Measurement of Differential Distributions of $B \to D^* \ell \bar ν_\ell$ and Implications on $|V_{cb}|$

Belle Collaboration, M. T. Prim, F. Bernlochner, F. Metzner, K. Lieret, T. Kuhr, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, Sw. Banerjee, M. Bauer, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, D. Biswas, D. Bodrov, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, L. Cao, D. Červenkov, M. -C. Chang, V. Chekelian, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, Y. Choi, S. Choudhury, D. Cinabro, S. Das, N. Dash, G. de Marino, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, D. Epifanov, T. Ferber, D. Ferlewicz, A. Frey, B. G. Fulsom, V. Gaur, A. Garmash, A. Giri, P. Goldenzweig, E. Graziani, T. Gu, K. Gudkova, C. Hadjivasiliou, S. Halder, T. Hara, K. Hayasaka, H. Hayashii, M. T. Hedges, D. Herrmann, M. Hernández Villanueva, C. -L. Hsu, T. Iijima, K. Inami, G. Inguglia, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, W. W. Jacobs, E. -J. Jang, S. Jia, Y. Jin, K. K. Joo, A. B. Kaliyar, K. H. Kang, T. Kawasaki, C. Kiesling, C. H. Kim, D. Y. Kim, K. -H. Kim, Y. -K. Kim, K. Kinoshita, P. Kodyš, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, P. Križan, P. Krokovny, M. Kumar, R. Kumar, K. Kumara, A. Kuzmin, Y. -J. Kwon, K. Lalwani, J. S. Lange, M. Laurenza, S. C. Lee, P. Lewis, J. Li, L. K. Li, Y. Li, J. Libby, Y. -R. Lin, D. Liventsev, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, S. K. Maurya, F. Meier, M. Merola, K. Miyabayashi, R. Mizuk, G. B. Mohanty, I. Nakamura, M. Nakao, Z. Natkaniec, A. Natochii, L. Nayak, N. K. Nisar, S. Nishida, K. Ogawa, S. Ogawa, H. Ono, P. Oskin, P. Pakhlov, G. Pakhlova, T. Pang, S. Pardi, H. Park, J. Park, S. -H. Park, A. Passeri, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, E. Prencipe, A. Rabusov, M. Röhrken, A. Rostomyan, N. Rout, G. Russo, S. Sandilya, A. Sangal, L. Santelj, V. Savinov, G. Schnell, C. Schwanda, A. J. Schwartz, Y. Seino, K. Senyo, M. E. Sevior, W. Shan, M. Shapkin, C. Sharma, J. -G. Shiu, B. Shwartz, F. Simon, A. Soffer, A. Sokolov, E. Solovieva, M. Starič, M. Sumihama, T. Sumiyoshi, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, K. Trabelsi, T. Uglov, Y. Unno, S. Uno, P. Urquijo, Y. Usov, S. E. Vahsen, R. van Tonder, G. Varner, K. E. Varvell, A. Vinokurova, A. Vossen, E. Waheed, D. Wang, M. -Z. Wang, M. Watanabe, S. Watanuki, E. Won, B. D. Yabsley, W. Yan, S. B. Yang, J. Yelton, Y. Yook, C. Z. Yuan, L. Yuan, Y. Yusa, Y. Zhai, Z. P. Zhang, V. Zhilich, V. Zhukova

Published 2023-01-18Version 1

We present a measurement of the differential shapes of exclusive $B\to D^* \ell \bar{\nu}_\ell$ ($B = B^-, \bar{B}^0 $ and $\ell = e, \mu$) decays with hadronic tag-side reconstruction for the full Belle data set of $711\,\mathrm{fb}^{-1}$ integrated luminosity. We extract the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) form factor parameters and use an external input for the absolute branching fractions to determine the Cabibbo-Kobayashi-Maskawa matrix element and find $|V_{cb}|_\mathrm{CLN} = (40.1\pm0.9)\times 10^{-3}$ and $|V_{cb}|_\mathrm{BGL} = (40.6\pm 0.9)\times 10^{-3}$ with the zero-recoil lattice QCD point $\mathcal{F}(1) = 0.906 \pm 0.013$. We also perform a study of the impact of preliminary beyond zero-recoil lattice QCD calculations on the $|V_{cb}|$ determinations. Additionally, we present the lepton flavor universality ratio $R_{e\mu} = \mathcal{B}(B \to D^* e \bar{\nu}_e) / \mathcal{B}(B \to D^* \mu \bar{\nu}_\mu) = 0.990 \pm 0.021 \pm 0.023$, the electron and muon forward-backward asymmetry and their difference $\Delta A_{FB}=0.022\pm0.026\pm 0.007$, and the electron and muon $D^*$ longitudinal polarization fraction and their difference $\Delta F_L^{D^*} = 0.034 \pm 0.024 \pm 0.007$. The uncertainties quoted correspond to the statistical and systematic uncertainties, respectively.