Regular Article - Theoretical Physics
Delta-resonances and hyperons in proto-neutron stars and merger remnants
Frankfurt Institute for Advanced Studies, Ruth-Moufang str. 1, 60438, Frankfurt am Main, Germany
2 Institute of Theoretical Physics, University of Wrocław, pl. M. Borna 9, 50-204, Wrocław, Poland
3 Byurakan Astrophysical Observatory, 0213, Byurakan, Armenia
4 Department of Physics, Yerevan State University, 0025, Yerevan, Armenia
Accepted: 7 July 2022
Published online: 26 July 2022
The equation of state (EoS) and composition of dense and hot -resonance admixed hypernuclear matter is studied under conditions that are characteristic of neutron star binary merger remnants and supernovas. The cold, neutrino free regime is also considered as a reference for the astrophysical constraints on the EoS of dense matter. Our formalism uses the covariant density functional (CDF) theory successfully adapted to include the full baryon octet and non-strange members of decouplet with density-dependent couplings that have been suitably adjusted to the existing laboratory and astrophysical data. The effect of -resonances at finite temperatures is to soften the EoS of hypernuclear matter at intermediate densities and stiffen it at high densities. At low temperatures, the heavy baryons , , , and appear in the given order if the -meson couplings are close to those for the nucleon-meson couplings. As is the case for hyperons, the thresholds of -resonances move to lower densities with the increase of temperature indicating a significant fraction of ’s in the low-density subnuclear regime. We find that the -resonances comprise a significant fraction of baryonic matter, of the order of at temperatures of the order of several tens of MeV in the neutrino-trapped regime and, thus, may affect the supernova and binary neutron star dynamics by providing, for example, a new source for neutrino opacity or a new channel for bulk viscosity via the direct Urca processes. The mass-radius relation of isentropic static, spherically symmetric hot compact stars is discussed.
© The Author(s) 2022
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