Late-time creation of gravitinos from the vacuum

David H. Lyth
2000 Physics Letters B  
Starting with the vacuum fluctuation, it is known that gravitinos will be created just after inflation, with number density ∼ 10^-2M^3 where M is the mass of the inflaton. Here, we argue that creation may be expected to continue, maintaining about the same number density, until a usually much later epoch. This epoch is either the 'intermediate epoch' when Hubble parameter falls below the gravitino mass, or the reheat epoch if that is earlier. We verify that such late-time creation indeed occurs
more » ... if only a single chiral superfield is relevant, using the description of the helicity 1/2 gravitino provided recently by Kallosh et. al. (hep-th/9907124) and Giudice et. al. (hep-ph/9907510). Arguments are presented in favor of late-time creation in the general case. For the usual inflation models, M is rather large and gravitinos from late-time creation are so abundant that a subsequent era of thermal inflation is needed to dilute them.
doi:10.1016/s0370-2693(00)00156-8 fatcat:roaokmyqlzbgtkoqt4qe5pn3pu