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 Bracko; T E Browder; Y-W Chang; Y Chao; A Chen; K-F Chen; B G Cheon; C-C Chiang; I-S Cho; Y 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 Krizan; 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 Stanic; M Staric; 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; Belle Collaboration

doi:10.1103/PhysRevLett.103.171801

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

Phys Rev Lett. 2009 Oct 23;103(17):171801. doi: 10.1103/PhysRevLett.103.171801. Epub 2009 Oct 20.

Authors

J-T Wei¹, P Chang, I Adachi, H Aihara, V Aulchenko, T Aushev, A M Bakich, V Balagura, E Barberio, A Bondar, A Bozek, M Bracko, T E Browder, Y-W Chang, Y Chao, A Chen, K-F Chen, B G Cheon, C-C Chiang, I-S Cho, Y 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 Krizan, 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 Stanic, M Staric, 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; Belle Collaboration

Affiliation

¹ Department of Physics, National Taiwan University, Taipei.

PMID: 19905747
DOI: 10.1103/PhysRevLett.103.171801

Abstract

We study B --> K(*)l+l- decays (l = e, mu) based on a data sample of 657 x 10(6) BB 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 (A(FB)) as functions of q2 = M(ll)(2)c2. The fitted A(FB) 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) x 10(-7) and B(B --> Kl+l-) = (4.8(-0.4)(+0.5) +/- 0.3) x 10(-7), where the first errors are statistical and the second are systematic, with the muon to electron ratios R(K*) = 0.83 +/- 0.17 +/- 0.08 and R(K) = 1.03 +/- 0.19 +/- 0.06.