Strangeness-changing Rates and Hyperonic Bulk Viscosity in Neutron Star Mergers

Understand

In this paper we present a computation of the rates of strangeness-changing processes and the resultant bulk viscosity in matter at the densities and temperatures typical of neutron star mergers.

• To deal with the high temperature in this environment we go beyond the Fermi surface approximation in our rate calculations and numerically evaluate the full phase space integral.
• We include processes where quarks move between baryons via meson exchange: these have generally been omitted in previous analyses but provide the dominant contribution to the rates of strangeness-changing processes and the bulk viscosity.
• The calculation of these rates is an essential step towards any calculation of dissipation mechanisms in hyperonic matter in mergers.