NBIA Seminar: Meng-Ru Wu

Neutrino flavor transformation in neutrino-dense astrophysical environments

Neutrino flavor oscillations observed by various experiments have led to the understanding that neutrinos are massive and their vacuum mass eigenstates are distinct from the flavor states. However, in hot and dense astrophysical environments such as core-collapse supernovae and mergers of binary neutron stars, where neutrino number densities are comparable to or larger than matter number density, rich phenomena of neutrino flavor transformation can happen very differently from vacuum oscillations and the Mikheyev-Smirnov-Wolfenstein effect in matter, due to the non-linear couplings among neutrinos. Such flavor transformation can happen in the deep interior of the astrophysical events and thus can potentially affect the dynamics of the system, the nucleosynthesis outcome, and the expected neutrino signals. In this talk, I will discuss different features of flavor transformation behaviors in these neutrino-dense astrophysical environments, the possible implications, and future challenges.