Rate difference between b $\to$ s mu^+ mu^- and b $\to$ s e^+e^- in SUSY with large tan$\beta$

Abstract

We study the inclusive semileptonic rare decay $b\to s{l}^{+}{l}^{-}$ in minimal supergravity model (mSUGRA). If tan$\beta$ is large, down-type quark mass matrices and their Yukawa couplings cannot be diagonalized at the same basis. This induces the flavor violating neutral Higgs boson couplings. These couplings contribute significantly to decay $b\to sm{u}^{+}m{u}^{-}$ and $b\to sta{u}^{+}ta{u}^{-}$, but negligible to $b\to s{e}^{+}{e}^{-}$ decay because of its negligible $m_e$ mass. The ratio $R\equiv B(b\to sm{u}^{+}m{u}^{-})/B(b\to s{e}^{+}{e}^{-})$ can be very different from its corresponding value in the Standard Model. We find that part of parameter space can accommodate a large R value, and that maximum R value can be larger than 2. We also present our results in $b\to sta{u}^{+}ta{u}^{-}$ decay channel. Although it can be not detected now, it is potentially a new channel for the future observation of new physics.

Comments: 9 pages and 4 figures