https://doi.org/10.1140/epjc/s10052-024-13236-0
Regular Article - Theoretical Physics
MURCA driven bulk viscosity in neutrino trapped baryonic matter
1
Mukesh Patel School of Technology Management and Engineering, SVKM’s NMIMS University, Vile Parle (W), 400056, Mumbai, India
2
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence, 201314, Greater Noida, Uttar Pradesh, India
Received:
24
January
2024
Accepted:
13
August
2024
Published online:
5
September
2024
We examine bulk viscosity, taking into account trapped neutrinos in baryonic matter, in the context of binary neutron star mergers. Following the merging event, the binary star can yield a remnant compact object with densities up to 5 nuclear saturation density and temperature up to 50 MeV resulting in the retention of neutrinos. We employ two relativistic mean field models, NL3 and DDME2, to describe the neutrino-trapped baryonic matter. The dissipation coefficient is determined by evaluating the Modified URCA interaction rate in the dense baryonic medium, and accounting for perturbations caused by density oscillations. We observe the resonant behavior of bulk viscosity as it varies with the temperature of the medium. The bulk viscosity peak remains within the temperature range of 
–50 MeV, depending upon the underlying equation of states and lepton fractions. This temperature range corresponds to the relevant domain of binary neutron star mergers. We also note that in presence of neutrinos in the medium the bulk viscosity peak shifts towards higher temperature and the peak value of bulk viscosity also changes. The time scale of viscous dissipation is dictated by the beta-off-equilibrium susceptibilities derived from the nuclear equation of state. The resulting viscous decay time scale ranges from 32–100 ms, which aligns with the order of magnitude of the post-merger object’s survival time in some specific scenarios.
© The Author(s) 2024
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Funded by SCOAP3.
