Measurement of the Branching Fraction of the Decay $\boldsymbol{B^{+}\toπ^{+}π^{-}\ell^{+}ν_\ell}$ in Fully Reconstructed Events at Belle
Creators: name: The Belle Collaboration
name: Beleño, C.
name: Frey, A.
name: Adachi, I.
name: Aihara, H.
name: Asner, D. M.
name: Atmacan, H.
name: Aushev, T.
name: Ayad, R.
name: Behera, P.
name: Bennett, J.
name: Bernlochner, F.
name: Bhardwaj, V.
name: Bilka, T.
name: Biswal, J.
name: Bonvicini, G.
name: Bozek, A.
name: Bračko, M.
name: Browder, T. E.
name: Campajola, M.
name: Červenkov, D.
name: Chang, P.
name: Chen, A.
name: Chilikin, K.
name: Cho, K.
name: Choi, Y.
name: Cinabro, D.
name: Cunliffe, S.
name: Dash, N.
name: Di Capua, F.
name: Dingfelder, J.
name: Doležal, Z.
name: Dong, T. V.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Ferber, T.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Giri, A.
name: Goldenzweig, P.
name: Guan, Y.
name: Hartbrich, O.
name: Hayasaka, K.
name: Hayashii, H.
name: Hou, W. -S.
name: Inami, K.
name: Ishikawa, A.
name: Iwasaki, M.
name: Jacobs, W. W.
name: Jeon, H. B.
name: Jin, Y.
name: Joo, K. K.
name: Kiesling, C.
name: Kim, B. H.
name: Kim, D. Y.
name: Kim, K. -H.
name: Kim, S. H.
name: Kim, Y. -K.
name: Kimmel, T. D.
name: Kinoshita, K.
name: Kodyš, P.
name: Korpar, S.
name: Kotchetkov, D.
name: Križan, P.
name: Kroeger, R.
name: Krokovny, P.
name: Kuhr, T.
name: Kulasiri, R.
name: Kumar, R.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lalwani, K.
name: Lee, S. C.
name: Li, L. K.
name: Li, Y. B.
name: Gioi, L. Li
name: Libby, J.
name: Lieret, K.
name: Liventsev, D.
name: Luo, T.
name: MacNaughton, J.
name: MacQueen, C.
name: Masuda, M.
name: Matsuda, T.
name: Merola, M.
name: Miyabayashi, K.
name: Mohanty, G. B.
name: Moon, T. J.
name: Mori, T.
name: Mrvar, M.
name: Nakao, M.
name: Nisar, N. K.
name: Nishida, S.
name: Ogawa, S.
name: Ono, H.
name: Oskin, P.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pardi, S.
name: Park, H.
name: Patra, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Podobnik, T.
name: Prencipe, E.
name: Prim, M. T.
name: Rostomyan, A.
name: Rout, N.
name: Russo, G.
name: Sahoo, D.
name: Sakai, Y.
name: Sandilya, S.
name: Sangal, A.
name: Sanuki, T.
name: Savinov, V.
name: Schnell, G.
name: Schwanda, C.
name: Schwartz, A. J.
name: Schwenker, B.
name: Seino, Y.
name: Senyo, K.
name: Sevior, M. E.
name: Shapkin, M.
name: Shiu, J. -G.
name: Shwartz, B.
name: Sokolov, A.
name: Solovieva, E.
name: Starič, M.
name: Stottler, Z. S.
name: Strube, J. F.
name: Sumiyoshi, T.
name: Sutcliffe, W.
name: Takizawa, M.
name: Tanida, K.
name: Tenchini, F.
name: Uchida, M.
name: Uglov, T.
name: Uno, S.
name: Urquijo, P.
name: Vahsen, S. E.
name: Van Tonder, R.
name: Varner, G.
name: Varvell, K. E.
name: Wang, C. H.
name: Wang, E.
name: Wang, M. -Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Won, E.
name: Xu, X.
name: Yan, W.
name: Yang, S. B.
name: Ye, H.
name: Yusa, Y.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present an analysis of the exclusive $B^{+}\toπ^{+}π^{-}\ell^{+}ν_{\ell}$ decay, where $\ell$ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The analysis uses the full $Υ(4S)$ data sample collected by the Belle detector, corresponding to 711 fb$^{-1}$ of integrated luminosity. We select the events by fully reconstructing one $B$ meson in hadronic decay modes, subsequently determining the properties of the other $B$ meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of ${{\cal B}(B^{+}\to π^{+}π^{-}\ell^{+}ν_{\ell})= [22.7 ^{+1.9}_{-1.6} (\mathrm{stat}) \pm 3.5(\mathrm{syst}) ]\times 10^{-5}}$, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay.
description: 23 pages, 19 figures