Towards generating a new supernova equation of state: A systematic analysis of cold hybrid stars

摘要

The hadron-quark phase transition in core-collapse supernovae (CCSNe) has thepotential to trigger explosions in otherwise nonexploding models. However,those hybrid supernova equations of state (EOS) shown to trigger an explosiondo not support the observational 2 M$_\odot$ neutron star maximum massconstraint. In this work, we analyze cold hybrid stars by the means of asystematic parameter scan for the phase transition properties, with the aim todevelop a new hybrid supernova EOS. The hadronic phase is described with thestate-of-the-art supernova EOS HS(DD2), and quark matter by an EOS with aconstant speed of sound (CSS) of $c_{QM}^2=1/3$. We find promising cases whichmeet the 2 M$_\odot$ criterion and are interesting for CCSN explosions. We showthat the very simple CSS EOS is transferable into the well-known thermodynamicbag model, important for future application in CCSN simulations. In the secondpart, the occurrence of reconfinement and multiple phase transitions isdiscussed. In the last part, the influence of hyperons in our parameter scan isstudied. Including hyperons no change in the general behavior is found, exceptfor overall lower maximum masses. In both cases (with and without hyperons) wefind that quark matter with $c_{QM}^2=1/3$ can increase the maximum mass onlyif reconfinement is suppressed or if quark matter is absolutely stable.