NUK - logo
E-viri
Celotno besedilo
Odprti dostop
  • First Measurement of $R(X_{\tau/\ell})$ as an Inclusive Test of the $b \to c \tau \nu$ Anomaly
    Adachi, I; Asner, D. M; Aushev, V; Bahinipati, S; Bansal, S; Beaubien, A; Bertacchi, V; Bianchi, F; Bilokin, S; Biswas, D; Budano, A; Campajola, M; Cao, L; Casarosa, G; Cerasoli, J; Chirapatpimol, K; Cho, K; Dattola, F; de Marino, G; Destefanis, M; Dubey, S; Dujany, G; Epifanov, D; Ferber, T; Ferlewicz, D; Fillinger, T; Fodor, A; Forti, F; Garcia-Hernandez, M; Garg, R; Gaur, V; Gaz, A; Ghosh, D; Ghumaryan, H; Greenwald, D; Gruberová, Z; Gu, T; Hara, T; de la Cruz, I. Heredia; Higuchi, T; Hohmann, M; Horak, P; Iwasaki, M; Jackson, P; Kawasaki, T; Keil, F; Kiesling, C; Kim, C. -H; Korobov, A; Kowalewski, R; Križan, P; Kulii, Y; Kumar, M; Kumara, K; Lacaprara, S; Lange, J. S; Levit, D; Liu, Q. Y; Luo, T; Ma, Y; Maggiora, M; Maity, S; Manfredi, R; Manthei, A. C; Mantovano, M; Marinas, C; Matsuda, T; Mehta, R; Merola, M; Mizuk, R; Mohanty, G. B; Moser, H. -G; Nakao, M; Naruki, M; Natkaniec, Z; Otani, F; Pestotnik, R; Podesta-Lerma, P. L. M; Podobnik, T; Prim, M. T; Rados, P; Rauls, N; Rout, N; Russo, G; Savinov, V; Shi, X. D; Shimasaki, T; Shiu, J. -G; Tamponi, U; Tittel, O; Uematsu, Y; Urquijo, P; Varvell, K. E; Veronesi, M; Wallner, S; Warburton, A; Wessel, C; Yoshihara, K; Zhang, Y; Zhukova, V. I

    11/2023
    Journal Article

    Phys. Rev. Lett. 132, 211804 (2024) We measure the tau-to-light-lepton ratio of inclusive $B$-meson branching fractions $R(X_{\tau/\ell}) \equiv \mathcal{B}(B\to X \tau \nu)/\mathcal{B}(B \to X \ell \nu)$, where $\ell$ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed $B$ meson and a charged lepton candidate from $189~\mathrm{fb}^{-1}$ of electron-positron collision data collected with the Belle II detector. We find $R(X_{\tau/\ell}) = 0.228 \pm 0.016~(\mathrm{stat}) \pm 0.036~(\mathrm{syst})$, in agreement with standard-model expectations. This is the first direct measurement of $R(X_{\tau/\ell})$.

Vnos na polico