Gravitational inflaton decay and the hierarchy problem

Understand

We study implications of the large-N species solution to the hierarchy problem, proposed by G.

• Dvali, for reheating of the universe after inflation.
• Dvali's proposal contains additional N~10^{32} Z_2-conserved quantum fields beyond the Standard Model particles with mass ~1 TeV, which weaken gravity by a factor of 1/N, and thus explain the hierarchy between the Plank scale and the electroweak scale.
• We show that, in this scenario, the decay rates of inflaton fields through gravitational decay channels are enhanced by a factor of N, and thus they decay into N species of the quantum fields very efficiently, in the limit that quantum gravity effects are unimportant for the gravitational decay rate.