Phenomenology of $B\rightarrow X_s \ell \ell$
Enrico Lunghi, T. Huber, M. Misiak, D. Wyler · Proceedings of International Europhysics Conference on High Energy Physics — PoS(HEP2005) · 2007
We present a brief review of the status and phenomenology of B X s decays.The B X s rate is known at the next-to-next-to-leading order in QCD and NLO in QED.QED corrections include only log-enhanced corrections of the type α em ln M 2 W m 2 b and α em ln m 2 b m 2 .The latter originate from a collinear singularity, they vanish when integrated over the whole phase space but survive the integration over the low dilepton invariant mass region 1 GeV 2 m 2 6 GeV 2 .For the low-m 2 integrated branching ratio in the muonic case, we find B X s µ µ 1 59 0 11 10 6 , where the error includes the parametric and perturbative un- certainties only.For B X s e e , in the current BaBar and Belle setups, the logarithm of the lepton mass gets replaced by angular cut parameters.In effect, the integrated branching ratio for the electrons is expected to be close to that for the muons.