Particle production in the oscillating inflation model

Abstract

We investigate the particle production of a scalar field $\ensuremath{\chi}$ coupled to an inflaton field $\ensuremath{\varphi}$ ${(g}^{2}{\ensuremath{\varphi}}^{2}{\ensuremath{\chi}}^{2}/2)$ in the oscillating inflation model, which was recently proposed by Damour and Mukhanov. Although the fluctuation of the $\ensuremath{\varphi}$ field can be effectively enhanced during a stage of the oscillating inflation, the maximum fluctuation is suppressed as the critical value ${\ensuremath{\varphi}}_{c}$ 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 $\ensuremath{\chi}$ 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 ${\ensuremath{\varphi}}_{c},$ because an effective mass of inflaton around the minimum of its potential becomes larger. However, it is possible to generate the superheavy $\ensuremath{\chi}$ particle whose mass is greater than ${10}^{14}$ GeV, which would result in an important consequence for the GUT baryogenesis.