000002712 001__ 2712
000002712 005__ 20211007091146.0
000002712 037__ $$aBELLE2-CONF-PH-2021-011
000002712 041__ $$aeng
000002712 100__ $$aPhilipp Horak ; Christoph Schwanda
000002712 245__ $$aMeasurement of the $B^-\to D^0 \ell^- \bar\nu_\ell$ Branching Fraction in 62.8~fb$^{-1}$ of Belle II data
000002712 260__ $$a$$c2021-10-07
000002712 300__ $$a17
000002712 520__ $$aWe report a measurement of the branching fraction of the semileptonic decay \bdlnu (and its charge conjugate) using \mbox{$62.8~\text{fb}^{-1}$} of $\Upsilon(4S)\to B\bar B$~data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e^+ e^-$ collider. The neutral charm meson is searched for in the decay mode $D^0\to K^-\pi^+$ and combined with a properly charged identified lepton (electron or muon) to reconstruct this decay. No reconstruction of the second $B$~meson in the $\Upsilon(4S)$~event is performed. We obtain ${\cal B}(B^-\to D^0 \ell^-\bar\nu_\ell) = (2.293\pm 0.053_\mathrm{stat}\pm 0.084_\mathrm{syst})\%$, in agreement with the world average of this decay. We also determine the ratio of the electron to muon branching fractions to be $R(e/\mu) = 1.044 \pm 0.046_\mathrm{stat} \pm 0.034_\mathrm{syst}$ and observe no deviation from lepton universality.
000002712 8560_ $$fchristoph.schwanda@oeaw.ac.at
000002712 8564_ $$uhttps://docs.belle2.org/record/2712/files/BELLE2-CONF-PH-2021-011.pdf