Particle production in the oscillating inflation model

Abstract

We investigate the particle production of a scalar field $χ$ coupled to an inflaton field $ϕ$ ($g^2ϕ^2χ^2/2$) in the {\it oscillating inflation} model, which was recently proposed by Damour and Mukhanov. Although the fluctuation of the $ϕ$ field can be effectively enhanced during a stage of the oscillating inflation, the maximum fluctuation is suppressed as the critical value $ϕ_c$ which indicates the scale of the core part of the inflaton potential decreases, in taking into account the back reaction effect of created particles. As for the $χ$ particle production, we find that larger values of the coupling constant $g$ are required to lead to an efficient parametric resonance with the decrease of $ϕ_c$, because an effective mass of inflaton around the minimum of its potential becomes larger. However, it is possible to generate the superheavy $χ$ particle whose mass is greater than $10^{14}$ GeV, which would result in an important consequence for the GUT baryogenesis.