Non-Gaussianities in extended D-term inflation

TL;DR

This paper investigates extended supersymmetric D-term inflation models, demonstrating that multiple fields can produce significant primordial non-Gaussianities while maintaining a scale-invariant power spectrum, with implications for CMB observations.

Contribution

It introduces a comprehensive analysis of multi-field D-term inflation models, highlighting their potential to generate observable non-Gaussianities and providing explicit calculations of bi- and trispectra.

Findings

Large parameter space for non-Gaussianity in multi-field models

Explicit bi- and trispectrum calculations

Both spectra needed to constrain models effectively

Abstract

We explore extensions of hybrid inflationary models in the context of supersymmetric D-term inflation. We point out that a large variety of inflationary scenarios can be encountered when the field content is extended. It is not only possible to get curvaton type models but also scenarios in which different fields, with nontrivial statistical properties, contribute to the primordial curvature fluctuations. We explore more particularly the parameter space of these multiple field inflationary models. It is shown that there exists a large domain in which significant primordial non-Gaussianities can be produced while preserving a scale free power spectrum for the metric fluctuations. In particular we explicitly compute the expected bi- and trispectrum for such models and compared the results to the current and expected observational constraints. It is shown that it is necessary to use both the bi- and tri-spectra of CMB anisotropies to efficiently reduce their parameter space.