Measurement of the inclusive semileptonic branching fraction $\mathcal{B}(B_s^0 \rightarrow X^- \ell^+ ν_\ell)$ at Belle

Belle Collaboration, C. Oswald, P. Urquijo, J. Dingfelder, I. Adachi, H. Aihara, K. Arinstein, D. M. Asner, T. Aushev, A. M. Bakich, K. Belous, V. Bhardwaj, B. Bhuyan, A. Bondar, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, P. Chang, V. Chekelian, A. Chen, P. Chen, B. G. Cheon, K. Chilikin, R. Chistov, K. Cho, V. Chobanova, S. -K. Choi, Y. Choi, D. Cinabro, J. Dalseno, Z. Doležal, Z. Drásal, A. Drutskoy, D. Dutta, S. Eidelman, S. Esen, H. Farhat, J. E. Fast, V. Gaur, N. Gabyshev, S. Ganguly, R. Gillard, Y. M. Goh, B. Golob, J. Haba, K. Hayasaka, H. Hayashii, Y. Horii, Y. Hoshi, W. -S. Hou, H. J. Hyun, T. Iijima, A. Ishikawa, R. Itoh, Y. Iwasaki, D. H. Kah, J. H. Kang, E. Kato, T. Kawasaki, C. Kiesling, H. J. Kim, H. O. Kim, J. B. Kim, K. T. Kim, M. J. Kim, Y. J. Kim, K. Kinoshita, J. Klucar, B. R. Ko, S. Korpar, R. T. Kouzes, P. Križan, P. Krokovny, B. Kronenbitter, T. Kuhr, T. Kumita, Y. -J. Kwon, S. -H. Lee, J. Li, Y. Li, J. Libby, C. Liu, Y. Liu, Z. Q. Liu, D. Liventsev, R. Louvot, O. Lutz, D. Matvienko, K. Miyabayashi, H. Miyata, R. Mizuk, G. B. Mohanty, A. Moll, N. Muramatsu, Y. Nagasaka, E. Nakano, M. Nakao, E. Nedelkovska, N. K. Nisar, S. Nishida, O. Nitoh, T. Nozaki, S. Ogawa, T. Ohshima, S. Okuno, S. L. Olsen, W. Ostrowicz, P. Pakhlov, G. Pakhlova, H. Park, H. K. Park, T. K. Pedlar, R. Pestotnik, M. Petrič, L. E. Piilonen, M. Prim, K. Prothmann, M. Ritter, M. Röhrken, M. Rozanska, S. Ryu, H. Sahoo, T. Saito, Y. Sakai, S. Sandilya, L. Santelj, T. Sanuki, Y. Sato, O. Schneider, G. Schnell, C. Schwanda, A. J. Schwartz, K. Senyo, O. Seon, M. E. Sevior, M. Shapkin, C. P. Shen, T. -A. Shibata, J. -G. Shiu, B. Shwartz, A. Sibidanov, F. Simon, P. Smerkol, Y. -S. Sohn, A. Sokolov, E. Solovieva, M. Starič, T. Sumiyoshi, G. Tatishvili, Y. Teramoto, K. Trabelsi, T. Tsuboyama, M. Uchida, S. Uehara, T. Uglov, Y. Unno, S. Uno, C. Van Hulse, P. Vanhoefer, G. Varner, K. E. Varvell, C. H. Wang, M. -Z. Wang, P. Wang, M. Watanabe, Y. Watanabe, K. M. Williams, E. Won, H. Yamamoto, Y. Yamashita, C. C. Zhang, Z. P. Zhang, V. Zhilich, A. Zupanc

Published 2012-12-27, updated 2014-10-02Version 4

We report a measurement of the inclusive semileptonic $B_s^0$ branching fraction in a $121~fb^{-1}$ data sample collected near the $\Upsilon(5S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. Events containing $B_s^0$ pairs are selected by reconstructing a tag side $D_s^+$ and identifying a signal side lepton $\ell^+$ ($\ell = e, \mu$) that is required to have the same-sign charge to ensure that both originate from different $B_s^0$ mesons. The $B_s^0 \rightarrow X^- \ell^+ \nu_\ell$ branching fraction is extracted from the ratio of the measured yields of $D_s^+$ mesons and $D_s^+ \ell^+$ pairs and the known production and branching fractions. The inclusive semileptonic branching fraction is measured to be $[9.6 \pm 0.4\text{(stat)} \pm 0.7\text{(syst)}]~\%$.