Positron Fraction in the CMSSM

A fit to the present data on the cosmic ray positron fraction can be considerably improved,if in addition to the positron production by nuclear interactions in the universe the possible contribution from supersymmetric dark matter annihilation is taken into account. We scan over the complete SUSY parameter space of the Constrained Minimal Supersymmetric Model (CMSSM) and find that in the acceptable regions the neutralino annihilation into b-bbar quark pairs is the dominant channel with hard positrons emerging from the semileptonic decays of the B-mesons.