Neutrinos from Protoneutron Stars: a Probe of Hot and Dense Matter Sanjay Reddy and Madappa Prakash

Neutrino processes in dense matter play a key role in the dynamics, deleptonization and the early cooling of hot protoneutron stars formed in the gravitational collapse of massive stars. Here we calculate neutrino mean free paths from neutrino-hyperon interactions in dense matter containing hyperons. Significant contributions to the neutrino opacity arise from scattering involving the Σ− hyperon, and absorption processes involving the neutral and Σ− hyperons. The estimates given here emphasize the need for (a) opacities which incorporate many-body effects in a multi-component mixture, and (b) new calculations of thermal and leptonic evolution of protoneutron stars with neutrino transport and equations of state with strangeness-rich matter.