Determination of |Vcb| from BDν decays using 2019--2021 Belle II data

Sumitted to PubDB: 2022-10-19

Category: Conference papers and plots, Visibility: Public

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Authors Philipp Horak, Christoph Schwanda
Date Oct. 19, 2022
Belle II Number BELLE2-CONF-PH-2022-010
Abstract We present a determination of the magnitude of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vcb using the decay BDν based on e+eΥ(4S)~data recorded by the Belle II detector and corresponding to \lumi of integrated luminosity. The semileptonic decays \ensuremath{\Bz \to D^{-}(\to K^+ \pi^- \pi^-) \ell^{+} \nu_\ell}\xspace and \ensuremath{\Bp \to \bar D^{0}(\to K^+\pi^-) \ell^{+} \nu_\ell}\xspace are reconstructed, where is either electron or a muon. The second B~meson in the Υ(4S)~event is not explicitly reconstructed. Using the diamond-frame method, we determine the B~meson four-momentum and thus the hadronic recoil. We extract the partial decay rates as functions of w and perform a fit to the decay form-factor and the magnitude of the CKM matrix element |Vcb| using the BGL parameterization of the form factor and lattice QCD input from the FNAL/MILC and HPQCD collaborations. We obtain \resVcb, where ηEW is an electroweak correction, and the error accounts for theoretical and experimental sources of uncertainty.

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