Test of lepton flavor universality in $B \to K \ell^{+}\ell^{-}$ decays
Creators: name: Abdesselam, A.
name: Adachi, I.
name: Adamczyk, K.
name: Ahn, J. K.
name: Aihara, H.
name: Al Said, S.
name: Arinstein, K.
name: Arita, Y.
name: Asner, D. M.
name: Atmacan, H.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Aziz, T.
name: Babu, V.
name: Badhrees, I.
name: Bahinipati, S.
name: Bakich, A. M.
name: Ban, Y.
name: Bansal, V.
name: Barberio, E.
name: Barrett, M.
name: Bartel, W.
name: Behera, P.
name: Beleño, C.
name: Belous, K.
name: Bennett, J.
name: Berger, M.
name: Bernlochner, F.
name: Besson, D.
name: Bhardwaj, V.
name: Bhuyan, B.
name: Bilka, T.
name: Biswal, J.
name: Bloomfield, T.
name: Bobrov, A.
name: Bondar, A.
name: Bonvicini, G.
name: Bozek, A.
name: Bračko, M.
name: Braun, N.
name: Breibeck, F.
name: Browder, T. E.
name: Campajola, M.
name: Cao, L.
name: Caria, G.
name: Červenkov, D.
name: Chang, M.-C.
name: Chang, P.
name: Chao, Y.
name: Cheaib, R.
name: Chekelian, V.
name: Chen, A.
name: Chen, K.-F.
name: Chen, Y.
name: Cheon, B. G.
name: Chilikin, K.
name: Chistov, R.
name: Cho, H. E.
name: Cho, K.
name: Chobanova, V.
name: Choi, S.-K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Crnkovic, J.
name: Cunliffe, S.
name: Czank, T.
name: Danilov, M.
name: Dash, N.
name: De Nardo, G.
name: Di Carlo, S.
name: Di Capua, F.
name: Dingfelder, J.
name: Doležal, Z.
name: Dong, T. V.
name: Dossett, D.
name: Drásal, Z.
name: Drutskoy, A.
name: Dubey, S.
name: Dutta, D.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Feindt, M.
name: Ferber, T.
name: Frey, A.
name: Frost, O.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gelb, M.
name: Gemmler, J.
name: Getzkow, D.
name: Giordano, F.
name: Giri, A.
name: Goldenzweig, P.
name: Golob, B.
name: Greenwald, D.
name: Grosse Perdekamp, M.
name: Grygier, J.
name: Grzymkowska, O.
name: Guan, Y.
name: Guido, E.
name: Guo, H.
name: Haba, J.
name: Hamer, P.
name: Hara, K.
name: Hara, T.
name: Hartbrich, O.
name: Hasegawa, Y.
name: Hasenbusch, J.
name: Hayasaka, K.
name: Hayashii, H.
name: He, X. H.
name: Heck, M.
name: Hedges, M. T.
name: Heffernan, D.
name: Heider, M.
name: Heller, A.
name: Higuchi, T.
name: Hirose, S.
name: Hoshi, Y.
name: Hoshina, K.
name: Hou, W.-S.
name: Hsiung, Y. B.
name: Hsu, C.-L.
name: Huang, K.
name: Huschle, M.
name: Igarashi, Y.
name: Iijima, T.
name: Imamura, M.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Iwata, S.
name: Jacobs, W. W.
name: Jaegle, I.
name: Jang, E.-J.
name: Jeon, H. B.
name: Jia, S.
name: Jin, Y.
name: Joffe, D.
name: Jones, M.
name: Joo, C. W.
name: Joo, K. K.
name: Julius, T.
name: Kahn, J.
name: Kakuno, H.
name: Kaliyar, A. B.
name: Kang, J. H.
name: Kang, K. H.
name: Kapusta, P.
name: Karyan, G.
name: Kataoka, S. U.
name: Kato, Y.
name: Katrenko, P.
name: Kawai, H.
name: Kawasaki, T.
name: Keck, T.
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name: Kim, B. H.
name: Kim, C. H.
name: Kim, D. Y.
name: Kim, H. J.
name: Kim, H.-J.
name: Kim, J. B.
name: Kim, K. T.
name: Kim, S. H.
name: Kim, S. K.
name: Kim, Y. J.
name: Kimmel, T.
name: Kindo, H.
name: Kinoshita, K.
name: Kleinwort, C.
name: Klucar, J.
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name: Kodyš, P.
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name: Konno, T.
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name: Kotchetkov, D.
name: Kouzes, R. T.
name: Križan, P.
name: Kroeger, R.
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name: Krokovny, P.
name: Kronenbitter, B.
name: Kuhr, T.
name: Kulasiri, R.
name: Kumar, R.
name: Kumita, T.
name: Kurihara, E.
name: Kuroki, Y.
name: Kuzmin, A.
name: Kvasnička, P.
name: Kwon, Y.-J.
name: Lai, Y.-T.
name: Lalwani, K.
name: Lange, J. S.
name: Lee, I. S.
name: Lee, J. K.
name: Lee, J. Y.
name: Lee, S. C.
name: Leitgab, M.
name: Leitner, R.
name: Levit, D.
name: Lewis, P.
name: Li, C. H.
name: Li, H.
name: Li, L. K.
name: Li, Y.
name: Li, Y. B.
name: Li Gioi, L.
name: Libby, J.
name: Lieret, K.
name: Limosani, A.
name: Liptak, Z.
name: Liu, C.
