Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2

Hirokazu Ishino, K. Abe, K. Abe, I. Adachi, H. Aihara, D. Anipko, K. Arinstein, T. Aushev, A. M. Bakich, E. Barberio, M. Barbero, I. Bedny, U. Bitenc, I. Bizjak, S. Blyth, A. Bozek, M. Bračko, T. E. Browder, M. C. Chang, P. Chang & 142 others Y. Chao, A. Chen, K. F. Chen, W. T. Chen, B. G. Cheon, R. Chistov, Y. Choi, Y. K. Choi, S. Cole, J. Dalseno, M. Dash, A. Drutskoy, S. Eidelman, S. Fratina, T. Gershon, A. Go, G. Gokhroo, B. Golob, A. Gorišek, H. Ha, J. Haba, K. Hara, K. Hayasaka, M. Hazumi, D. Heffernan, T. Hokuue, Y. Hoshi, S. Hou, Y. B. Hsiung, T. Iijima, A. Imoto, K. Inami, A. Ishikawa, Y. Iwasaki, J. H. Kang, P. Kapusta, S. U. Kataoka, N. Katayama, H. Kawai, T. Kawasaki, H. R. Khan, A. Kibayashi, H. Kichimi, K. Kinoshita, S. Korpar, P. Križan, P. Krokovny, R. Kulasiri, R. Kumar, C. C. Kuo, A. Kusaka, A. Kuzmin, Y. J. Kwon, M. J. Lee, S. E. Lee, T. Lesiak, A. Limosani, S. W. Lin, J. MacNaughton, F. Mandl, D. Marlow, T. Matsumoto, A. Matyja, S. McOnie, W. Mitaroff, K. Miyabayashi, H. Miyake, H. Miyata, Y. Miyazaki, R. Mizuk, D. Mohapatra, Y. Nagasaka, E. Nakano, M. Nakao, S. Nishida, O. Nitoh, T. Nozaki, S. Ogawa, T. Ohshima, S. L. Olsen, Y. Onuki, H. Ozaki, P. Pakhlov, G. Pakhlova, H. Park, L. S. Peak, R. Pestotnik, L. E. Piilonen, H. Sahoo, Y. Sakai, N. Satoyama, T. Schietinger, O. Schneider, J. Schümann, C. Schwanda, A. J. Schwartz, R. Seidl, K. Senyo, M. E. Sevior, H. Shibuya, B. Shwartz, A. Somov, N. Soni, S. Stanič, M. Starič, H. Stoeck, K. Sumisawa, T. Sumiyoshi, S. Y. Suzuki, O. Tajima, F. Takasaki, K. Tamai, N. Tamura, M. Tanaka, Y. Teramoto, X. C. Tian, K. Trabelsi, T. Tsukamoto, S. Uehara, K. Ueno, Y. Unno, S. Uno, P. Urquijo, Y. Ushiroda, Y. Usov, G. Varner, K. E. Varvell, S. Villa, C. H. Wang, M. Z. Wang, Y. Watanabe, E. Won, C. H. Wu, Q. L. Xie, B. D. Yabsley, A. Yamaguchi, Y. Yamashita, M. Yamauchi, L. M. Zhang, Z. P. Zhang, V. Zhilich, A. Zupanc

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

We report a new measurement of the time-dependent CP-violating parameters in B0→π+π- decays with 535×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Υ(4S) resonance. We find 1464±65 B0→π+π- events and measure the CP-violating parameters Sππ=-0.61±0.10(stat)±0. 04(syst) and Aππ=+0.55±0.08(stat)±0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any Sππ value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle 2=(97±11)° for the solution consistent with the standard model and exclude the range 11°<2

Original languageEnglish
Article number211801
JournalPhysical Review Letters
Volume98
Issue number21
DOIs
Publication statusPublished - May 21 2007
Externally publishedYes

