Test of lepton flavor universality and search for lepton flavor violation in $B \to K \ell\ell$ decays
Creators: name: Choudhury, S.
name: Sandilya, S.
name: Trabelsi, K.
name: Giri, A.
name: Aihara, H.
name: Said, S. Al
name: Asner, D. M.
name: Atmacan, H.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Bahinipati, S.
name: Behera, P.
name: Beleño, C.
name: Belous, K.
name: Bennett, J.
name: Bernlochner, F.
name: Bessner, M.
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, M. -C.
name: Chang, P.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Choi, S. -K.
name: Choi, Y.
name: Cinabro, D.
name: Cunliffe, S.
name: Dash, N.
name: De Nardo, G.
name: Dhamija, R.
name: Di Capua, F.
name: Dingfelder, J.
name: Doležal, Z.
name: Dong, T. V.
name: Dossett, D.
name: Dubey, S.
name: Eidelman, S.
name: Epifanov, D.
name: Ferber, T.
name: Ferlewicz, D.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Goldenzweig, P.
name: Golob, B.
name: Greenwald, D.
name: Hadjivasiliou, C.
name: Hartbrich, O.
name: Hayashii, H.
name: Hedges, M. T.
name: Villanueva, M. Hernandez
name: Higuchi, T.
name: Hou, W. -S.
name: Hsu, C. -L.
name: Iijima, T.
name: Inami, K.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jang, E. -J.
name: Jeon, H. B.
name: Jia, S.
name: Jin, Y.
name: Joo, C. W.
name: Joo, K. K.
name: Kahn, J.
name: Kaliyar, A. B.
name: Kang, K. H.
name: Karyan, G.
name: Kichimi, H.
name: Kiesling, C.
name: Kim, B. H.
name: Kim, D. Y.
name: Kim, K. -H.
name: Kim, K. T.
name: Kim, S. H.
name: Kim, Y. -K.
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: Kumara, K.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lalwani, K.
name: Lee, S. C.
name: Lewis, P.
name: Li, C. H.
name: Li, L. K.
name: Li, Y. B.
name: Gioi, L. Li
name: Libby, J.
name: Lieret, K.
name: Liptak, Z.
name: Liventsev, D.
name: Luo, T.
name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: Merola, M.
name: Miyabayashi, K.
name: Mizuk, R.
name: Mohanty, G. B.
name: Mohanty, S.
name: Moon, T. J.
name: Mori, T.
name: Nakamura, I.
name: Nakamura, K. R.
name: Nakao, M.
name: Natkaniec, Z.
name: Natochii, A.
name: Nayak, L.
name: Nayak, M.
name: Niiyama, M.
name: Nisar, N. K.
name: Nishida, S.
name: Ogawa, K.
name: Ono, H.
name: Onuki, Y.
name: Oskin, P.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pardi, S.
name: Park, H.
name: Park, S. -H.
name: Patra, S.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Podobnik, T.
name: Popov, V.
name: Prencipe, E.
name: Prim, M. T.
name: Rabusov, A.
name: Rostomyan, A.
name: Rout, N.
name: Rozanska, M.
name: Russo, G.
name: Sahoo, D.
name: Sakai, Y.
name: Santelj, L.
name: Sanuki, T.
name: Savinov, V.
name: Schnell, G.
name: Schueler, J.
name: Schwanda, C.
name: Schwartz, A. J.
name: Seino, Y.
name: Senyo, K.
name: Sevior, M. E.
name: Shapkin, M.
name: Shebalin, V.
name: Shiu, J. -G.
name: Shwartz, B.
name: Simon, F.
name: Sokolov, A.
name: Solovieva, E.
name: Stanič, S.
name: Starič, M.
name: Stottler, Z. S.
name: Sumiyoshi, T.
name: Sutcliffe, W.
name: Takizawa, M.
name: Tamponi, U.
name: Tanida, K.
name: Tenchini, F.
name: Uchida, M.
name: Uehara, S.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Urquijo, P.
name: Ushiroda, Y.
name: Van Tonder, R.
name: Varner, G.
name: Varvell, K. E.
name: Vinokurova, A.
name: Vorobyev, V.
name: Waheed, E.
name: Wang, C. H.
name: Wang, E.
name: Wang, M. -Z.
name: Wang, P.
name: Watanabe, M.
name: Watanuki, S.
name: Wehle, S.
name: Wiechczynski, J.
name: Won, E.
name: Xu, X.
name: Yabsley, B. D.
name: Yan, W.
name: Yang, S. B.
name: Ye, H.
name: Yelton, J.
name: Yin, J. H.
name: Yuan, C. Z.
name: Yusa, Y.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
Publisher: name: arXiv
Year: 2019
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present measurements of the branching fractions for the decays $B\to K μ^{+}μ^{-}$ and $B\to K e^{+}e^{-}$, and their ratio ($R_{K}$), using a data sample of 711 $fb^{-1}$ that contains $772 \times 10^{6}$ $B\bar{B}$ events. The data were collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The ratio $R_{K}$ is measured in five bins of dilepton invariant-mass-squared ($q^{2}$): $q^{2} \in (0.1, 4.0), (4.0, 8.12), (1.0, 6.0)$, $(10.2, 12.8)$ and ($&gt;14.18) GeV^{2}/c^{4}$, along with the whole $q^2$ region. The $R_{K}$ value for $q^{2} \in (1.0, 6.0) GeV^{2}/c^{4}$ is $1.03^{+0.28}_{-0.24} \pm 0.01$. The first and second uncertainties listed are statistical and systematic, respectively. All results for $R_{K}$ are consistent with Standard Model predictions. We also measure $C\!P$-averaged isospin asymmetries in the same $q^{2}$ bins. The results are consistent with a null asymmetry, with the largest difference of 2.6 standard deviations occurring for the $q^{2}\in(1.0,6.0) GeV^{2}/c^{4}$ bin in the mode with muon final states. The measured differential branching fractions, ${d\cal B}/{dq^{2}}$, are consistent with theoretical predictions for charged $B$ decays, while the corresponding values are below the expectations for neutral $B$ decays. We have also searched for lepton-flavor-violating $B \rightarrow Kμ^{\pm}e^{\mp}$ decays and set $90\%$ confidence-level upper limits on the branching fraction in the range of $10^{-8}$ for $B^{+} \rightarrow K^{+}μ^{\pm}e^{\mp}$, and $B^{0} \rightarrow K^{0}μ^{\pm}e^{\mp}$ modes.
description: 18 pages, 7 figures