Measurement of the differential branching fraction and forward-backward asymmetry for b→K(*)l+l-

J. T. Wei, P. Chang, I. Adachi, H. Aihara, V. Aulchenko, T. Aushev, A. M. Bakich, V. Balagura, E. Barberio, A. Bondar, A. Bozek, M. Bračko, T. E. Browder, Y. W. Chang, Y. Chao, A. Chen, K. F. Chen, B. G. Cheon, C. C. Chiang, I. S. ChoY. Choi, J. Dalseno, A. Drutskoy, W. Dungel, S. Eidelman, N. Gabyshev, P. Goldenzweig, B. Golob, H. Ha, B. Y. Han, K. Hayasaka, H. Hayashii, M. Hazumi, Y. Horii, Y. Hoshi, W. S. Hou, H. J. Hyun, T. Iijima, K. Inami, R. Itoh, M. Iwasaki, Y. Iwasaki, D. H. Kah, H. Kaji, J. H. Kang, P. Kapusta, N. Katayama, T. Kawasaki, H. Kichimi, H. J. Kim, H. O. Kim, S. K. Kim, Y. I. Kim, Y. J. Kim, K. Kinoshita, B. R. Ko, S. Korpar, P. Križan, P. Krokovny, A. Kuzmin, Y. J. Kwon, S. H. Kyeong, J. S. Lange, M. J. Lee, S. E. Lee, T. Lesiak, J. Li, A. Limosani, C. Liu, D. Liventsev, R. Louvot, F. Mandl, A. Matyja, S. McOnie, T. Medvedeva, K. Miyabayashi, H. Miyata, Y. Miyazaki, R. Mizuk, E. Nakano, M. Nakao, H. Nakazawa, Z. Natkaniec, S. Nishida, K. Nishimura, O. Nitoh, T. Nozaki, S. Ogawa, T. Ohshima, S. Okuno, H. Ozaki, G. Pakhlova, C. W. Park, H. Park, H. K. Park, K. S. Park, L. E. Piilonen, M. Rozanska, H. Sahoo, K. Sakai, Y. Sakai, O. Schneider, C. Schwanda, A. J. Schwartz, R. Seidl, A. Sekiya, K. Senyo, M. E. Sevior, M. Shapkin, C. P. Shen, J. G. Shiu, B. Shwartz, S. Stanič, M. Starič, T. Sumiyoshi, S. Suzuki, M. Tanaka, G. N. Taylor, Y. Teramoto, K. Trabelsi, S. Uehara, T. Uglov, Y. Unno, S. Uno, P. Urquijo, Y. Usov, G. Varner, K. E. Varvell, K. Vervink, C. C. Wang, C. H. Wang, M. Z. Wang, P. Wang, X. L. Wang, Y. Watanabe, R. Wedd, J. Wicht, E. Won, B. D. Yabsley, Y. Yamashita, M. Yamauchi, C. Z. Yuan, Z. P. Zhang, T. Zivko, A. Zupanc, O. Zyukova

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Abstract

We study B→K(*)ℓ+ℓ- decays (ℓ=e, μ) based on a data sample of 657×106 BB̄ pairs collected with the Belle detector at the KEKB e+e- collider. We report the differential branching fraction, isospin asymmetry, K* polarization, and the forward-backward asymmetry (AFB) as functions of q2=Mℓ2c2. The fitted AFB spectrum exceeds the standard model expectation by 2.7 standard deviations. The measured branching fractions are B(B→K*ℓ+ℓ-)=(10.7-1.0+1.1±0.9)×10-7 and B(B→Kℓ+ℓ-)=(4.8-0.4+0.5±0.3)×10-7, where the first errors are statistical and the second are systematic, with the muon to electron ratios RK*=0.83±0.17±0.08 and RK=1.03±0.19±0. 06.

Original languageEnglish
Article number171801
JournalPhysical review letters
Volume103
Issue number17
DOIs
Publication statusPublished - 2009 Oct 20

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Wei, J. T., Chang, P., Adachi, I., Aihara, H., Aulchenko, V., Aushev, T., Bakich, A. M., Balagura, V., Barberio, E., Bondar, A., Bozek, A., Bračko, M., Browder, T. E., Chang, Y. W., Chao, Y., Chen, A., Chen, K. F., Cheon, B. G., Chiang, C. C., ... Zyukova, O. (2009). Measurement of the differential branching fraction and forward-backward asymmetry for b→K(*)l+l-. Physical review letters, 103(17), [171801]. https://doi.org/10.1103/PhysRevLett.103.171801