Theories #Neutron #Nuclear physics #Nuclear physics research studies #Physics #Pulsars and Gravitational Waves Research #astro-ph.HE #nucl-ex #nucl-th
paper · pdf · doi:10.1103/physrevc.104.065804
published as Phys. Rev. C 104, 065804 (2021) · 18 pages, 12 figures, 1 table
arxiv created 2021/12/15 · openalex publication_date 2021/12/15 · arxiv updated 2021/12/16 · openalex created_date 2021/12/31 · openalex updated_date 2026/08/06
The symmetry energy and its density dependence are pivotal 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 0.283\ifmmode±\else\textpm\fi0.071 fm for the neutron-skin thickness of 208Pb, Rskin^208Pb, implying a symmetry-energy slope parameter L of 106\ifmmode±\else\textpm\fi37 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 S0, L, and Rskin^208Pb directly from observations of neutron stars with minimal modeling assumptions. The resulting astrophysical constraints from heavy pulsar masses, LIGO/Virgo, and NICER favor smaller values of the neutron skin and L, as well as negative symmetry incompressibilities. Combining astrophysical data with chiral effective field theory (\ensuremathχEFT) and PREX-II constraints yields S0=33.0_\ensuremath-1.8+2.0 MeV, L=53_\ensuremath-15+14 MeV, and Rskin^208Pb=0.17_\ensuremath-0.04+0.04 fm. We also examine the consistency of several individual \ensuremathχEFT calculations with astrophysical observations and terrestrial experiments. We find that there is only mild tension between \ensuremathχEFT, astrophysical data, and PREX-II's Rskin^208Pb measurement (p value =12.3%) and that there is excellent agreement between \ensuremathχEFT, astrophysical data, and other nuclear experiments.