Observation of large CP violation and evidence for direct CP violation in B0-->pi(+)pi(-) decays

K Abe; K Abe; N Abe; T Abe; I Adachi; H Aihara; K Akai; M Akatsu; M Akemoto; Y Asano; T Aso; V Aulchenko; T Aushev; A M Bakich; Y Ban; S Banerjee; A Bay; I Bedny; I Bizjak; A Bondar; A Bozek; M Bracko; T E Browder; Y Chao; K F Chen; B G Cheon; R Chistov; S K Choi; Y Choi; A Chuvikov; S Cole; M Danilov; J Dragic; A Drutskoy; S Eidelman; V Eiges; Y Enari; D Epifanov; J Flanagan; K Furukawa; N Gabyshev; A Garmash; T Gershon; B Golob; J Haba; K Hara; N C Hastings; H Hayashii; M Hazumi; L Hinz; T Hokuue; Y Hoshi; W S Hou; Y B Hsiung; H C Huang; T Iijima; H Ikeda; K Inami; A Ishikawa; H Ishino; R Itoh; H Iwasaki; M Iwasaki; Y Iwasaki; H Kakuno; T Kamitani; J H Kang; J S Kang; P Kapusta; S U Kataoka; N Katayama; H Kawai; T Kawasaki; A Kibayashi; H Kichimi; E Kikutani; H J Kim; J H Kim; S K Kim; K Kinoshita; P Koppenburg; S Korpar; P Krizan; P Krokovny; S Kumar; A Kuzmin; Y J Kwon; J S Lange; G Leder; S H Lee; Y J Lee; T Lesiak; J Li; A Limosani; S W Lin; D Liventsev; J MacNaughton; F Mandl; D Marlow; H Matsumoto; T Matsumoto; A Matyja; S Michizono; T Mimashi; W Mitaroff; K Miyabayashi; H Miyake; H Miyata; D Mohapatra; G R Moloney; A Murakami; T Nagamine; Y Nagasaka; T Nakadaira; T T Nakamura; E Nakano; M Nakao; H Nakazawa; Z Natkaniec; K Neichi; S Nishida; O Nitoh; S Noguchi; T Nozaki; S Ogawa; Y Ogawa; K Ohmi; T Ohshima; N Ohuchi; K Oide; T Okabe; S Okuno; S L Olsen; W Ostrowicz; H Ozaki; P Pakhlov; H Palka; C W Park; H Park; N Parslow; L E Piilonen; N Root; M Rozanska; H Sagawa; Y Sakai; O Schneider; J Schümann; C Schwanda; A J Schwartz; S Semenov; K Senyo; H Shibuya; T Shidara; B Shwartz; V Sidorov; J B Singh; N Soni; R Stamen; S Stanic; M Staric; R Sugahara; K Sumisawa; T Sumiyoshi; K Suzuki; S Suzuki; O Tajima; F Takasaki; K Tamai; N Tamura; M Tanaka; M Tawada; Y Teramoto; T Tomura; T Tsuboyama; T Tsukamoto; S Uehara; T Uglov; K Ueno; Y Unno; S Uno; G Varner; K E Varvell; C C Wang; C H Wang; M Z Wang; Y Watanabe; B D Yabsley; Y Yamada; A Yamaguchi; Y Yamashita; M Yamauchi; H Yanai; Heyoung Yang; J Ying; M Yokoyama; M Yoshida; Y Yusa; C C Zhang; Z P Zhang; T Ziegler; D Zontar; D Zürcher

doi:10.1103/PhysRevLett.93.021601

Observation of large CP violation and evidence for direct CP violation in B0-->pi(+)pi(-) decays

Phys Rev Lett. 2004 Jul 9;93(2):021601. doi: 10.1103/PhysRevLett.93.021601. Epub 2004 Jul 6.

Authors

K Abe¹, K Abe, N Abe, T Abe, I Adachi, H Aihara, K Akai, M Akatsu, M Akemoto, Y Asano, T Aso, V Aulchenko, T Aushev, A M Bakich, Y Ban, S Banerjee, A Bay, I Bedny, I Bizjak, A Bondar, A Bozek, M Bracko, T E Browder, Y Chao, K F Chen, B G Cheon, R Chistov, S K Choi, Y Choi, A Chuvikov, S Cole, M Danilov, J Dragic, A Drutskoy, S Eidelman, V Eiges, Y Enari, D Epifanov, J Flanagan, K Furukawa, N Gabyshev, A Garmash, T Gershon, B Golob, J Haba, K Hara, N C Hastings, H Hayashii, M Hazumi, L Hinz, T Hokuue, Y Hoshi, W S Hou, Y B Hsiung, H C Huang, T Iijima, H Ikeda, K Inami, A Ishikawa, H Ishino, R Itoh, H Iwasaki, M Iwasaki, Y Iwasaki, H Kakuno, T Kamitani, J H Kang, J S Kang, P Kapusta, S U Kataoka, N Katayama, H Kawai, T Kawasaki, A Kibayashi, H Kichimi, E Kikutani, H J Kim, J H Kim, S K Kim, K Kinoshita, P Koppenburg, S Korpar, P Krizan, P Krokovny, S Kumar, A Kuzmin, Y J Kwon, J S Lange, G Leder, S H Lee, Y J Lee, T Lesiak, J Li, A Limosani, S W Lin, D Liventsev, J MacNaughton, F Mandl, D Marlow, H Matsumoto, T Matsumoto, A Matyja, S Michizono, T Mimashi, W Mitaroff, K Miyabayashi, H Miyake, H Miyata, D Mohapatra, G R Moloney, A Murakami, T Nagamine, Y Nagasaka, T Nakadaira, T T Nakamura, E Nakano, M Nakao, H Nakazawa, Z Natkaniec, K Neichi, S Nishida, O Nitoh, S Noguchi, T Nozaki, S Ogawa, Y Ogawa, K Ohmi, T Ohshima, N Ohuchi, K Oide, T Okabe, S Okuno, S L Olsen, W Ostrowicz, H Ozaki, P Pakhlov, H Palka, C W Park, H Park, N Parslow, L E Piilonen, N Root, M Rozanska, H Sagawa, Y Sakai, O Schneider, J Schümann, C Schwanda, A J Schwartz, S Semenov, K Senyo, H Shibuya, T Shidara, B Shwartz, V Sidorov, J B Singh, N Soni, R Stamen, S Stanic, M Staric, R Sugahara, K Sumisawa, T Sumiyoshi, K Suzuki, S Suzuki, O Tajima, F Takasaki, K Tamai, N Tamura, M Tanaka, M Tawada, Y Teramoto, T Tomura, T Tsuboyama, T Tsukamoto, S Uehara, T Uglov, K Ueno, Y Unno, S Uno, G Varner, K E Varvell, C C Wang, C H Wang, M Z Wang, Y Watanabe, B D Yabsley, Y Yamada, A Yamaguchi, Y Yamashita, M Yamauchi, H Yanai, Heyoung Yang, J Ying, M Yokoyama, M Yoshida, Y Yusa, C C Zhang, Z P Zhang, T Ziegler, D Zontar, D Zürcher

Affiliation

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

PMID: 15323897
DOI: 10.1103/PhysRevLett.93.021601

Abstract

We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value.