Bulk viscosity from neutron decays in dense matter

ORAL

Abstract

When the dense matter inside neutron stars is compressed, it is pushed out of chemical equilibrium. To reestablish equilibrium, neutron decays and their inverses occur, resulting in bulk-viscous energy dissipation. In standard npe matter, the bulk viscosity due to the Urca process leads to bulk viscosity with one resonant peak as a function of temperature. I will discuss how the value of bulk viscosity at the peak is related to the symmetry energy as well as the possibility of a second peak in the bulk viscosity at higher temperature due to neutron decay into dark baryons.

*I acknowledge the support of the National Science Foundation grant PHY 21-16686.

Publication: https://arxiv.org/abs/2509.25838
https://arxiv.org/abs/2505.12133

Presenters

  • Steven P Harris

    • Iowa State University

Authors

  • Steven P Harris

    • Iowa State University
  • Charles J Horowitz

    • Indiana University Bloomington