New leading contributions to non-gaussianity in single field inflation

Abstract

We compute the bispectrum of primordial density perturbations in CMB to second order in the slow-roll parameters of single field inflation. We correct previous results and found that next-to-leading order corrections can be of the same order as the leading order result in a large class of models, including hilltop inflation.

Comments: 60 pages. v1: 4 appendices. v2: published version. 5 appendices