On the relic abundance of light photinos

Abstract

We solve the coupled Boltzmann equation for the system of light photinos interacting with pions and $R^0$'s (the gluon-gluino bound state) to determine the relic abundance of light photinos in the light gaugino scenario. Cosmology bounds the ratio r of the R^0 mass to the photino mass to be less than about 1.8. We also use a model Lagrangian embodying crossing symmetry between the $R^0\leftrightarrow \text{photino}\pi \pi$ and $R^0\pi \leftrightarrow \text{photino}\pi$ reactions to identify cosmologically favored regions of $R^0$ lifetime as a function of $R^0$ and photino masses.

Comments: 29 page LaTeX file with 6 postscript figures included with epsf