A Dark Matter Solution from the Supersymmetric Axion Model.

Abstract

We study the effect of the late decaying saxino and find out that there is a possible dark matter solution from a class of supersymmetric extensions of the invisible axion model. In this class of models, the saxino acts as the late decaying particle which reconciles the cold dark matter model with high values of the Hubble constant ${H}_{0}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}70--80\mathrm{km}\mathrm{}{\mathrm{sec}}^{\ensuremath{-}1}{\mathrm{Mpc}}^{\ensuremath{-}1}$, which would be inconsistent with the standard mixed dark matter model. This class of models provides a plausible framework for the alternative cold dark matter plus late decaying particle model, with the interesting possibility that both cold dark matter and the extra radiation consist of an axion.