Production of massive stable particles in inflaton decay

Abstract

We point out that inflaton decays can be a copious source of stable or long--lived particles $χ$ with mass exceeding the reheat temperature $T_R$. Once higher order processes are included, this statement is true for any $χ$ particle with renormalizable (gauge or Yukawa) interactions. This contribution to the $χ$ density often exceeds the contribution from thermal $χ$ production, leading to significantly stronger constraints on model parameters than those resulting from thermal $χ$ production alone. For example, we all but exclude models containing stable charged particles with mass less than half the mass of the inflaton.