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CP violation
quarks
decay
standard deviation
detectors
matrices
energy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2. / Ishino, Hirokazu; Abe, K.; Abe, K.; Adachi, I.; Aihara, H.; Anipko, D.; Arinstein, K.; Aushev, T.; Bakich, A. M.; Barberio, E.; Barbero, M.; Bedny, I.; Bitenc, U.; Bizjak, I.; Blyth, S.; Bozek, A.; Bračko, M.; Browder, T. E.; Chang, M. C.; Chang, P.; Chao, Y.; Chen, A.; Chen, K. F.; Chen, W. T.; Cheon, B. G.; Chistov, R.; Choi, Y.; Choi, Y. K.; Cole, S.; Dalseno, J.; Dash, M.; Drutskoy, A.; Eidelman, S.; Fratina, S.; Gershon, T.; Go, A.; Gokhroo, G.; Golob, B.; Gorišek, A.; Ha, H.; Haba, J.; Hara, K.; Hayasaka, K.; Hazumi, M.; Heffernan, D.; Hokuue, T.; Hoshi, Y.; Hou, S.; Hsiung, Y. B.; Iijima, T.; Imoto, A.; Inami, K.; Ishikawa, A.; Iwasaki, Y.; Kang, J. H.; Kapusta, P.; Kataoka, S. U.; Katayama, N.; Kawai, H.; Kawasaki, T.; Khan, H. R.; Kibayashi, A.; Kichimi, H.; Kinoshita, K.; Korpar, S.; Križan, P.; Krokovny, P.; Kulasiri, R.; Kumar, R.; Kuo, C. C.; Kusaka, A.; Kuzmin, A.; Kwon, Y. J.; Lee, M. J.; Lee, S. E.; Lesiak, T.; Limosani, A.; Lin, S. W.; MacNaughton, J.; Mandl, F.; Marlow, D.; Matsumoto, T.; Matyja, A.; McOnie, S.; Mitaroff, W.; Miyabayashi, K.; Miyake, H.; Miyata, H.; Miyazaki, Y.; Mizuk, R.; Mohapatra, D.; Nagasaka, Y.; Nakano, E.; Nakao, M.; Nishida, S.; Nitoh, O.; Nozaki, T.; Ogawa, S.; Ohshima, T.; Olsen, S. L.; Onuki, Y.; Ozaki, H.; Pakhlov, P.; Pakhlova, G.; Park, H.; Peak, L. S.; Pestotnik, R.; Piilonen, L. E.; Sahoo, H.; Sakai, Y.; Satoyama, N.; Schietinger, T.; Schneider, O.; Schümann, J.; Schwanda, C.; Schwartz, A. J.; Seidl, R.; Senyo, K.; Sevior, M. E.; Shibuya, H.; Shwartz, B.; Somov, A.; Soni, N.; Stanič, S.; Starič, M.; Stoeck, H.; Sumisawa, K.; Sumiyoshi, T.; Suzuki, S. Y.; Tajima, O.; Takasaki, F.; Tamai, K.; Tamura, N.; Tanaka, M.; Teramoto, Y.; Tian, X. C.; Trabelsi, K.; Tsukamoto, T.; Uehara, S.; Ueno, K.; Unno, Y.; Uno, S.; Urquijo, P.; Ushiroda, Y.; Usov, Y.; Varner, G.; Varvell, K. E.; Villa, S.; Wang, C. H.; Wang, M. Z.; Watanabe, Y.; Won, E.; Wu, C. H.; Xie, Q. L.; Yabsley, B. D.; Yamaguchi, A.; Yamashita, Y.; Yamauchi, M.; Zhang, L. M.; Zhang, Z. P.; Zhilich, V.; Zupanc, A.

In: Physical Review Letters, Vol. 98, No. 21, 211801, 21.05.2007.

