Speaker: Steven Harris( Indiana University Bloomington)

Title: Bulk viscosity from neutron light and dark decays

Abstract: In a violent event like the merger of two neutron stars, the nuclear matter is compressed and uncompressed, causing it to depart from chemical equilibrium.  Weak interactions like the Urca process work to reestablish equilibrium, which can lead to bulk viscous energy dissipation.  Flavor equilibration is beginning to be included in numerical simulations of neutron star mergers.  Here on Earth, the lifetime of the neutron is under some dispute, with some raising the possibility of an additional "dark" decay channel of the neutron.  I will discuss the bulk viscosity ensuing from the Urca neutron decays, and then how an additional neutron decay channel can modify the viscous dissipation in neutron star merger environments.