IFIC Seminar: Supernovae as probes of soft lepton number violation

por Manibrata Sen (Max-Planck-Institut für Kernphysik Heidelberg)

martes 29 mar. 2022 12:00 → 13:00 Europe/Madrid

Primera-1-1-1 - Paterna. Seminario (IFIC)

Ever since the discovery of neutrinos, we have wondered if neutrinos are their own antiparticles, and whether lepton number is violated or not. One remarkable possibility is that lepton-number violation in the Standard Model is soft. In such scenarios, neutrinos have a pseudo-Dirac nature, with a tiny mass difference between active and sterile states, having oscillations driven by this tiny mass difference. Such oscillations can only be visible over very long distances. In this talk, I will discuss how analyzing the neutrino data from SN1987A in the light of active-sterile oscillations can present a mild preference for such oscillations. Notably, the same data is able to exclude some of the tiniest mass differences for neutrinos constrained so far. I will further discuss the prospects of using the ever-present diffuse supernova neutrino background as a laboratory to test the possible, albeit tiny, violation of lepton number.