Motoi Endo (DESY):

Gravitino Overproduction from Scalar Decay

Abstract:

We investigate the cosmological moduli problem by studying a modulus decay in detail and find that the branching ratio of the gravitino production is generically of O(0.01-1), which causes another cosmological disaster. Consequently, the cosmological moduli problem cannot be solved simply by making the modulus mass heavier than 100 TeV. The similar problem arises in an inflaton decay. We will touch on the inflaton case.