Supernova Neutrinos: flavour conversion mechanisms and new physics scenarios

A core-collapse supernova (SN) releases almost all of its energy in the form of neutrinos, which provide a unique opportunity to probe the working machinery of a SN. These sites are prone to neutrino-neutrino refractive effects, which can lead to fascinating collective flavour oscillations among neutrinos. This causes rapid neutrino flavour conversions deep inside the SN even for suppressed mixing angles, with intriguing consequences for the explosion mechanism as well as nucleosynthesis. We review the physics of collective oscillations of neutrinos -- both slow and fast, along with the well-known resonant flavour conversion effects, and discuss the current state-of-the-art of the field. Furthermore, we discuss how neutrinos from a SN can be used to probe novel particle physics properties, extreme values of which are otherwise inaccessible in laboratories.