B-meson dileptonic decays enhanced by supersymmetry with large tan β

Abstract

We examined the rare decays B→ X s ℓ +ℓ − and B s →ℓ +ℓ − γ in the minimal supersymmetric model with large tan β. Taking into account the effects of the gluino-loop and neutralino-loop with neutral Higgs exchange, we found that for a large tan β the neutral Higgs exchanging diagrams could enhance Br( B→ X s τ + τ −) by a factor of 5 and Br( B s → τ + τ − γ) by a couple of orders in some part of supersymmetric parameter space allowed by current experiments such as b→sγ,B→K (∗)ℓ +ℓ − and B s →ℓ +ℓ −. The forward–backward asymmetry and the distributions of differential branching ratios are also found to differ significantly from the standard model results. Such enhanced branching ratios reach the level of 10 −5 and thus might be observable in the new generation of B experiments.