Constraints on inflation with an extended neutrino sector

Abstract

Constraints on inflationary models typically assume only the standard models of cosmology and particle physics. By extending the neutrino sector to include a new interaction with a light scalar mediator (${m}_{\ensuremath{\phi}}\ensuremath{\sim}\mathrm{MeV}$), it is possible to relax these constraints, in particular via opening up regions of the parameter space of the spectral index ${n}_{s}$. These new interactions can be probed at IceCube via interactions of astrophysical neutrinos with the cosmic neutrino background for nearly all of the relevant parameter space.