Hamburg 2016 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 54: Seltene Zerfälle und BSM im Flavourbereich
T 54.5: Vortrag
Dienstag, 1. März 2016, 17:50–18:05, VMP8 SR 05
Measurement of the inclusive B→ Xsγ branching fraction and spectral moments. — •Luis Pesantez and Jochen Dingfelder for the Belle collaboration — Physikalisches Institut, Universitaet Bonn
The Belle detector at the KEKB e+ e− collider recorded 770 × 106 B B pairs produced at the Υ(4S) resonance. In the analysis presented here, the rare radiative decay of B → Xs γ was investigated. The study of this decay is interesting as it probes QCD properties of B-mesons and the rate can be considerably enhanced due to new physics effects: the decay, forbidden at tree-level in the Standard Model of particle physics, is loop-mediated and new charged particles, such as charged Higgs bosons, would alter the rate. The current experimental world average of the branching fraction and the SM prediction are in good agreement. The measured branching fractions also severely constrain a scenario with a charged Higgs boson in the Two-Higgs-Doublet Model of type II, which is a candidate of the Higgs sector of the supersymmetric extension of the Standard Model. In this presentation the current status of the legacy Belle analysis of the B → Xs γ branching fraction is shown using an inclusive approach. In particular, the status of the measurement of the differential shape, spectral moments and the extraction of QCD parameters will be summarized.