Implications of time-dependent inflaton decay on reheating and dark matter production

TL;DR

This paper investigates how a time-dependent inflaton decay rate during reheating affects radiation and dark matter production, revealing significant modifications to the dynamics and identifying parameter regions consistent with observed dark matter abundance.

Contribution

It introduces a model with a time-dependent inflaton decay rate influenced by inflaton-Higgs interactions, extending the standard reheating scenario.

Findings

Time dependence of decay rate alters reheating dynamics.

Modified dark matter production compared to constant decay rate.

Identified parameter space matching observed dark matter abundance.

Abstract

We discuss the production of radiation and dark matter assuming a time-dependent inflaton decay rate during the reheating period. It is shown that the time dependence of the inflaton decay rate can substantially modify the reheating dynamics. As an illustration, a leading interaction between the inflaton $\phi$ and the Higgs doublet ${\boldsymbol h}$ of the form $\phi |{\boldsymbol h}|^2$ was adopted. In the presence of such interaction, the Higgs doublet acquires a $\phi$-dependent mass which generates vacuum-expectation-value due to inflaton oscillations and breaks the Standard Model gauge symmetry. This leads to a time-dependent inflaton decay rate during the reheating period, and consequently, the production of radiation and dark matter during this period is modified. Regions of the parameter space that describe the observed value of the dark matter abundance were found and compared with the standard case when inflaton the decay rate is constant.