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name: Liventsev, D.
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name: Lubej, M.
name: Luo, T.
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name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: McNeil, J. T.
name: Merola, M.
name: Metzner, F.
name: Miyabayashi, K.
name: Miyachi, Y.
name: Miyake, H.
name: Miyata, H.
name: Miyazaki, Y.
name: Mizuk, R.
name: Mohanty, G. B.
name: Mohanty, S.
name: Moon, H. K.
name: Moon, T. J.
name: Mori, T.
name: Morii, T.
name: Moser, H.-G.
name: Mrvar, M.
name: Müller, T.
name: Muramatsu, N.
name: Mussa, R.
name: Nagasaka, Y.
name: Nakahama, Y.
name: Nakamura, I.
name: Nakamura, K. R.
name: Nakano, E.
name: Nakano, T.
name: Nakao, M.
name: Nakayama, H.
name: Nakazawa, H.
name: Nanut, T.
name: Nath, K. J.
name: Natkaniec, Z.
name: Nayak, M.
name: Neichi, K.
name: Ng, C.
name: Niebuhr, Carsten
name: Niiyama, M.
name: Nisar, N. K.
name: Nishida, S.
name: Nishimura, K.
name: Nitoh, O.
name: Ogawa, A.
name: Ogawa, K.
name: Ogawa, S.
name: Ohshima, T.
name: Okuno, S.
name: Olsen, S. L.
name: Ono, H.
name: Onuki, Y.
name: Ostrowicz, W.
name: Oswald, C.
name: Ozaki, H.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pal, B.
name: Pang, T.
name: Panzenböck, E.
name: Pardi, S.
name: Park, C.-S.
name: Park, C. W.
name: Park, H.
name: Park, K. S.
name: Park, S.-H.
name: Patra, S.
name: Paul, S.
name: Pavelkin, I.
name: Pedlar, T. K.
name: Peng, T.
name: Pesántez, L.
name: Pestotnik, R.
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name: Vahsen, S. E.
name: Van Hulse, C.
name: Van Tonder, R.
name: Vanhoefer, P.
name: Varner, G.
name: Varvell, K. E.
name: Vervink, K.
name: Vinokurova, A.
name: Vorobyev, V.
name: Vossen, A.
name: Wagner, M. N.
name: Waheed, E.
name: Wang, B.
name: Wang, C. H.
name: Wang, M.-Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Watanabe, Y.
name: Watanuki, S.
name: Wedd, R.
name: Wehle, S.
name: Widmann, E.
name: Wiechczynski, J.
name: Williams, K. M.
name: Won, E.
name: Yabsley, B. D.
name: Yamada, S.
name: Yamamoto, H.
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name: Yashchenko, S.
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name: Yelton, J.
name: Yin, J. H.
name: Yook, Y.
name: Yuan, C. Z.
name: Yusa, Y.
name: Zakharov, S.
name: Zhang, C. C.
name: Zhang, J.
name: Zhang, L. M.
name: Zhang, Z. P.
name: Zhao, L.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
name: Zivko, T.
name: Zupanc, A.
name: Zwahlen, N.
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2020
Subjects: electron positron: annihilation
electron positron: colliding beams
B: pair production
B: semileptonic decay
muon: pair production
electron: pair production
branching ratio: ratio: measured
mass dependence
B: branching ratio: measured
lepton: flavor: universality
isospin: asymmetry
muon: final state
Upsilon(10570): electroproduction
statistical
dilepton: mass spectrum
BELLE
KEK-B
experimental results
B --&gt; K muon+ muon-
B --&gt; K electron positron

description: We present measurements of the branching fractions for the decays $B\to K \mu^{+}\mu^{-}$ 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 $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The ratio $R_{K}$ is measured in four bins of dilepton invariant-mass squared, $q^{2}$; the results are \begin{eqnarray*} R_{K} = \begin{cases} 0.95~ ^{+0.27}_{-0.24} \pm 0.06 &amp; q^{2} \in (0.1,4.0)~\mathrm{\,GeV^2}c^4 \, , 0.81~ ^{+0.28}_{-0.23} \pm 0.05 &amp; q^{2} \in (4.0,8.12)~\mathrm{\,GeV^2}c^4 \, , 0.98~ ^{+0.27}_{-0.23} \pm 0.06 &amp; q^{2} \in (1.0,6.0)~\mathrm{\,GeV^2}c^4 \, , 1.11~ ^{+0.29}_{-0.26} \pm 0.07 &amp; q^{2} &gt; 14.18~\mathrm{\,GeV^2}c^4 \, . \end{cases} \end{eqnarray*} The first uncertainties listed are statistical, and the second uncertainties are systematic. The $R_{K}$ value in the whole $q^2$ range is found to be $1.06~ ^{+0.15}_{-0.14} \pm 0.07$. We also measure $CP-$averaged isospin asymmetries in the same $q^{2}$ bins; the results are consistent with a null asymmetry with the largest difference of 2.7 standard deviations is found in the $q^{2}\in(1.0,6.0)~\mathrm{\,GeV^2}c^4 \,$ bin in the mode with muon final states. The measured branching fractions are $\cal B\rm{\it(B\to K \mu^{+}\mu^{-})}= (5.5 \pm0.5 \pm0.3) \times 10^{-7}$ and $\cal B\rm{\it(B\to K e^{+}e^{-})} = (5.1 \pm 0.5 \pm0.3) \times 10^{-7}$. These results are compatible with standard model expectations.