Neutrino Signatures in Primordial Non-Gaussianities
  We study the cosmological collider phenomenology of neutrinos in an effective
field theory. The mass spectrum of neutrinos and their characteristic
oscillatory signatures in the squeezed limit bispectrum are computed. Both
dS-covariant and slow-roll corrections are considered, so is the scenario of
electroweak symmetry breaking during inflation. Interestingly, we show that the
slow-roll background of the inflaton provides a chemical potential for the
neutrino production. The chemical potential greatly amplifies the oscillatory
signal and makes the signal observably large for heavy neutrinos without the
need of fine tuning.
