Gravitino production during preheating

Abstract

We study the production of gravitinos during the preheating era after inflation by means of the non-perturbative Bogolyubov technique. Considering only the helicity $\pm 3/2$ states, the problem is reduced to the simpler Dirac fermions case. We calculate the production in a particular supergravity model in an expanding universe and obtain the spectrum and number density. Finally we compare the results with the nucleosynthesis bounds and extract some consequences.

Comments: 10 pages, LaTeX, 2 figures. Talk given in the International Workshop on Particles in Astrophysics and Cosmology, Valencia (Spain), May 3-8, 1999