Artigo Acesso aberto

Improved measurement of the electroweak penguin process B → X s ℓ + ℓ −

2005; American Physical Society; Volume: 72; Issue: 9 Linguagem: Inglês

10.1103/physrevd.72.092005

ISSN

1550-7998

Autores

M. Iwasaki, K. Itoh, H. Aihara, K. Abe, K. Abe, I. Adachi, Y. Asano, T. Aushev, S. Bahinipati, A. M. Bakich, S. Banerjee, I. Bedny, U. Bitenc, I. Bizjak, S. Blyth, A. Bondar, A. Bożek, M. Bračko, J. Brodzicka, T. E. Browder, M.-C. Chang, P. Chang, Y. Chao, K. F. Chen, K. F. Chen, W. T. Chen, B. G. Cheon, R. Chistov, S.-K. Choi, Y. Choi, A. Chuvikov, J. Dalseno, M. Danilov, M. Dash, A. Drutskoy, S. Eidelman, Y. Enari, S. Fratina, N. Gabyshev, T. Gershon, G. Gokhroo, B. Golob, A. Gorišek, J. Haba, T. Hara, N. C. Hastings, K. Hayasaka, H. Hayashii, M. Hazumi, T. Hokuue, Y. Hoshi, S. Hou, W.-S. Hou, Y. Hsiung, T. Iijima, A. Imoto, K. Inami, A. Ishikawa, H. Ishino, R. Itoh, J. H. Kang, J. S. Kang, N. Katayama, H. Kawai, T. Kawasaki, H. R. Khan, H. Kichimi, H. J. Kim, S. K. Kim, S. M. Kim, K. Kinoshita, P. Križan, P. Krokovny, R. Kulasiri, S. Kumar, C. C. Kuo, A. Kuzmin, Y.-J. Kwon, J. S. Lange, G. Leder, S. E. Lee, T. Lesiak, J. Li, S.-W. Lin, D. Liventsev, J. MacNaughton, G. Majumder, F. Mandl, T. Matsumoto, A. Matyja, Y. Mikami, W. Mitaroff, K. Miyabayashi, H. Miyake, H. Miyata, R. Mizuk, D. Mohapatra, G. R. Moloney, T. Nagamine, Y. Nagasaka, I. Nakamura, E. Nakano, M. Nakao, H. Nakazawa, Z. Natkaniec, S. Nishida, O. Nitoh, S. Ogawa, T. Ohshima, Toshitaka Okabe, S. Okuno, S. L. Olsen, W. Ostrowicz, H. Ozaki, H. Pałka, C. W. Park, H. Park, N. Parslow, L. S. Peak, R. Pestotnik, L. E. Piilonen, N. Root, M. Różańska, H. Sagawa, Y. Sakai, N. Sato, T. Schietinger, O. Schneider, P. Schönmeier, J. Schümann, C. Schwanda, A. J. Schwartz, M. E. Sevior, H. Shibuya, B. Shwartz, V. Sidorov, J. B. Singh, A. Somov, N. Soni, R. Stamen, S. Stanič, M. Starič, K. Sumisawa, T. Sumiyoshi, S. Suzuki, S. Suzuki, O. Tajima, F. Takasaki, K. Tamai, N. Tamura, M. Tanaka, G. N. Taylor, Y. Teramoto, X. C. Tian, T. Tsukamoto, S. Uehara, T. Uglov, K. Ueno, S. Uno, P. Urquijo, Y. Ushiroda, G. Varner, K. E. Varvell, S. Villà, C. C. Wang, C. H. Wang, M.-Z. Wang, Y. Watanabe, Q. L. Xie, B. Yabsley, Atsuko Yamaguchi, Y. Yamashita, M. Yamauchi, Heyoung Yang, J. Ying, L. M. Zhang, Z. P. Zhang, V. Zhilich, D. Žontar, D. Zürcher,

Tópico(s)

Atomic and Subatomic Physics Research

Resumo

We present an improved measurement of the branching fraction for the electroweak penguin process $B\ensuremath{\rightarrow}{X}_{s}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where $\ensuremath{\ell}$ is an electron or a muon and ${X}_{s}$ is a hadronic system containing an $s$-quark. The measurement is based on a sample of $152\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ events collected with the Belle detector at the KEKB energy asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. The ${X}_{s}$ hadronic system is reconstructed from one ${K}^{\ifmmode\pm\else\textpm\fi{}}$ or ${K}_{\mathrm{S}}^{0}$ and up to four pions, where at most one pion can be neutral. Averaging over both lepton flavors, the inclusive branching fraction is measured to be $\mathcal{B}(B\ensuremath{\rightarrow}{X}_{s}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})=(4.11\ifmmode\pm\else\textpm\fi{}0.83(\mathrm{stat}{)}_{\ensuremath{-}0.81}^{+0.85}(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ for ${M}_{{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}}>0.2\text{ }\mathrm{GeV}/{c}^{2}$.

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