Vidence for CP-violating asymmetries in B 0→π +π - decays and constraints on the CKM angle φ 2

K. Abe; K. Abe; N. Abe; T. Abe; I. Adachi; H. Aihara; K. Akai; M. Akatsu; M. Akemoto; Y. Asano; T. Aushev; A. M. Bakich; Y. Ban; E. Banas; A. Bay; I. Bedny; P. K. Behera; I. Bizjak; A. Bondar; A. Bozek; M. Bračko; J. Brodzicka; T. E. Browder; B. C.K. Casey; P. Chang; K. F. Chen; B. G. Cheon; R. Chistov; S. K. Choi; Y. Choi; Y. K. Choi; M. Danilov; J. Dragic; A. Drutskoy; S. Eidelman; V. Eiges; C. W. Everton; J. Flanagan; C. Fukunaga; K. Furukawa; N. Gabyshev; A. Garmash; T. Gershon; B. Golob; R. Guo; C. Hagner; K. Hara; N. C. Hastings; K. Hasuko; H. Hayashii; M. Hazumi; T. Higuchi; L. Hinz; T. Hojo; T. Hokuue; Y. Hoshi; W. S. Hou; Y. B. Hsiung; H. C. Huang; T. Igaki; Y. Igarashi; T. Iijima; H. Ikeda; K. Inami; A. Ishikawa; H. Ishino; R. Itoh; H. Iwasaki; Y. Iwasaki; H. K. Jang; J. S. Kang; P. Kapusta; S. U. Kataoka; N. Katayama; G. Katano; H. Kawai; N. Kawamura; T. Kawasaki; H. Kichimi; M. Kikuchi; E. Kikutani; D. W. Kim; H. J. Kim; H. O. Kim; H. Kim; J. H. Kim; S. K. Kim; S. Kobayashi; S. Korpar; P. Križan; P. Krokovny; T. Kubo; R. Kulasiri; S. Kumar; A. Kuzmin; Y. J. Kwon; J. S. Lange; G. Leder; S. H. Lee; J. Li; S. W. Lin; J. MacNaughton; F. Mandl; D. Marlow; S. Matsumoto; T. Matsumoto; S. Michizono; T. Mimashi; W. Mitaroff; K. Miyabayashi; H. Miyake; H. Miyata; G. R. Moloney; T. Mori; A. Murakami; Y. Nagasaka; T. Nakadaira; T. T. Nakamura; E. Nakano; M. Nakao; H. Nakayama; J. W. Nam; K. Neichi; S. Nishida; O. Nitoh; S. Noguchi; T. Nozaki; S. Ogawa; Y. Ogawa; K. Ohmi; Y. Ohnishi; T. Ohshima; N. Ohuchi; T. Okabe; S. Okuno; S. L. Olsen; Y. Onuki; W. Ostrowicz; H. Ozaki; H. Palka; C. W. Park; H. Park; K. S. Park; L. S. Peak; J. P. Perroud; M. Peters; L. E. Piilonen; M. Rozanska; K. Rybicki; H. Sagawa; S. Saitoh; Y. Sakai; T. R. Sarangi; M. Satapathy; A. Satpathy; O. Schneider; S. Schrenk; J. Schümann; C. Schwanda; S. Semenov; K. Senyo; M. E. Sevior; H. Shibuya; T. Shidara; B. Shwartz; V. Sidorov; J. B. Singh; S. Stanič; M. Starič; R. Sugahara; A. Sugiyama; K. Sumisawa; T. Sumiyoshi; K. Suzuki; S. Suzuki; T. Takahashi; F. Takasaki; K. Tamai; N. Tamura; J. Tanaka; M. Tanaka; M. Tawada; G. N. Taylor; Y. Teramoto; S. Tokuda; T. Tomura; K. Trabelsi; T. Tsuboyama; T. Tsukamoto; S. Uehara; Y. Unno; S. Uno; N. Uozaki; S. E. Vahsen; G. Varner; K. E. Varvell; C. C. Wang; C. H. Wang; J. G. Wang; M. Z. Wang; Y. Watanabe; E. Won; B. D. Yabsley; Y. Yamada; A. Yamaguchi; H. Yamamoto; Y. Yamashita; Y. Yamashita; M. Yamauchi; M. Yokoyama; M. Yoshida; C. C. Zhang; Z. P. Zhang; V. Zhilich; D. Žontar

