Bulk viscosity from neutron decays to dark sector particles in neutron star merger conditions*

A disagreement between the results of two experiments measuring the neutron lifetime has lead to the hypothesis that, in vacuum, the neutron decays into dark sector particles a small percentage of the time. Considering a model where the neutron can decay into a heavy dark baryon and a light scalar, we examine the impact of these particles on transport in neutron star mergers. Traditional neutron decays (that is, the Urca process) help to reestablish chemical equilibrium when the neutron star matter is compressed, leading to energy dissipation from bulk viscosity. I will discuss how an additional neutron decay channel alters the traditional picture of the bulk viscosity in neutron star merger conditions.