Tilted Hybrid Inflation

Abstract

We propose a new version of the hybrid inflation scenario that produces a significantly tilted n>1 spectrum of curvature perturbations. This may happen in supersymmetric models where the inflaton field acquires a mass proportional to the Hubble constant, and in the models where this field non-minimally couples to gravity. A large tilt of the spectrum in this scenario is often accompanied by a considerable contribution of tensor perturbations to the temperature anisotropies. We also show that under certain conditions the spectrum of density perturbations in this scenario may have a minimum on an intermediate length scale.