Ruling out the supersoft high-density symmetry energy from the discovery of PSR J0740+6620 with mass $2.14_{-0.09}^{+0.10}{M}_{\odot }$

Abstract

Using the very recently reported mass $2.14_{-0.09}^{+0.10}{M}_{\odot }$ of PSR J0740+6620 together with the data of finite nuclei and the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, we show that the symmetry energy $E_{\mathrm{sym}}(n)$ cannot be supersoft so that it becomes negative at suprasaturation densities in neutron stars (NSs) and thus may make the NS have a pure neutron matter core. This is in contrast to the fact that using the mass $2.01\pm 0.04M_{\odot }$ of PSR J0348+0432 as the NS maximum mass cannot rule out the supersoft high-density $E_{\mathrm{sym}}(n)$. Furthermore, we find the stiffer high-density $E_{\mathrm{sym}}(n)$ based on the existence of $2.14M_{\odot }$ NSs leads to a strong constraint of ${\Lambda }_{1.4}\ge 348_{-51}^{+88}$ for the dimensionless tidal deformability of the canonical $1.4M_{\odot }$ NS.

Comments: 8 pages, 2 figures, 1 table. The updated 2.14 solar mass used, results updated and presentation improved. Accepted version to appear in ApJ