Search for the rare decay of $B^+ \to \ell^{\,+} \nu_{\ell} \gamma$ with improved hadronic tagging
Creators: name: Gelb, M.
name: Bernlochner, F. U.
name: Goldenzweig, P.
name: Metzner, F.
name: Adachi, I.
name: Aihara, H.
name: Al Said, S.
name: Asner, D. M.
name: Atmacan, H.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Badhrees, I.
name: Bansal, V.
name: Behera, P.
name: Beleño, C.
name: Bhuyan, B.
name: Biswal, J.
name: Bobrov, A.
name: Bračko, M.
name: Braun, N.
name: Cao, L.
name: Červenkov, D.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Choi, S.-K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Cunliffe, S.
name: Dash, N.
name: Di Carlo, S.
name: Doležal, Z.
name: Dong, T. V.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Ferber, T.
name: Frey, A.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gemmler, J.
name: Giri, A.
name: Greenwald, D.
name: Haba, J.
name: Hara, T.
name: Hayasaka, K.
name: Hayashii, H.
name: Hou, W.-S.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jia, S.
name: Jin, Y.
name: Joffe, D.
name: Joo, K. K.
name: Kahn, J.
name: Kaliyar, A. B.
name: Kawasaki, T.
name: Kichimi, H.
name: Kiesling, C.
name: Kim, D. Y.
name: Kim, H. J.
name: Kim, S. H.
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: Kuzmin, A.
name: Kwon, Y.-J.
name: Lange, J. S.
name: Lee, I. S.
name: Lee, J. K.
name: Lee, J. Y.
name: Lee, S. C.
name: Li, Y. B.
name: Li Gioi, L.
name: Libby, J.
name: Liventsev, D.
name: Lu, P.-C.
name: Lubej, M.
name: Luo, T.
name: MacNaughton, J.
name: Masuda, M.
name: Merola, M.
name: Miyabayashi, K.
name: Miyata, H.
name: Mizuk, R.
name: Mohanty, G. B.
name: Mori, T.
name: Mrvar, M.
name: Mussa, R.
name: Nakao, M.
name: Nath, K. J.
name: Natkaniec, Z.
name: Nayak, M.
name: Niiyama, M.
name: Nisar, N. K.
name: Nishida, S.
name: Ogawa, S.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pal, B.
name: Pardi, S.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Popov, V.
name: Prencipe, E.
name: Prim, M.
name: Ritter, M.
name: Rostomyan, A.
name: Russo, G.
name: Sahoo, D.
name: Sakai, Y.
name: Salehi, M.
name: Sandilya, S.
name: Santelj, L.
name: Sanuki, T.
name: Savinov, V.
name: Schneider, O.
name: Schnell, G.
name: Schueler, J.
name: Schwanda, C.
name: Seino, Y.
name: Senyo, K.
name: Seon, O.
name: Sevior, M. E.
name: Shen, C. P.
name: Shibata, T.-A.
name: Shiu, J.-G.
name: Shwartz, B.
name: Simon, F.
name: Solovieva, E.
name: Stanič, S.
name: Starič, M.
name: Strube, J. F.
name: Sumihama, M.
name: Sumiyoshi, T.
name: Sutcliffe, W.
name: Takizawa, M.
name: Tanida, K.
name: Tao, Y.
name: Tenchini, F.
name: Uchida, M.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Urquijo, P.
name: Van Tonder, R.
name: Varner, G.
name: Varvell, K. E.
name: Wang, B.
name: Wang, C. H.
name: Wang, M.-Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Watanuki, S.
name: Widmann, E.
name: Won, E.
name: Yamamoto, H.
name: Yang, S. B.
name: Ye, H.
name: Yin, J. H.
name: Yuan, C. Z.
name: Yusa, Y.
name: Zakharov, S.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2018
Subjects: electron positron: annihilation
electron positron: colliding beams
B+: radiative decay
distribution amplitude: light cone
B+: branching ratio: upper limit
electron: final state
muon: final state
photon: energy
signature
Upsilon(10570): electroproduction
missing-mass
suppression
performance
background
B+: rare decay
kinematics
statistical analysis: Bayesian
moment
BELLE
KEK-B
data analysis method
experimental results
B+ --&gt; positron neutrino/e photon
B+ --&gt; muon+ neutrino/mu photon

description: We present the result of the search for the rare $B$ meson decay of $B^+ \to \ell^{\,+} \nu_{\ell} \gamma$ with $\ell =e,\mu$. For the search the full data set recorded by the Belle experiment of $711 \, \mathrm{fb}^{-1}$ integrated luminosity near the $\Upsilon (4S)$ resonance is used. Signal candidates are reconstructed for photon energies $E_{\gamma}$ larger than $1 \, \mathrm{GeV}$ using a novel multivariate tagging algorithm. The novel algorithm fully reconstructs the second $B$ meson produced in the collision using hadronic modes and was specifically trained to recognize the signal signature in combination with hadronic tag-side $B$ meson decays. This approach greatly enhances the performance. Background processes that can mimic this signature, mainly charmless semileptonic decays and continuum processes, are suppressed using multivariate methods. The number of signal candidates is determined by analyzing the missing mass squared distribution as inferred from the signal side particles and the kinematic properties of the tag-side $B$ meson. No significant excess over the background-only hypothesis is observed and upper limits on the partial branching fraction $ \Delta \mathcal{B} $ with $E_{\gamma}&gt; 1 \, \mathrm{GeV}$ individually for electron and muon final states as well as for the average branching fraction of both lepton final states are reported. We find a Bayesian upper limit of $\Delta \mathcal{B}( B^{+} \to \ell^{\, +} \nu_{\ell} \gamma) &lt; 3.0 \times 10^{-6}$ at 90% CL and also report an upper limit on the first inverse moment of the light-cone distribution amplitude of the $B$ meson of $\lambda_B$ at 90% CL.