Improved evidence for direct CP violation in B0-->pi+pi- decays and model-independent constraints on phi2

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 Bracko; J Brodzicka; T E Browder; P Chang; Y 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 Gorisek; 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 Krizan; 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 Schümann; A J Schwartz; K Senyo; M E Sevior; H Shibuya; B Shwartz; V Sidorov; J B Singh; A Somov; N Soni; R Stamen; S Stanic; M Staric; 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; Heyoung Yang; J Zhang; L M Zhang; Z P Zhang; V Zhilich; D Zontar; D Zürcher; Belle Collaboration

doi:10.1103/PhysRevLett.95.101801

Improved evidence for direct CP violation in B0-->pi+pi- decays and model-independent constraints on phi2

Phys Rev Lett. 2005 Sep 2;95(10):101801. doi: 10.1103/PhysRevLett.95.101801. Epub 2005 Aug 31.

Authors

K Abe¹, 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 Bracko, J Brodzicka, T E Browder, P Chang, Y 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 Gorisek, 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 Krizan, 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 Schümann, A J Schwartz, K Senyo, M E Sevior, H Shibuya, B Shwartz, V Sidorov, J B Singh, A Somov, N Soni, R Stamen, S Stanic, M Staric, 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, Heyoung Yang, J Zhang, L M Zhang, Z P Zhang, V Zhilich, D Zontar, D Zürcher; Belle Collaboration

Affiliation

¹ High Energy Accelerator Research Organization (KEK), Tsukuba.

PMID: 16196917
DOI: 10.1103/PhysRevLett.95.101801

Abstract

We present a new measurement of the time-dependent CP-violating parameters in B(0)--> pi(+)pi(-) decays with 275 x 10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Gamma(4S) resonance. We find 666 +/- 43 B(0) --> pi(+)pi(-) events and measure the CP-violating parameters: S(pipi) = -0.67 +/- 0.16(stat) +/- 0.06(syst) and A(pipi) = +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 S(pipi) value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2) of 0 degree < phiv(2) < 19 degrees and 71 degrees < phi(2) < 180 degrees.