Non-Oscillatory No-Scale Inflation

TL;DR

This paper introduces a non-oscillatory no-scale supergravity inflation model where the universe transitions directly from inflation to a kinetic energy dominated phase, with instant preheating and consistent cosmological predictions.

Contribution

It presents a novel non-oscillatory inflation model with instant preheating and a tracking phase, aligning with observational data and addressing reheating without inflaton oscillations.

Findings

Predictions match Planck 2018 CMB data.

Gravitational wave density below BBN bounds.

Dark matter density consistent with observations.

Abstract

We propose a non-oscillatory no-scale supergravity model of inflation (NO-NO inflation) in which the inflaton does not oscillate at the end of the inflationary era. Instead, the Universe is then dominated by the inflaton kinetic energy density (kination). During the transition from inflation to kination, the Universe preheats instantly through a coupling to Higgs-like fields. These rapidly annihilate and scatter into ultra-relativistic matter particles, which subsequently dominate the energy density, and reheating occurs at a temperature far above that of Big Bang Nucleosynthesis. After the electroweak transition, the inflaton enters a tracking phase as in some models of quintessential inflation. The model predictions for cosmic microwave background observables are consistent with Planck 2018 data, and the density of gravitational waves is below the upper bound from Big Bang Nucleosynthesis. We also find that the density of supersymmetric cold dark matter produced by gravitino decay is consistent with Planck 2018 data over the expected range of supersymmetric particle masses.