17-24 July 2013
KTH and Stockholm University Campus
Europe/Stockholm timezone

New physics searches at Belle

19 Jul 2013, 09:45
D1 (KTH Campus)


KTH Campus

Talk presentation Flavour Physics and Fundamental Symmetries Flavour Physics and fundamental symmetries


Jan Hasenbusch (Univ. of Bonn)


We report the first branching fraction measurement of the inclusive Cabibbo favoured semileptonic decay $B\to X_c \tau\nu$ by the Belle experiment. The branching fraction of this kinematically suppressed mode is highly sensitive to new physics beyond the Standard Model, such as a charged Higgs, which couples strongly to the massive $\tau$ lepton and interfere with the Standard Model process. This measurement will shed light on the contributions from all tauonic $B$ decay modes, including high mass and non-resonant contributions, $B \to D^{**}/D^{(*)}n\pi \tau \nu$ which may be the cause for observed excesses above the SM in the exclusive channels. The full Belle dataset is used, containing 772 million $B\bar{B}$ meson pairs recorded near the $\Upsilon(4S)$ resonance at the KEKB asymmetric-energy $e^+e^-$ collider. The $B$ meson events are tagged by fully reconstructing one $B$ in a hadronic mode. The charm meson on the signal side is identified by the presence of a wrong-sign lepton, and the $\tau$ is reconstructed in several leptonic and hadronic modes. Multivariate selection techniques are used to optimise the signal selection.

Primary author

Prof. Youngjoon Kwon (Yonsei University)

Presentation Materials