Impact of Quarks and Pions on Dynamics and Neutrino Signal of Black Hole Formation in Non-rotating Stellar Core Collapse

TL;DR

This study numerically investigates how quarks and pions influence the dynamics, neutrino emission, and observable signals during black hole formation from stellar core collapse, highlighting their effects on neutrino luminosity and temperature evolution.

Contribution

It is the first detailed simulation incorporating quarks and pions into black hole formation models, assessing their impact on neutrino signals and core dynamics.

Findings

Quarks and pions shorten neutrino emission duration.

Pions increase neutrino luminosity and energy before black hole formation.

Neutrino signals are detectable and affected by quark and pion emergence.

Abstract

In the formation process of black holes, the density and temperature of matter become sufficiently high for quarks and pions to appear. In this study we numerically investigate stellar core collapse and black hole formation taking into account the equations of state involving quarks and/or pions. In our simulations, we utilize a code that solves the general relativistic hydrodynamics and neutrino transfer equations simultaneously, treating neutrino reactions in detail under spherical symmetry. Initial models with three different masses, namely, 40, 100 and 375Msolar, are adopted. Our results show that quarks and pions shorten the duration of neutrino emission if the collapse bounces before black hole formation. In addition, pions increase the luminosity and average energy of neutrinos before black hole formation. We also find that the hadron-quark phase transition leads to an interesting evolution of temperature. Moreover, the neutrino event number is evaluated for the currently operating neutrino detector, SuperKamiokande, to confirm that it is not only detectable but also affected by the emergence of quarks and pions for Galactic events. While there are some issues, such as hyperons, beyond the scope of this study, this is the first serious attempt to assess the impact of quarks and pions in dynamical simulations of black hole formation and will serve as an important foundation for future studies.