doi:10.1103/PhysRevD.68.012001

Vidence for CP-violating asymmetries in B ⁰→π ⁺π ^- decays and constraints on the CKM angle φ ₂

K. Abe, K. Abe, N. Abe, T. Abe, I. Adachi, H. Aihara, K. Akai, M. Akatsu, M. Akemoto, Y. Asano, T. Aushev, A. M. Bakich, Y. Ban, E. Banas, A. Bay, I. Bedny, P. K. Behera, I. Bizjak, A. Bondar, A. BozekM. Bračko, J. Brodzicka, T. E. Browder, B. C.K. Casey, P. Chang, K. F. Chen, B. G. Cheon, R. Chistov, S. K. Choi, Y. Choi, Y. K. Choi, M. Danilov, J. Dragic, A. Drutskoy, S. Eidelman, V. Eiges, C. W. Everton, J. Flanagan, C. Fukunaga, K. Furukawa, N. Gabyshev, A. Garmash, T. Gershon, B. Golob, R. Guo, C. Hagner, K. Hara, N. C. Hastings, K. Hasuko, H. Hayashii, M. Hazumi, T. Higuchi, L. Hinz, T. Hojo, T. Hokuue, Y. Hoshi, W. S. Hou, Y. B. Hsiung, H. C. Huang, T. Igaki, Y. Igarashi, T. Iijima, H. Ikeda, K. Inami, A. Ishikawa, H. Ishino, R. Itoh, H. Iwasaki, Y. Iwasaki, H. K. Jang, J. S. Kang, P. Kapusta, S. U. Kataoka, N. Katayama, G. Katano, H. Kawai, N. Kawamura, T. Kawasaki, H. Kichimi, M. Kikuchi, E. Kikutani, D. W. Kim, H. J. Kim, H. O. Kim, H. Kim, J. H. Kim, S. K. Kim, S. Kobayashi, S. Korpar, P. Križan, P. Krokovny, T. Kubo, R. Kulasiri, S. Kumar, A. Kuzmin, Y. J. Kwon, J. S. Lange, G. Leder, S. H. Lee, J. Li, S. W. Lin, J. MacNaughton, F. Mandl, D. Marlow, S. Matsumoto, T. Matsumoto, S. Michizono, T. Mimashi, W. Mitaroff, K. Miyabayashi, H. Miyake, H. Miyata, G. R. Moloney, T. Mori, A. Murakami, Y. Nagasaka, T. Nakadaira, T. T. Nakamura, E. Nakano, M. Nakao, H. Nakayama, J. W. Nam, K. Neichi, S. Nishida, O. Nitoh, S. Noguchi, T. Nozaki, S. Ogawa, Y. Ogawa, K. Ohmi, Y. Ohnishi, T. Ohshima, N. Ohuchi, T. Okabe, S. Okuno, S. L. Olsen, Y. Onuki, W. Ostrowicz, H. Ozaki, H. Palka, C. W. Park, H. Park, K. S. Park, L. S. Peak, J. P. Perroud, M. Peters, L. E. Piilonen, M. Rozanska, K. Rybicki, H. Sagawa, S. Saitoh, Y. Sakai, T. R. Sarangi, M. Satapathy, A. Satpathy, O. Schneider, S. Schrenk, J. Schümann, C. Schwanda, S. Semenov, K. Senyo, M. E. Sevior, H. Shibuya, T. Shidara, B. Shwartz, V. Sidorov, J. B. Singh, S. Stanič, M. Starič, R. Sugahara, A. Sugiyama, K. Sumisawa, T. Sumiyoshi, K. Suzuki, S. Suzuki, T. Takahashi, F. Takasaki, K. Tamai, N. Tamura, J. Tanaka, M. Tanaka, M. Tawada, G. N. Taylor, Y. Teramoto, S. Tokuda, T. Tomura, K. Trabelsi, T. Tsuboyama, T. Tsukamoto, S. Uehara, Y. Unno, S. Uno, N. Uozaki, S. E. Vahsen, G. Varner, K. E. Varvell, C. C. Wang, C. H. Wang, J. G. Wang, M. Z. Wang, Y. Watanabe, E. Won, B. D. Yabsley, Y. Yamada, A. Yamaguchi, H. Yamamoto, Y. Yamashita, Y. Yamashita, M. Yamauchi, M. Yokoyama, M. Yoshida, C. C. Zhang, Z. P. Zhang, V. Zhilich, D. Žontar

