MSc Thesis Defence - Unveiling the Neutrino Dynamics in Pre-Core Collapse Supernovae

MSc Candidate

Yash Bhat

Abstract

Core-collapse supernovae represent one of the most energetic events in the universe, where neutrino interactions play a crucial role in the explosion mechanism, as neutrinos are the main mechanism of energy loss in core-collapse supernovae. Due to their minimal interaction with ordinary matter, neutrinos can escape the core, carrying away energy and accelerating the collapse, which occurs within milliseconds. Neutrino production, however, is prominent even during the stages before the star's core collapse. This work investigates neutrino transport through the dense nucleonic matter of stellar cores before they undergo core collapse, namely the Pre Core Collapse Supernova (Pre-CCSN) stage. Using the one-dimensional stellar evolution code MESA, we simulate the core-collapse and Pre-CCSN stages, and process and analyze neutrino interactions under extreme densities. The study employs the virial expansion to account for interparticle correlations in the sub-nuclear density regime - effects not typically included in standard stellar evolution codes. By computing structure factor corrections to neutrino-nucleon scattering cross sections, this work provides improved estimates of neutrino-nucleon neutral current scattering cross sections and neutrino opacities. The results offer insights into neutrino transport before stellar collapse and contribute to our understanding of supernova dynamics.

Examination Committee

• Dr. Eric Poisson, Chair
• Dr. Liliana Caballero, Advisor
• Dr. Paul Garrett, Advisory Committee
• Dr. Ralf Gellert, Advisory Committee