Determining the Neutrino Lifetime From Cosmology

  • June 2, 2022, 2:30 pm US/Central
  • Abhish Dev, FNAL

Neutrinos are the most mysterious particles in the standard model. Many of their fundamental properties such as their masses, lifetimes, and nature (Dirac or Majorana) are yet to be pinned down by experiments. Currently, the strongest bound on neutrino masses comes from cosmology. This bound is obtained by scrutinizing the gravitational effect of the cosmic neutrinos on the evolution of structure in our universe. However, this bound assumes that the neutrinos from the Big Bang have survived until the present day. In this talk, I will consider the scenario of  unstable neutrino scenario in light of current and near-future cosmological experiments. We show that the current cosmological bound on the neutrino masses can be relaxed significantly in an unstable neutrino scenario. We further show that near-future experiments offer the possibility of independently measuring both the masses of the neutrinos and their lifetimes.