Research output: Contribution to journal › Article › peer-review

57 Citations (Scopus)

Abstract

We present an improved measurement of CP-violating asymmetries in B ⁰→π ⁺π ^- decays based on a 78 fb ^-1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e ⁺ e ^- collider. We reconstruct one neutral B meson as a B ⁰→π ⁺π ^- CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes A _ππ= +0.77 ±0.27(stat) ±0.08(syst) and S _ππ=-1.23 ±0.41(stat) _-0.07 ^+0.08(syst), where the statistical uncertainties are determined from the Monte Carlo pseudoexperiments. We obtain confidence intervals for CP-violating asymmetry parameters A _ππ and S _ππ based on a frequentist approach. We rule out the CP-conserving case, A _ππ=S _ππ=0, at the 99.93% confidence level. We discuss how these results constrain the value of the Cabibbo-Kobayashi-Maskawa (CKM) angle φ ₂.

Original language	English
Article number	012001
Journal	Physical Review D
Volume	68
Issue number	1
DOIs	https://doi.org/10.1103/PhysRevD.68.012001
Publication status	Published - Jan 1 2003
Externally published	Yes

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)
Physics and Astronomy(all)
Nuclear and High Energy Physics
Mathematical Physics

Access to Document

10.1103/PhysRevD.68.012001

Cite this

Abe, K., Abe, K., Abe, N., Abe, T., Adachi, I., Aihara, H., Akai, K., Akatsu, M., Akemoto, M., Asano, Y., Aushev, T., Bakich, A. M., Ban, Y., Banas, E., Bay, A., Bedny, I., Behera, P. K., Bizjak, I., Bondar, A., ... Žontar, D. (2003). Vidence for CP-violating asymmetries in B ⁰→π ⁺π ^- decays and constraints on the CKM angle φ ₂ Physical Review D, 68(1), [012001]. https://doi.org/10.1103/PhysRevD.68.012001

