B-meson dileptonic decays enhanced by supersymmetry with large $\tan \beta$

Abstract

We examined the rare decays $B\to X_s{\ell }^{+}{\ell }^{-}$ and $B_s\to {\ell }^{+}{\ell }^{-}\gamma$ in the minimal supersymmetric model with large $\tan \beta$. Taking into account the gluino-loop and neutralino-loop effects, we found that for a large $\tan \beta$ the neutral Higgs exchanging diagrams could enhance $Br(B\to X_s{\tau }^{+}{\tau }^{-})$ by a factor of 5 and $Br(B_s\to {\tau }^{+}{\tau }^{-}\gamma )$ by a couple of orders in some part of supersymmetric parameter space allowed by current experiments such as $b\to s\gamma ,B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$ and $B_s\to {\ell }^{+}{\ell }^{-}$. 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.

Comments: 17 pages,9 figures, a detail contribution and reference added