Arxiv:2107.01879V2 [Nucl-Th] 22 Jul 2021 Wgpaeng@Clunix.Com § Mannque.Rho@Ipht.Fr J = (38.1 ± 4.7) Mev,L = (106 ± 37) Mev
Cusp in the Symmetry Energy, PREX-II And Pseudo-Conformal Sound Speed in Neutron Stars Hyun Kyu Lee,1, ∗ Yong-Liang Ma,2, 3, y Won-Gi Paeng,4, z and Mannque Rho5, x 1Department of Physics, Hanyang University, Seoul 133-791, Korea 2School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, 310024, China 3International Center for Theoretical Physics Asia-Pacific (ICTP-AP) (Beijing/Hangzhou), UCAS, Beijing 100190, China 4A I Lab., Clunix, Seoul 07209, Korea 5Institut de Physique Th´eorique,Universit´eParis-Saclay, CNRS, CEA, 91191, Gif-sur-Yvette, France (Dated: July 23, 2021) The recent announcement of the PREX-II measurement of the neutron skin of 208Pb that suggests a stiff symmetry energy near nuclear matter density n0 and its impact on the EoS of massive compact stars raise the issue as to whether the widely accepted lore in nuclear astrophysics that the EoS determined at n0 necessarily gives a stringent \constraint" at high densities relevant to massive compact stars. We present the argument that the \cusp" structure in the symmetry energy at n1=2 >∼ 2n0 predicted by a topology change in dense matter could obstruct the validity of the lore. The topology change, encoding the emergence of QCD degrees of freedom in terms of hidden local and scale symmetries, predicts an EoS that is soft below and stiff above n >∼ n1=2, involving no low-order phase transitions, and yields the macrophysical properties of neutron stars overall consistent with the astrophysical observations including the maximum mass 2:0 <∼ M=M <∼ 2:2 as well as the GW data.
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