Testing supersymmetric Higgs inflation with non-Gaussianity

TL;DR

This paper explores the signatures of multi-field supersymmetric Higgs inflation models, focusing on non-Gaussianities and their potential to reveal supergravity aspects through cosmological observations.

Contribution

It provides a detailed analysis of non-Gaussianities in a two-field Higgs-lepton inflation model within supergravity, connecting particle phenomenology with cosmological data.

Findings

Constraints on noncanonical Kähler potential terms from Planck data

Primordial non-Gaussianities can probe supergravity features

Inflationary observables depend on initial conditions and Kähler coefficients

Abstract

We investigate multi-field signatures of the nonminimally coupled supersymmetric Higgs inflation-type cosmological scenario, focusing on the two-field Higgs-lepton inflation model as a concrete example. This type of inflationary model is realized in a theory beyond the Standard Model embedded in supergravity with a noncanonical K\"{a}hler potential. We employ the backward $\delta N$ formalism to compute cosmological observables, including the scalar and tensor power spectra, the spectral indices, the tensor-to-scalar ratio and the local-type nonlinearity parameter. The trajectory of the inflaton is controlled by the initial conditions of the inflaton as well as by the coefficients in the K\"{a}hler potential. We analyze the bispectrum of the primordial fluctuations when the inflaton trajectory deviates from a straight line, and obtain constraints on the noncanonical terms of the K\"{a}hler potential using the Planck satellite data. Our analysis represents a concrete particle phenomenology-based case study of inflation in which primordial non-Gaussianities can reveal aspects of supergravity.