Research output: Contribution to journalArticle

Ishino, H, Abe, K, Abe, K, Adachi, I, Aihara, H, Anipko, D, Arinstein, K, Aushev, T, Bakich, AM, Barberio, E, Barbero, M, Bedny, I, Bitenc, U, Bizjak, I, Blyth, S, Bozek, A, Bračko, M, Browder, TE, Chang, MC, Chang, P, Chao, Y, Chen, A, Chen, KF, Chen, WT, Cheon, BG, Chistov, R, Choi, Y, Choi, YK, Cole, S, Dalseno, J, Dash, M, Drutskoy, A, Eidelman, S, Fratina, S, Gershon, T, Go, A, Gokhroo, G, Golob, B, Gorišek, A, Ha, H, Haba, J, Hara, K, Hayasaka, K, Hazumi, M, Heffernan, D, Hokuue, T, Hoshi, Y, Hou, S, Hsiung, YB, Iijima, T, Imoto, A, Inami, K, Ishikawa, A, Iwasaki, Y, Kang, JH, Kapusta, P, Kataoka, SU, Katayama, N, Kawai, H, Kawasaki, T, Khan, HR, Kibayashi, A, Kichimi, H, Kinoshita, K, Korpar, S, Križan, P, Krokovny, P, Kulasiri, R, Kumar, R, Kuo, CC, Kusaka, A, Kuzmin, A, Kwon, YJ, Lee, MJ, Lee, SE, Lesiak, T, Limosani, A, Lin, SW, MacNaughton, J, Mandl, F, Marlow, D, Matsumoto, T, Matyja, A, McOnie, S, Mitaroff, W, Miyabayashi, K, Miyake, H, Miyata, H, Miyazaki, Y, Mizuk, R, Mohapatra, D, Nagasaka, Y, Nakano, E, Nakao, M, Nishida, S, Nitoh, O, Nozaki, T, Ogawa, S, Ohshima, T, Olsen, SL, Onuki, Y, Ozaki, H, Pakhlov, P, Pakhlova, G, Park, H, Peak, LS, Pestotnik, R, Piilonen, LE, Sahoo, H, Sakai, Y, Satoyama, N, Schietinger, T, Schneider, O, Schümann, J, Schwanda, C, Schwartz, AJ, Seidl, R, Senyo, K, Sevior, ME, Shibuya, H, Shwartz, B, Somov, A, Soni, N, Stanič, S, Starič, M, Stoeck, H, Sumisawa, K, Sumiyoshi, T, Suzuki, SY, Tajima, O, Takasaki, F, Tamai, K, Tamura, N, Tanaka, M, Teramoto, Y, Tian, XC, Trabelsi, K, Tsukamoto, T, Uehara, S, Ueno, K, Unno, Y, Uno, S, Urquijo, P, Ushiroda, Y, Usov, Y, Varner, G, Varvell, KE, Villa, S, Wang, CH, Wang, MZ, Watanabe, Y, Won, E, Wu, CH, Xie, QL, Yabsley, BD, Yamaguchi, A, Yamashita, Y, Yamauchi, M, Zhang, LM, Zhang, ZP, Zhilich, V & Zupanc, A 2007, 'Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2', Physical Review Letters, vol. 98, no. 21, 211801. https://doi.org/10.1103/PhysRevLett.98.211801
Ishino, Hirokazu ; Abe, K. ; Abe, K. ; Adachi, I. ; Aihara, H. ; Anipko, D. ; Arinstein, K. ; Aushev, T. ; Bakich, A. M. ; Barberio, E. ; Barbero, M. ; Bedny, I. ; Bitenc, U. ; Bizjak, I. ; Blyth, S. ; Bozek, A. ; Bračko, M. ; Browder, T. E. ; Chang, M. C. ; Chang, P. ; Chao, Y. ; Chen, A. ; Chen, K. F. ; Chen, W. T. ; Cheon, B. G. ; Chistov, R. ; Choi, Y. ; Choi, Y. K. ; Cole, S. ; Dalseno, J. ; Dash, M. ; Drutskoy, A. ; Eidelman, S. ; Fratina, S. ; Gershon, T. ; Go, A. ; Gokhroo, G. ; Golob, B. ; Gorišek, A. ; Ha, H. ; Haba, J. ; Hara, K. ; Hayasaka, K. ; Hazumi, M. ; Heffernan, D. ; Hokuue, T. ; Hoshi, Y. ; Hou, S. ; Hsiung, Y. B. ; Iijima, T. ; Imoto, A. ; Inami, K. ; Ishikawa, A. ; Iwasaki, Y. ; Kang, J. H. ; Kapusta, P. ; Kataoka, S. U. ; Katayama, N. ; Kawai, H. ; Kawasaki, T. ; Khan, H. R. ; Kibayashi, A. ; Kichimi, H. ; Kinoshita, K. ; Korpar, S. ; Križan, P. ; Krokovny, P. ; Kulasiri, R. ; Kumar, R. ; Kuo, C. C. ; Kusaka, A. ; Kuzmin, A. ; Kwon, Y. J. ; Lee, M. J. ; Lee, S. E. ; Lesiak, T. ; Limosani, A. ; Lin, S. W. ; MacNaughton, J. ; Mandl, F. ; Marlow, D. ; Matsumoto, T. ; Matyja, A. ; McOnie, S. ; Mitaroff, W. ; Miyabayashi, K. ; Miyake, H. ; Miyata, H. ; Miyazaki, Y. ; Mizuk, R. ; Mohapatra, D. ; Nagasaka, Y. ; Nakano, E. ; Nakao, M. ; Nishida, S. ; Nitoh, O. ; Nozaki, T. ; Ogawa, S. ; Ohshima, T. ; Olsen, S. L. ; Onuki, Y. ; Ozaki, H. ; Pakhlov, P. ; Pakhlova, G. ; Park, H. ; Peak, L. S. ; Pestotnik, R. ; Piilonen, L. E. ; Sahoo, H. ; Sakai, Y. ; Satoyama, N. ; Schietinger, T. ; Schneider, O. ; Schümann, J. ; Schwanda, C. ; Schwartz, A. J. ; Seidl, R. ; Senyo, K. ; Sevior, M. E. ; Shibuya, H. ; Shwartz, B. ; Somov, A. ; Soni, N. ; Stanič, S. ; Starič, M. ; Stoeck, H. ; Sumisawa, K. ; Sumiyoshi, T. ; Suzuki, S. Y. ; Tajima, O. ; Takasaki, F. ; Tamai, K. ; Tamura, N. ; Tanaka, M. ; Teramoto, Y. ; Tian, X. C. ; Trabelsi, K. ; Tsukamoto, T. ; Uehara, S. ; Ueno, K. ; Unno, Y. ; Uno, S. ; Urquijo, P. ; Ushiroda, Y. ; Usov, Y. ; Varner, G. ; Varvell, K. E. ; Villa, S. ; Wang, C. H. ; Wang, M. Z. ; Watanabe, Y. ; Won, E. ; Wu, C. H. ; Xie, Q. L. ; Yabsley, B. D. ; Yamaguchi, A. ; Yamashita, Y. ; Yamauchi, M. ; Zhang, L. M. ; Zhang, Z. P. ; Zhilich, V. ; Zupanc, A. / Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2. In: Physical Review Letters. 2007 ; Vol. 98, No. 21.
