Evidence for direct CP violation in B0-->K+pi- decays

• Published in: Physical review letters 2004-11, Vol.93 (19), p.191802-191802
• Main Authors: Chao, Y, Chang, P, Abe, K, Abe, N, Adachi, I, Aihara, H, Akai, K, Akatsu, M, Akemoto, M, Asano, Y, Aso, T, Aulchenko, V, Aushev, T, Aziz, T, Bahinipati, S, Bakich, A M, Ban, Y, Barbero, M, Bay, A, Bedny, I, Bitenc, U, Bizjak, I, Blyth, S, Bondar, A, Bozek, A, Bracko, M, Brodzicka, J, Browder, T E, Chang, M-C, Chen, A, Chen, K-F, Chen, W T, Cheon, B G, Chistov, R, Choi, S-K, Choi, Y, Choi, Y K, Chuvikov, A, Cole, S, Danilov, M, Dash, M, Dong, L Y, Dowd, R, Dragic, J, Drutskoy, A, Eidelman, S, Eiges, V, Enari, Y, Epifanov, D, Everton, C W, Fang, F, Flanagan, J, Fratina, S, Fujii, H, Funakoshi, Y, Furukawa, K, Gabyshev, N, Garmash, A, Gershon, T, Go, A, Gokhroo, G, Golob, B, Grosse Perdekamp, M, Guler, H, Guo, R, Haba, J, Hagner, C, Handa, F, Hara, K, Hara, T, Hastings, N C, Hasuko, K, Hayasaka, K, Hayashii, H, Hazumi, M, Heenan, E M, Higuchi, I, Higuchi, T, Hinz, L, Hojo, T, Hokuue, T, Hoshi, Y, Hoshina, K, Hou, S, Hou, W-S, Hsiung, Y B, Huang, H-C, Igaki, T, Igarashi, Y, Iijima, T, Ikeda, H, Imoto, A, Inami, K, Ishikawa, A, Ishino, H, Itoh, K, Itoh, R, Iwamoto, M, Iwasaki, M
• Format: Article
• Language: English
• ISSN: 0031-9007

We report evidence for direct CP violation in the decay B0-->K+pi(-) with 253 fb(-1) of data collected with the Belle detector at the KEKB e(+)e(-) collider. Using 275x10(6) BB pairs we observe a B-->K+/-pi(-/+) signal with 2140+/-53 events. The measured CP violating asymmetry is A(CP)(K+pi(-))=-0.101+/-0.025(stat)+/-0.005(syst), corresponding to a significance of 3.9sigma including systematics. We also search for CP violation in the decays B+-->K+pi(0) and B+-->pi(+)pi(0). The measured CP violating asymmetries are A(CP)(K+pi(0))=0.04+/-0.05(stat)+/-0.02(syst) and A(CP)(pi(+)pi(0))=-0.02+/-0.10(stat)+/-0.01(syst), corresponding to the intervals -0.05