Production of Massive Particles in The Post-inflationary Universe

Rouzbeh Allahverdi, TRIUMF

Stable or long-lived particles with a mass at or above the electroweak scale have important cosmological implications. I will briefly review production mechanisms of massive particles in the early Universe. In particular, it will be shown that they can be copiously produced from various perturbative processes during reheating, and subsequent thermalization, of the Universe after inflation. I will argue that non-thermal LSP (Lightest Supersymmetric Particle) or superheavy dark matter usually leads to tight constraints on inflationary model parameters. Also, in large extra dimension models, non-thermal production of Kaluza-Klein modes of the graviton typically results in stronger bounds on the quantum gravity scale. As a closing remark, I will touch upon the possibility of testing different scenarios of non-thermal dark matter through CMB.