On the thermal footsteps of Neutralino relic gases

Abstract

Current literature suggests that neutralinos are the dominant cold dark matter particle species. Assuming the microcanonical definition of entropy, we examine the local entropy per particle produced between the ``freeze out'' era to the present. An ``entropy consistency'' criterion emerges by comparing this entropy with the entropy per particle of actual galactic structures given in terms of dynamical halo variables. We apply this criterion to the cases when neutralinos are mosly b-inos and mostly higgsinos, in conjunction with the usual ``abundance'' criterion requiring that present neutralino relic density complies with $0.1 < \Omega_{\chic{\tilde\chi^0_1}} < 0.3$ for $h\simeq 0.65$. The joint application of both criteria reveals that a better fitting occurs for the b-ino channels, hence the latter seem to be favoured over the higgsino channels. The suggested methodology can be applied to test other annihilation channels of the neutralino, as well as other particle candidates of thermal gases relics.