Abe, K, Abe, K, Abe, N, Abe, T, Adachi, I, Aihara, H, Akai, K, Akatsu, M, Akemoto, M, Asano, Y, Aushev, T, Bakich, AM, Ban, Y, Banas, E, Bay, A, Bedny, I, Behera, PK, Bizjak, I, Bondar, A, Bozek, A, Bračko, M, Brodzicka, J, Browder, TE, Casey, BCK, Chang, P, Chen, KF, Cheon, BG, Chistov, R, Choi, SK, Choi, Y, Choi, YK, Danilov, M, Dragic, J, Drutskoy, A, Eidelman, S, Eiges, V, Everton, CW, Flanagan, J, Fukunaga, C, Furukawa, K, Gabyshev, N, Garmash, A, Gershon, T, Golob, B, Guo, R, Hagner, C, Hara, K, Hastings, NC, Hasuko, K, Hayashii, H, Hazumi, M, Higuchi, T, Hinz, L, Hojo, T, Hokuue, T, Hoshi, Y, Hou, WS, Hsiung, YB, Huang, HC, Igaki, T, Igarashi, Y, Iijima, T, Ikeda, H, Inami, K, Ishikawa, A, Ishino, H, Itoh, R, Iwasaki, H, Iwasaki, Y, Jang, HK, Kang, JS, Kapusta, P, Kataoka, SU, Katayama, N, Katano, G, Kawai, H, Kawamura, N, Kawasaki, T, Kichimi, H, Kikuchi, M, Kikutani, E, Kim, DW, Kim, HJ, Kim, HO, Kim, H, Kim, JH, Kim, SK, Kobayashi, S, Korpar, S, Križan, P, Krokovny, P, Kubo, T, Kulasiri, R, Kumar, S, Kuzmin, A, Kwon, YJ, Lange, JS, Leder, G, Lee, SH, Li, J, Lin, SW, MacNaughton, J, Mandl, F, Marlow, D, Matsumoto, S, Matsumoto, T, Michizono, S, Mimashi, T, Mitaroff, W, Miyabayashi, K, Miyake, H, Miyata, H, Moloney, GR, Mori, T, Murakami, A, Nagasaka, Y, Nakadaira, T, Nakamura, TT, Nakano, E, Nakao, M, Nakayama, H, Nam, JW, Neichi, K, Nishida, S, Nitoh, O, Noguchi, S, Nozaki, T, Ogawa, S, Ogawa, Y, Ohmi, K, Ohnishi, Y, Ohshima, T, Ohuchi, N, Okabe, T, Okuno, S, Olsen, SL, Onuki, Y, Ostrowicz, W, Ozaki, H, Palka, H, Park, CW, Park, H, Park, KS, Peak, LS, Perroud, JP, Peters, M, Piilonen, LE, Rozanska, M, Rybicki, K, Sagawa, H, Saitoh, S, Sakai, Y, Sarangi, TR, Satapathy, M, Satpathy, A, Schneider, O, Schrenk, S, Schümann, J, Schwanda, C, Semenov, S, Senyo, K, Sevior, ME, Shibuya, H, Shidara, T, Shwartz, B, Sidorov, V, Singh, JB, Stanič, S, Starič, M, Sugahara, R, Sugiyama, A, Sumisawa, K, Sumiyoshi, T, Suzuki, K, Suzuki, S, Takahashi, T, Takasaki, F, Tamai, K, Tamura, N, Tanaka, J, Tanaka, M, Tawada, M, Taylor, GN, Teramoto, Y, Tokuda, S, Tomura, T, Trabelsi, K, Tsuboyama, T, Tsukamoto, T, Uehara, S, Unno, Y, Uno, S, Uozaki, N, Vahsen, SE, Varner, G, Varvell, KE, Wang, CC, Wang, CH, Wang, JG, Wang, MZ, Watanabe, Y, Won, E, Yabsley, BD, Yamada, Y, Yamaguchi, A, Yamamoto, H, Yamashita, Y, Yamashita, Y, Yamauchi, M, Yokoyama, M, Yoshida, M, Zhang, CC, Zhang, ZP, Zhilich, V & Žontar, D 2003, 'Vidence for CP-violating asymmetries in B ⁰→π ⁺π ^- decays and constraints on the CKM angle φ ₂ ', Physical Review D, vol. 68, no. 1, 012001. https://doi.org/10.1103/PhysRevD.68.012001

