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

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.