Sensitivity of Supersymmetric Dark Matter to the b Quark Mass

An analysis of the sensitivity of supersymmetric dark matter to variations in the b quark mass is given. Specifically we study the effects on the neutralino relic abundance from supersymmetric loop corrections to the mass of the b quark. It is known that these loop corrections can become significant for large $\tan\beta$. The analysis is carried out in the framework of mSUGRA and we focus on the region where the relic density constraints are satisfied by resonant annihilation through the s-channel Higgs poles. We extend the analysis to include CP phases taking into account the mixing of the CP-even and CP-odd Higgs boson states which play an important role in determining the relic density. Implications of the analysis for the neutralino relic density consistent with the recent WMAP relic density constraints are discussed.