@article{80735b224656408796e1bc7536dc29ed,

title = "Vidence for CP-violating asymmetries in B 0→π +π - decays and constraints on the CKM angle φ 2 ",

abstract = "We present an improved measurement of CP-violating asymmetries in B 0→π +π - decays based on a 78 fb -1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. We reconstruct one neutral B meson as a B 0→π +π - CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes A ππ= +0.77 ±0.27(stat) ±0.08(syst) and S ππ=-1.23 ±0.41(stat) -0.07 +0.08(syst), where the statistical uncertainties are determined from the Monte Carlo pseudoexperiments. We obtain confidence intervals for CP-violating asymmetry parameters A ππ and S ππ based on a frequentist approach. We rule out the CP-conserving case, A ππ=S ππ=0, at the 99.93% confidence level. We discuss how these results constrain the value of the Cabibbo-Kobayashi-Maskawa (CKM) angle φ 2.",

author = "K. Abe and K. Abe and N. Abe and T. Abe and I. Adachi and H. Aihara and K. Akai and M. Akatsu and M. Akemoto and Y. Asano and T. Aushev and Bakich, {A. M.} and Y. Ban and E. Banas and A. Bay and I. Bedny and Behera, {P. K.} and I. Bizjak and A. Bondar and A. Bozek and M. Bra{\v c}ko and J. Brodzicka and Browder, {T. E.} and Casey, {B. C.K.} and P. Chang and Chen, {K. F.} and Cheon, {B. G.} and R. Chistov and Choi, {S. K.} and Y. Choi and Choi, {Y. K.} and M. Danilov and J. Dragic and A. Drutskoy and S. Eidelman and V. Eiges and Everton, {C. W.} and J. Flanagan and C. Fukunaga and K. Furukawa and N. Gabyshev and A. Garmash and T. Gershon and B. Golob and R. Guo and C. Hagner and K. Hara and Hastings, {N. C.} and K. Hasuko and H. Hayashii and M. Hazumi and T. Higuchi and L. Hinz and T. Hojo and T. Hokuue and Y. Hoshi and Hou, {W. S.} and Hsiung, {Y. B.} and Huang, {H. C.} and T. Igaki and Y. Igarashi and T. Iijima and H. Ikeda and K. Inami and A. Ishikawa and H. Ishino and R. Itoh and H. Iwasaki and Y. Iwasaki and Jang, {H. K.} and Kang, {J. S.} and P. Kapusta and Kataoka, {S. U.} and N. Katayama and G. Katano and H. Kawai and N. Kawamura and T. Kawasaki and H. Kichimi and M. Kikuchi and E. Kikutani and Kim, {D. W.} and Kim, {H. J.} and Kim, {H. O.} and H. Kim and Kim, {J. H.} and Kim, {S. K.} and S. Kobayashi and S. Korpar and P. Kri{\v z}an and P. Krokovny and T. Kubo and R. Kulasiri and S. Kumar and A. Kuzmin and Kwon, {Y. J.} and Lange, {J. S.} and G. Leder and Lee, {S. H.} and J. Li and Lin, {S. W.} and J. MacNaughton and F. Mandl and D. Marlow and S. Matsumoto and T. Matsumoto and S. Michizono and T. Mimashi and W. Mitaroff and K. Miyabayashi and H. Miyake and H. Miyata and Moloney, {G. R.} and T. Mori and A. Murakami and Y. Nagasaka and T. Nakadaira and Nakamura, {T. T.} and E. Nakano and M. Nakao and H. Nakayama and Nam, {J. W.} and K. Neichi and S. Nishida and O. Nitoh and S. Noguchi and T. Nozaki and S. Ogawa and Y. Ogawa and K. Ohmi and Y. Ohnishi and T. Ohshima and N. Ohuchi and T. Okabe and S. Okuno and Olsen, {S. L.} and Y. Onuki and W. Ostrowicz and H. Ozaki and H. Palka and Park, {C. W.} and H. Park and Park, {K. S.} and Peak, {L. S.} and Perroud, {J. P.} and M. Peters and Piilonen, {L. E.} and M. Rozanska and K. Rybicki and H. Sagawa and S. Saitoh and Y. Sakai and Sarangi, {T. R.} and M. Satapathy and A. Satpathy and O. Schneider and S. Schrenk and J. Sch{\"u}mann and C. Schwanda and S. Semenov and K. Senyo and Sevior, {M. E.} and H. Shibuya and T. Shidara and B. Shwartz and V. Sidorov and Singh, {J. B.} and S. Stani{\v c} and M. Stari{\v c} and R. Sugahara and A. Sugiyama and K. Sumisawa and T. Sumiyoshi and K. Suzuki and S. Suzuki and T. Takahashi and F. Takasaki and K. Tamai and N. Tamura and J. Tanaka and M. Tanaka and M. Tawada and Taylor, {G. N.} and Y. Teramoto and S. Tokuda and T. Tomura and K. Trabelsi and T. Tsuboyama and T. Tsukamoto and S. Uehara and Y. Unno and S. Uno and N. Uozaki and Vahsen, {S. E.} and G. Varner and Varvell, {K. E.} and Wang, {C. C.} and Wang, {C. H.} and Wang, {J. G.} and Wang, {M. Z.} and Y. Watanabe and E. Won and Yabsley, {B. D.} and Y. Yamada and A. Yamaguchi and H. Yamamoto and Y. Yamashita and Y. Yamashita and M. Yamauchi and M. Yokoyama and M. Yoshida and Zhang, {C. C.} and Zhang, {Z. P.} and V. Zhilich and D. {\v Z}ontar",

