Speaker
Description
We present the results of measurement of electroweak penguin B decays. We show the full angular analysis of $B \to K^* \ell^+ \ell^-$ to extract form factor insensitive variables such as $P'_5$. The branching fraction of inclusive $b \to s \ell^+ \ell^-$ is measured with a sum-of-exclusive-modes approach. We also report searches for leptonic $B$ decays including the lepton-flavor-violating mode: $B \to e^+e^-$, $\mu^+\mu^-$, $\tau^+\tau^-$, $e^\pm \mu^\mp$. All the analyses are based on the full data set of Belle containing 772 million $B\overline{B}$ pairs.
A related decay $B_s \to \tau^+\tau^-$ can also be studied by a hadronic $B_s$ tagging tool that is being developed for the data sample of 121${\rm fb}^{-1}$ collected at the $\Upsilon(10860)$ resonance at Belle. The method is based on a hierarchical approach in which the $B_s $ mesons and their daughters are reconstructed in several stages, harnessing more than 100 neural network variables.
