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arXiv · 2107.13855

Measurement of Differential Branching Fractions of Inclusive ${B \to X_u \, \ell^+\, \nu_{\ell}}$ Decays

Belle Collaboration·L. Cao·W. Sutcliffe·R. Van Tonder·F. U. Bernlochner·I. Adachi·H. Aihara·D. M. Asner·T. Aushev·V. Babu·S. Bahinipati·P. Behera·K. Belous·J. Bennett·M. Bessner·T. Bilka·J. Biswal·A. Bobrov·M. Bračko·P. Branchini·T. E. Browder·A. Budano·M. Campajola·D. Červenkov·M. -C. Chang·P. Chang·B. G. Cheon·K. Chilikin·H. E. Cho·K. Cho·S. -J. Cho·Y. Choi·S. Choudhury·D. Cinabro·S. Cunliffe·T. Czank·N. Dash·G. De Pietro·R. Dhamija·F. Di Capua·J. Dingfelder·Z. Doležal·T. V. Dong·S. Dubey·D. Epifanov·T. Ferber·D. Ferlewicz·A. Frey·B. G. Fulsom·R. Garg·V. Gaur·N. Gabyshev·A. Garmash·A. Giri·P. Goldenzweig·T. Gu·K. Gudkova·S. Halder·T. Hara·O. Hartbrich·K. Hayasaka·M. Hernandez Villanueva·W. -S. Hou·C. -L. Hsu·K. Inami·A. Ishikawa·R. Itoh·M. Iwasaki·W. W. Jacobs·E. -J. Jang·S. Jia·Y. Jin·K. K. Joo·J. Kahn·K. H. Kang·H. Kichimi·C. Kiesling·C. H. Kim·D. Y. Kim·S. H. Kim·Y. -K. Kim·T. D. Kimmel·K. Kinoshita·P. Kodyš·T. Konno·A. Korobov·S. Korpar·E. Kovalenko·P. Križan·R. Kroeger·P. Krokovny·T. Kuhr·R. Kulasiri·M. Kumar·R. Kumar·K. Kumara·A. Kuzmin·Y. -J. Kwon·S. C. Lee·C. H. Li
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Abstract

The first measurements of differential branching fractions of inclusive semileptonic ${B \to X_u \, \ell^+\, \nu_{\ell}}$ decays are performed using the full Belle data set of 711 fb$^{-1}$ of integrated luminosity at the $\Upsilon(4S)$ resonance and for $\ell = e, \mu$. Differential branching fractions are reported as a function of the lepton momentum, the four-momentum-transfer squared, light-cone momenta, the hadronic mass, and the hadronic mass squared. They are obtained by subtracting the backgrounds from semileptonic ${B \to X_c \, \ell^+\, \nu_{\ell}}$ decays and other processes, and corrected for resolution and acceptance effects. The measured distributions are compared to predictions from inclusive and hybrid ${B \to X_u \, \ell^+\, \nu_{\ell}}$ calculations.

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Belle Collaboration, L. Cao, W. Sutcliffe, R. Van Tonder, F. U. Bernlochner, I. Adachi, H. Aihara, D. M. Asner, T. Aushev, V. Babu, S. Bahinipati, P. Behera, K. Belous, J. Bennett, M. Bessner, T. Bilka, J. Biswal, A. Bobrov, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M. -C. Chang, P. Chang, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. -J. Cho, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, T. Czank, N. Dash, G. De Pietro, R. Dhamija, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, S. Dubey, D. Epifanov, T. Ferber, D. Ferlewicz, A. Frey, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, A. Giri, P. Goldenzweig, T. Gu, K. Gudkova, S. Halder, T. Hara, O. Hartbrich, K. Hayasaka, M. Hernandez Villanueva, W. -S. Hou, C. -L. Hsu, K. Inami, A. Ishikawa, R. Itoh, M. Iwasaki, W. W. Jacobs, E. -J. Jang, S. Jia, Y. Jin, K. K. Joo, J. Kahn, K. H. Kang, H. Kichimi, C. Kiesling, C. H. Kim, D. Y. Kim, S. H. Kim, Y. -K. Kim, T. D. Kimmel, K. Kinoshita, P. Kodyš, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, P. Križan, R. Kroeger, P. Krokovny, T. Kuhr, R. Kulasiri, M. Kumar, R. Kumar, K. Kumara, A. Kuzmin, Y. -J. Kwon, S. C. Lee, C. H. Li. 2021-07-29. Measurement of Differential Branching Fractions of Inclusive ${B \to X_u \, \ell^+\, \nu_{\ell}}$ Decays. https://doi.org/10.1103/physrevlett.127.261801

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