Particle production in the oscillating inflation model

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