@article{703f43b0f9264fce8e40e7e09470d911,
title = "Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2",
abstract = "We report a new measurement of the time-dependent CP-violating parameters in B0→π+π- decays with 535×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Υ(4S) resonance. We find 1464±65 B0→π+π- events and measure the CP-violating parameters Sππ=-0.61±0.10(stat)±0. 04(syst) and Aππ=+0.55±0.08(stat)±0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any Sππ value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle 2=(97±11)° for the solution consistent with the standard model and exclude the range 11°<2",
author = "Hirokazu Ishino and K. Abe and K. Abe and I. Adachi and H. Aihara and D. Anipko and K. Arinstein and T. Aushev and Bakich, {A. M.} and E. Barberio and M. Barbero and I. Bedny and U. Bitenc and I. Bizjak and S. Blyth and A. Bozek and M. Bračko and Browder, {T. E.} and Chang, {M. C.} and P. Chang and Y. Chao and A. Chen and Chen, {K. F.} and Chen, {W. T.} and Cheon, {B. G.} and R. Chistov and Y. Choi and Choi, {Y. K.} and S. Cole and J. Dalseno and M. Dash and A. Drutskoy and S. Eidelman and S. Fratina and T. Gershon and A. Go and G. Gokhroo and B. Golob and A. Gorišek and H. Ha and J. Haba and K. Hara and K. Hayasaka and M. Hazumi and D. Heffernan and T. Hokuue and Y. Hoshi and S. Hou and Hsiung, {Y. B.} and T. Iijima and A. Imoto and K. Inami and A. Ishikawa and Y. Iwasaki and Kang, {J. H.} and P. Kapusta and Kataoka, {S. U.} and N. Katayama and H. Kawai and T. Kawasaki and Khan, {H. R.} and A. Kibayashi and H. Kichimi and K. Kinoshita and S. Korpar and P. Križan and P. Krokovny and R. Kulasiri and R. Kumar and Kuo, {C. C.} and A. Kusaka and A. Kuzmin and Kwon, {Y. J.} and Lee, {M. J.} and Lee, {S. E.} and T. Lesiak and A. Limosani and Lin, {S. W.} and J. MacNaughton and F. Mandl and D. Marlow and T. Matsumoto and A. Matyja and S. McOnie and W. Mitaroff and K. Miyabayashi and H. Miyake and H. Miyata and Y. Miyazaki and R. Mizuk and D. Mohapatra and Y. Nagasaka and E. Nakano and M. Nakao and S. Nishida and O. Nitoh and T. Nozaki and S. Ogawa and T. Ohshima and Olsen, {S. L.} and Y. Onuki and H. Ozaki and P. Pakhlov and G. Pakhlova and H. Park and Peak, {L. S.} and R. Pestotnik and Piilonen, {L. E.} and H. Sahoo and Y. Sakai and N. Satoyama and T. Schietinger and O. Schneider and J. Sch{\"u}mann and C. Schwanda and Schwartz, {A. J.} and R. Seidl and K. Senyo and Sevior, {M. E.} and H. Shibuya and B. Shwartz and A. Somov and N. Soni and S. Stanič and M. Starič and H. Stoeck and K. Sumisawa and T. Sumiyoshi and Suzuki, {S. Y.} and O. Tajima and F. Takasaki and K. Tamai and N. Tamura and M. Tanaka and Y. Teramoto and Tian, {X. C.} and K. Trabelsi and T. Tsukamoto and S. Uehara and K. Ueno and Y. Unno and S. Uno and P. Urquijo and Y. Ushiroda and Y. Usov and G. Varner and Varvell, {K. E.} and S. Villa and Wang, {C. H.} and Wang, {M. Z.} and Y. Watanabe and E. Won and Wu, {C. H.} and Xie, {Q. L.} and Yabsley, {B. D.} and A. Yamaguchi and Y. Yamashita and M. Yamauchi and Zhang, {L. M.} and Zhang, {Z. P.} and V. Zhilich and A. Zupanc",
year = "2007",
month = "5",
day = "21",
doi = "10.1103/PhysRevLett.98.211801",
language = "English",
volume = "98",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "21",

