GUT baryogenesis after preheating: numerical study of the production and decay of X-bosons

We perform a fully non-linear calculation of the production of supermassive Grand Unified Theory (GUT) X bosons during preheating, taking into account the fact that they are unstable with a decay width ΓX. We show that parametric resonance does not develop if ΓX is larger than about 10−2mX. We compute the nonthermal number density of superheavy bosons produced in the preheating phase and demonstrate that the observed baryon asymmetry may be explained by GUT baryogenesis after preheating if ΓX is smaller than about 10−3mX.