LATE-TIME ENTROPY PRODUCTION AND RELIC ABUNDANCES OF NEUTRALINOS

Many models possess unwanted relies, which should be diluted by entrop y production just before the big-bang nucleosynthesis. A field respons ible for the entropy production may produce stable weakly interacting massive particles, if kinematically accessible. We compute their relic abundances by integrating out coupled equations numerically. Applying our results to supersymmetric standard models, we argue that the neut ralino lightest superparticles will overdose the universe in most of t he parameter space if the reheat temperature is of the order of 10 MeV . (C) 1998 Elsevier Science B.V. All rights reserved.