新山　雅之
   所属   京都産業大学  理学部 物理科学科
   職種   教授
発行・発表の年月 2022/10
形態種別 その他
標題 Determination of $|V_{ub}|$ from untagged $B^0\toπ^- \ell^+ ν_{\ell}$ decays using 2019-2021 Belle II data
執筆形態 その他
著者・共著者 Belle II Collaboration,K. Adamczyk,L. Aggarwal,P. Ahlburg,H. Ahmed,J. K. Ahn,H. Aihara,N. Akopov,A. Aloisio,F. Ameli,L. Andricek,N. Anh Ky,D. M. Asner,H. Atmacan,V. Aulchenko,T. Aushev,V. Aushev,T. Aziz,V. Babu,S. Bacher,H. Bae,S. Baehr,S. Bahinipati,A. M. Bakich,P. Bambade,Sw. Banerjee,S. Bansal,M. Barrett,G. Batignani,J. Baudot,M. Bauer,A. Baur,A. Beaubien,A. Beaulieu,J. Becker,P. K. Behera,J. V. Bennett,E. Bernieri,F. U. Bernlochner,V. Bertacchi,M. Bertemes,E. Bertholet,M. Bessner,S. Bettarin
概要 We present an analysis of the charmless semileptonic decay $B^0\to\pi^-
\ell^+ \nu_{\ell}$, where $\ell = e, \mu$, from 198.0 million pairs of
$B\bar{B}$ mesons recorded by the Belle II detector at the SuperKEKB
electron-positron collider. The decay is reconstructed without identifying the
partner $B$ meson. The partial branching fractions are measured independently
for $B^0\to\pi^- e^+ \nu_{e}$ and $B^0\to\pi^- \mu^+ \nu_{\mu}$ as functions of
$q^{2}$ (momentum transfer squared), using 3896 $B^0\to\pi^- e^+ \nu_{e}$ and
5466 $B^0\to\pi^- \mu^+ \nu_{\mu}$ decays. The total branching fraction is
found to be $(1.426 \pm 0.056 \pm 0.125) \times 10^{-4}$ for $B^0\to\pi^-
\ell^+ \nu_{\ell}$ decays, where the uncertainties are statistical and
systematic, respectively. By fitting the measured partial branching fractions
as functions of $q^{2}$, together with constraints on the nonperturbative
hadronic contribution from lattice QCD calculations, the magnitude of the
Cabibbo-Kobayashi-Maskawa matrix element $V_{ub}$, $(3.55 \pm 0.12 \pm 0.13 \pm
0.17) \times 10^{-3}$, is extracted. Here, the first uncertainty is
statistical, the second is systematic and the third is theoretical.
PermalinkURL http://arxiv.org/abs/2210.04224v2
researchmap用URL http://arxiv.org/pdf/2210.04224v2