Improved evidence for direct CP violation in B0→π+π- decays and model-independent constraints on 2

K. Abe, I. Adachi, H. Aihara, K. Arinstein, Y. Asano, T. Aushev, A. M. Bakich, Y. Ban, E. Barberio, M. Barbero, A. Bay, U. Bitenc, I. Bizjak, S. Blyth, A. Bondar, A. Bozek, M. Bračko, J. Brodzicka, T. E. Browder, P. ChangY. Chao, A. Chen, K. F. Chen, W. T. Chen, B. G. Cheon, R. Chistov, S. K. Choi, Y. Choi, Y. K. Choi, A. Chuvikov, S. Cole, J. Dalseno, M. Dash, L. Y. Dong, A. Drutskoy, S. Eidelman, Y. Enari, F. Fang, S. Fratina, N. Gabyshev, A. Garmash, T. Gershon, G. Gokhroo, B. Golob, A. Gorišek, J. Haba, K. Hara, T. Hara, N. C. Hastings, H. Hayashii, M. Hazumi, L. Hinz, T. Hokuue, Y. Hoshi, S. Hou, W. S. Hou, Y. B. Hsiung, T. Iijima, A. Imoto, K. Inami, A. Ishikawa, H. Ishino, R. Itoh, M. Iwasaki, Y. Iwasaki, H. Kakuno, J. H. Kang, J. S. Kang, P. Kapusta, N. Katayama, H. Kawai, T. Kawasaki, H. R. Khan, A. Kibayashi, H. Kichimi, S. M. Kim, K. Kinoshita, S. Korpar, P. Križan, P. Krokovny, S. Kumar, C. C. Kuo, A. Kusaka, A. Kuzmin, Y. J. Kwon, G. Leder, S. E. Lee, T. Lesiak, J. Li, S. W. Lin, J. MacNaughton, G. Majumder, F. Mandl, D. Marlow, A. Matyja, Y. Mikami, W. Mitaroff, K. Miyabayashi, H. Miyake, H. Miyata, R. Mizuk, D. Mohapatra, A. Murakami, T. Nagamine, Y. Nagasaka, I. Nakamura, E. Nakano, M. Nakao, H. Nakazawa, Z. Natkaniec, S. Nishida, O. Nitoh, S. Noguchi, T. Nozaki, S. Ogawa, T. Ohshima, T. Okabe, S. Okuno, S. L. Olsen, Y. Onuki, W. Ostrowicz, H. Ozaki, P. Pakhlov, H. Palka, H. Park, N. Parslow, L. S. Peak, R. Pestotnik, L. E. Piilonen, F. J. Ronga, M. Rozanska, H. Sagawa, Y. Sakai, N. Sato, T. Schietinger, O. Schneider, P. Schönmeier, J. Schumann, A. J. Schwartz, K. Senyo, 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. Y. Suzuki, O. Tajima, F. Takasaki, K. Tamai, N. Tamura, M. Tanaka, Y. Teramoto, X. C. Tian, K. Trabelsi, T. Tsuboyama, T. Tsukamoto, S. Uehara, T. Uglov, K. Ueno, Y. Unno, S. Uno, P. Urquijo, Y. Ushiroda, G. Varner, K. E. Varvell, S. Villa, C. C. Wang, C. H. Wang, M. Z. Wang, Y. Watanabe, Q. L. Xie, B. D. Yabsley, A. Yamaguchi, Y. Yamashita, M. Yamauchi, H. Yang, J. Zhang, L. M. Zhang, Z. P. Zhang, V. Zhilich, D. Žontar, D. Zürcher

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Abstract

We present a new measurement of the time-dependent CP-violating parameters in B0→π+π- decays with 275×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Υ(4S) resonance. We find 666±43 B0→π+π- events and measure the CP-violating parameters: Sππ=-0.67±0.16(stat)±0. 06(syst) and Aππ=+0.56±0.12(stat)±0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any Sππ value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle 2 of 0°<2<19° and 71°<2<180°.

Original languageEnglish
Article number101801
JournalPhysical Review Letters
Volume95
Issue number10
DOIs
Publication statusPublished - Sep 2 2005
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Abe, K., Adachi, I., Aihara, H., Arinstein, K., Asano, Y., Aushev, T., Bakich, A. M., Ban, Y., Barberio, E., Barbero, M., Bay, A., Bitenc, U., Bizjak, I., Blyth, S., Bondar, A., Bozek, A., Bračko, M., Brodzicka, J., Browder, T. E., ... Zürcher, D. (2005). Improved evidence for direct CP violation in B0→π+π- decays and model-independent constraints on 2. Physical Review Letters, 95(10), [101801]. https://doi.org/10.1103/PhysRevLett.95.101801