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TY - JOUR

T1 - Observation of direct CP violation in B0→π+π- decays and model-independent constraints on the quark-mixing angle 2

AU - Ishino, Hirokazu

AU - Abe, K.

AU - Abe, K.

AU - Adachi, I.

AU - Aihara, H.

AU - Anipko, D.

AU - Arinstein, K.

AU - Aushev, T.

AU - Bakich, A. M.

AU - Barberio, E.

AU - Barbero, M.

AU - Bedny, I.

AU - Bitenc, U.

AU - Bizjak, I.

AU - Blyth, S.

AU - Bozek, A.

AU - Bračko, M.

AU - Browder, T. E.

AU - Chang, M. C.

AU - Chang, P.

AU - Chao, Y.

AU - Chen, A.

AU - Chen, K. F.

AU - Chen, W. T.

AU - Cheon, B. G.

AU - Chistov, R.

AU - Choi, Y.

AU - Choi, Y. K.

AU - Cole, S.

AU - Dalseno, J.

AU - Dash, M.

AU - Drutskoy, A.

AU - Eidelman, S.

AU - Fratina, S.

AU - Gershon, T.

AU - Go, A.

AU - Gokhroo, G.

AU - Golob, B.

AU - Gorišek, A.

AU - Ha, H.

AU - Haba, J.

AU - Hara, K.

AU - Hayasaka, K.

AU - Hazumi, M.

AU - Heffernan, D.

AU - Hokuue, T.

AU - Hoshi, Y.

AU - Hou, S.

AU - Hsiung, Y. B.

AU - Iijima, T.

AU - Imoto, A.

AU - Inami, K.

AU - Ishikawa, A.

AU - Iwasaki, Y.

AU - Kang, J. H.

AU - Kapusta, P.

AU - Kataoka, S. U.

AU - Katayama, N.

AU - Kawai, H.

AU - Kawasaki, T.

