New inflation in supergravity after Planck and LHC

TL;DR

This paper examines a supergravity-based new inflation model, addressing its spectral index discrepancy with Planck data by introducing a small superpotential constant, linking inflation, supersymmetry breaking, and the landscape.

Contribution

It proposes a modification to the supergravity inflation model to reconcile spectral index predictions with observational data, considering the role of a small superpotential constant.

Findings

Heavy gravitino mass consistent with Higgs mass

Spectral index can be increased with a small superpotential constant

Potential link between inflation dynamics and supersymmetry breaking

Abstract

We revisit a single-field new inflation model based on a discrete R symmetry. Interestingly, the inflaton dynamics naturally leads to a heavy gravitino of mass m_3/2 = O(1-100) TeV, which is consistent with the standard-model like Higgs boson of mass mh = 126 GeV. However, the predicted spectral index n_s = 0.94 is in tension with the Planck result, n_s = 0.9603+-0.073. We show that the spectral index can be increased by allowing a small constant term in the superpotential during inflation. The required size of the constant is close to the largest allowed value for successful inflation, and it may be a result of a pressure toward larger values in the landscape. Alternatively, such constant term may arise in association with supersymmetry breaking required to cancel the negative cosmological constant from the inflaton sector.