A Unified Approach to Urca Processes

Weak decay processes (like direct and modified Urca) play an important role in transport phenomena in neutron stars and neutron star mergers. The traditional treatment for the in-medium nucleon propagator in the modified Urca process uses crude approximations. We are developing an approach to unify direct and modified Urca processes by including the nucleon widths. This potentially allows us to improve several aspects of the Urca rates, which can influence cooling, bulk viscosity and other dissipative processes.