Cosmological Moduli Problem and Thermal Inflation Models

TL;DR

This paper investigates whether thermal inflation can resolve the cosmological moduli problem across a wide range of moduli masses predicted by superstring theories, considering various inflation scenarios and constraints.

Contribution

It provides a comprehensive analysis showing that thermal inflation can solve the moduli problem for masses from 10 eV to 10^4 GeV in different SUSY breaking models.

Findings

Thermal inflation can address the moduli problem across the entire mass range.

The moduli mass region of 10 eV to 10^4 GeV remains viable after cosmological constraints.

The study includes models with low reheating temperatures after primordial inflation.

Abstract

In superstring theories, there exist various dilaton and modulus fields which masses are expected to be of the order of the gravitino mass $m_{3/2}$. These fields lead to serious cosmological difficulties, so called ``cosmological moduli problem'', because a large number of moduli particles are produced as the coherent oscillations after the primordial inflation. We make a comprehensive study whether the thermal inflation can solve the cosmological moduli problem in the whole modulus mass region $m_\phi \sim 10 eV - 10^4 GeV$ predicted by both hidden sector supersymmetry (SUSY) breaking and gauge-mediated SUSY breaking models. In particular, we take into account the primordial inflation model whose reheating temperature is so low that its reheating process finishes after the thermal inflation ends. We find that the above mass region $m_\phi (\simeq m_{3/2}) \sim 10 eV - 10^4 GeV$ survives from various cosmological constraints in the presence of the thermal inflation.