Applying the microcanonical definition of entropy to a weakly interacting and self–gravitating neutralino gas , we evaluate the change in the local entropy per particle of this gas between the freeze out era and present day virialized halo structures .
An “ entropy consistency ” criterion emerges by comparing theoretical and empirical estimates of this entropy .
We apply this criterion to the cases when neutralinos are mostly B-inos and mostly Higgsinos , in conjunction with the usual “ abundance ” criterion requiring that present neutralino relic density complies with 0.2 < \Omega _ { { \tilde { \chi } ^ { 1 } _ { 0 } } } < 0.4 for h \simeq 0.65 .
The joint application of both criteria reveals that a much better fitting occurs for the B-ino than for the Higgsino channels , so that the former seems to be a favored channel along the mass range of 155 \hbox { GeV } < m _ { { \tilde { \chi } ^ { 1 } _ { 0 } } } < 230 \hbox { GeV } .
These results are consistent with neutralino annihilation patterns that emerge from recent theoretical analysis on cosmic ray positron excess data reported by the HEAT collaboration .
The suggested methodology can be applied to test other annihilation channels of the neutralino , as well as other particle candidates of thermal WIMP gas relics .