AU - Khan, H. R.

AU - Kibayashi, A.

AU - Kichimi, H.

AU - Kinoshita, K.

AU - Korpar, S.

AU - Križan, P.

AU - Krokovny, P.

AU - Kulasiri, R.

AU - Kumar, R.

AU - Kuo, C. C.

AU - Kusaka, A.

AU - Kuzmin, A.

AU - Kwon, Y. J.

AU - Lee, M. J.

AU - Lee, S. E.

AU - Lesiak, T.

AU - Limosani, A.

AU - Lin, S. W.

AU - MacNaughton, J.

AU - Mandl, F.

AU - Marlow, D.

AU - Matsumoto, T.

AU - Matyja, A.

AU - McOnie, S.

AU - Mitaroff, W.

AU - Miyabayashi, K.

AU - Miyake, H.

AU - Miyata, H.

AU - Miyazaki, Y.

AU - Mizuk, R.

AU - Mohapatra, D.

AU - Nagasaka, Y.

AU - Nakano, E.

AU - Nakao, M.

AU - Nishida, S.

AU - Nitoh, O.

AU - Nozaki, T.

AU - Ogawa, S.

AU - Ohshima, T.

AU - Olsen, S. L.

AU - Onuki, Y.

AU - Ozaki, H.

AU - Pakhlov, P.

AU - Pakhlova, G.

AU - Park, H.

AU - Peak, L. S.

AU - Pestotnik, R.

AU - Piilonen, L. E.

AU - Sahoo, H.

AU - Sakai, Y.

AU - Satoyama, N.

AU - Schietinger, T.

AU - Schneider, O.

AU - Schümann, J.

AU - Schwanda, C.

AU - Schwartz, A. J.

AU - Seidl, R.

AU - Senyo, K.

AU - Sevior, M. E.

AU - Shibuya, H.

AU - Shwartz, B.

AU - Somov, A.

AU - Soni, N.

AU - Stanič, S.

AU - Starič, M.

AU - Stoeck, H.

AU - Sumisawa, K.

AU - Sumiyoshi, T.

AU - Suzuki, S. Y.

AU - Tajima, O.

AU - Takasaki, F.

AU - Tamai, K.

AU - Tamura, N.

AU - Tanaka, M.

AU - Teramoto, Y.

AU - Tian, X. C.

AU - Trabelsi, K.

AU - Tsukamoto, T.

AU - Uehara, S.

AU - Ueno, K.

AU - Unno, Y.

AU - Uno, S.

AU - Urquijo, P.

AU - Ushiroda, Y.

AU - Usov, Y.

AU - Varner, G.

AU - Varvell, K. E.

AU - Villa, S.

AU - Wang, C. H.

AU - Wang, M. Z.

AU - Watanabe, Y.

AU - Won, E.

AU - Wu, C. H.

AU - Xie, Q. L.

AU - Yabsley, B. D.

AU - Yamaguchi, A.

AU - Yamashita, Y.

AU - Yamauchi, M.

AU - Zhang, L. M.

AU - Zhang, Z. P.

AU - Zhilich, V.

AU - Zupanc, A.

PY - 2007/5/21

Y1 - 2007/5/21

N2 - We report a new measurement of the time-dependent CP-violating parameters in B0→π+π- decays with 535×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Υ(4S) resonance. We find 1464±65 B0→π+π- events and measure the CP-violating parameters Sππ=-0.61±0.10(stat)±0. 04(syst) and Aππ=+0.55±0.08(stat)±0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any Sππ value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle 2=(97±11)° for the solution consistent with the standard model and exclude the range 11°<2

AB - We report a new measurement of the time-dependent CP-violating parameters in B0→π+π- decays with 535×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Υ(4S) resonance. We find 1464±65 B0→π+π- events and measure the CP-violating parameters Sππ=-0.61±0.10(stat)±0. 04(syst) and Aππ=+0.55±0.08(stat)±0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any Sππ value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle 2=(97±11)° for the solution consistent with the standard model and exclude the range 11°<2

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UR - http://www.scopus.com/inward/citedby.url?scp=34547373860&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.98.211801

DO - 10.1103/PhysRevLett.98.211801

M3 - Article

VL - 98

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 21

M1 - 211801

ER -