ABSTRACT We report a new equation of state (EoS) of cold and hot hyperonic matter constructed in the framework of the quark–mesoncoupling (QMCA) model. The QMCA EoS yields results compatible with available nuclear physics constraints and astrophysical observations. It covers the range of temperatures from T = 0 to 100 MeV, entropies per particle S/A between 0 and 6, lepton fractions from YL = 0.0 to 0.6, and baryon number densities nB = 0.05–1.2 fm−3. Applications of the QMCA EoS are made to cold neutron stars (NSs) and to hot protoneutron stars (PNSs) in two scenarios: (i) leptonrich matter with trapped neutrinos (PNSI) and (ii) deleptonizedmore »
Limiting masses and radii of neutron stars and their implications
We combine equation of state of dense matter up to twice nuclear saturation density (nsat =
0.16 fm−3
) obtained using chiral effective field theory (χEFT), and recent observations of neutron
stars to gain insights about the highdensity matter encountered in their cores. A key element in
our study is the recent Bayesian analysis of correlated EFT truncation errors based on orderbyorder calculations up to nexttonexttonexttoleading order in the χEFT expansion. We refine the
bounds on the maximum mass imposed by causality at high densities, and provide stringent limits
on the maximum and minimum radii of ∼ 1.4 M and ∼ 2.0 M stars. Including χEFT predictions
from nsat to 2 nsat reduces the permitted ranges of the radius of a 1.4 M star, R1.4, by ∼ 3.5 km.
If observations indicate R1.4 < 11.2 km, our study implies that either the squared speed of sound
c
2
s > 1/2 for densities above 2 nsat, or that χEFT breaks down below 2 nsat. We also comment
on the nature of the secondary compact object in GW190814 with mass ' 2.6 M, and discuss
the implications of massive neutron stars > 2.1 M (2.6 M) in future radio and gravitationalwave
searches. Some form of strongly interacting matter with c
2
s > 0.35 (0.55) must be more »
 Award ID(s):
 1927130
 Publication Date:
 NSFPAR ID:
 10194465
 Journal Name:
 ArXivorg
 ISSN:
 23318422
 Sponsoring Org:
 National Science Foundation
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