Sneutrino Hybrid Inflation in Supergravity

Abstract

We propose a hybrid inflation scenario in which the singlet sneutrino, the superpartner of the right-handed neutrino, plays the role of the inflaton. We study a minimal model of sneutrino hybrid inflation in supergravity, where we find a spectral index $n_s \approx 1 + 2 \gamma$ with $|\gamma| \lesssim 0.02$, and predict a running spectral index $|d n_s/d\ln k| \ll |\gamma|$ and a tensor-to-scalar ratio $r \ll \gamma^2$ for field values well below the Planck scale. In our scenario, the baryon asymmetry of our universe can be explained via non-thermal leptogenesis and a low reheat temperature $T_{RH} \approx 10^{6}$ GeV can be realized.