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arXiv · 2104.13354

Measurement of the branching fractions of the $B^+ \to \eta \ell^+ \nu_{\ell} $ and $B^+ \to \eta^{\prime} \ell^+ \nu_{\ell} $ decays with signal-side only reconstruction in the full $q^2$ range

Belle Collaboration·U. Gebauer·C. Beleño·A. Frey·I. Adachi·K. Adamczyk·H. Aihara·S. Al Said·D. M. Asner·H. Atmacan·T. Aushev·R. Ayad·V. Babu·S. Bahinipati·P. Behera·K. Belous·J. Bennett·M. Bessner·V. Bhardwaj·B. Bhuyan·T. Bilka·J. Biswal·A. Bobrov·G. Bonvicini·A. Bozek·M. Bračko·T. E. Browder·M. Campajola·L. Cao·D. Červenkov·M. -C. Chang·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·H. E. Cho·K. Cho·S. -J. Cho·S. -K. Choi·Y. Choi·S. Choudhury·D. Cinabro·S. Cunliffe·S. Das·N. Dash·G. De Nardo·F. Di Capua·J. Dingfelder·Z. Doležal·T. V. Dong·S. Eidelman·D. Epifanov·T. Ferber·D. Ferlewicz·B. G. Fulsom·R. Garg·V. Gaur·N. Gabyshev·A. Garmash·A. Giri·P. Goldenzweig·B. Golob·K. Gudkova·C. Hadjivasiliou·S. Halder·T. Hara·O. Hartbrich·K. Hayasaka·H. Hayashii·M. T. Hedges·W. -S. Hou·C. -L. Hsu·T. Iijima·K. Inami·A. Ishikawa·R. Itoh·M. Iwasaki·Y. Iwasaki·W. W. Jacobs·S. Jia·Y. Jin·C. W. Joo·K. K. Joo·J. Kahn·A. B. Kaliyar·K. H. Kang·G. Karyan·T. Kawasaki·H. Kichimi·C. Kiesling·C. H. Kim·D. Y. Kim·S. H. Kim·Y. -K. Kim·K. Kinoshita·P. Kodyš·T. Konno·A. Korobov·S. Korpar·E. Kovalenko
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Abstract

The branching fractions of the decays $B^{+} \to \eta \ell^{+} \nu_{\ell}$ and $B^{+} \to \eta^{\prime} \ell^{+} \nu_{\ell}$ are measured, where $\ell$ is either an electron or a muon, using a data sample of $711\,{\rm fb}^{-1}$ containing $772 \times 10^6 B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. To reduce the dependence of the result on the form factor model, the measurement is performed over the entire $q^2$ range. The resulting branching fractions are ${\cal B}(B^{+} \rightarrow \eta \ell^{+} \nu_{\ell}) = (2.83 \pm 0.55_{\rm (stat.)} \pm 0.34_{\rm (syst.)}) \times 10^{-5}$ and ${\cal B}(B^{+} \rightarrow \eta' \ell^{+} \nu_{\ell}) = (2.79 \pm 1.29_{\rm (stat.)} \pm 0.30_{\rm (syst.)}) \times 10^{-5}$.

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Belle Collaboration, U. Gebauer, C. Beleño, A. Frey, I. Adachi, K. Adamczyk, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, M. Campajola, L. Cao, D. Červenkov, M. -C. Chang, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. -J. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Das, N. Dash, G. De Nardo, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, S. Eidelman, D. Epifanov, T. Ferber, D. Ferlewicz, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, A. Giri, P. Goldenzweig, B. Golob, K. Gudkova, C. Hadjivasiliou, S. Halder, T. Hara, O. Hartbrich, K. Hayasaka, H. Hayashii, M. T. Hedges, W. -S. Hou, C. -L. Hsu, T. Iijima, K. Inami, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, S. Jia, Y. Jin, C. W. Joo, K. K. Joo, J. Kahn, A. B. Kaliyar, K. H. Kang, G. Karyan, T. Kawasaki, H. Kichimi, C. Kiesling, C. H. Kim, D. Y. Kim, S. H. Kim, Y. -K. Kim, K. Kinoshita, P. Kodyš, T. Konno, A. Korobov, S. Korpar, E. Kovalenko. 2021-04-27. Measurement of the branching fractions of the $B^+ \to \eta \ell^+ \nu_{\ell} $ and $B^+ \to \eta^{\prime} \ell^+ \nu_{\ell} $ decays with signal-side only reconstruction in the full $q^2$ range. https://doi.org/10.1103/physrevd.106.032013

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