year = "2003",

month = jan,

day = "1",

doi = "10.1103/PhysRevD.68.012001",

language = "English",

volume = "68",

journal = "Physical review D: Particles and fields",

issn = "0556-2821",

publisher = "American Physical Society",

number = "1",

}

TY - JOUR

T1 - Vidence for CP-violating asymmetries in B 0→π +π - decays and constraints on the CKM angle φ 2

AU - Abe, K.

AU - Abe, N.

AU - Abe, T.

AU - Adachi, I.

AU - Aihara, H.

AU - Akai, K.

AU - Akatsu, M.

AU - Akemoto, M.

AU - Asano, Y.

AU - Aushev, T.

AU - Bakich, A. M.

AU - Ban, Y.

AU - Banas, E.

AU - Bay, A.

AU - Bedny, I.

AU - Behera, P. K.

AU - Bizjak, I.

AU - Bondar, A.

AU - Bozek, A.

AU - Bračko, M.

AU - Brodzicka, J.

AU - Browder, T. E.

AU - Casey, B. C.K.

AU - Chang, P.

AU - Chen, K. F.

AU - Cheon, B. G.

AU - Chistov, R.

AU - Choi, S. K.

AU - Choi, Y.

AU - Choi, Y. K.

AU - Danilov, M.

AU - Dragic, J.

AU - Drutskoy, A.

AU - Eidelman, S.

AU - Eiges, V.

AU - Everton, C. W.

AU - Flanagan, J.

AU - Fukunaga, C.

AU - Furukawa, K.

AU - Gabyshev, N.

AU - Garmash, A.

AU - Gershon, T.

AU - Golob, B.

AU - Guo, R.

AU - Hagner, C.

AU - Hara, K.

AU - Hastings, N. C.

AU - Hasuko, K.

AU - Hayashii, H.

AU - Hazumi, M.

AU - Higuchi, T.

AU - Hinz, L.

AU - Hojo, T.

AU - Hokuue, T.

AU - Hoshi, Y.

AU - Hou, W. S.

AU - Hsiung, Y. B.

AU - Huang, H. C.

AU - Igaki, T.

AU - Igarashi, Y.

AU - Iijima, T.

AU - Ikeda, H.

AU - Inami, K.

AU - Ishikawa, A.

AU - Ishino, H.

AU - Itoh, R.

AU - Iwasaki, H.

AU - Iwasaki, Y.

AU - Jang, H. K.

AU - Kang, J. S.

AU - Kapusta, P.

AU - Kataoka, S. U.

AU - Katayama, N.

AU - Katano, G.

AU - Kawai, H.

AU - Kawamura, N.

AU - Kawasaki, T.

AU - Kichimi, H.

AU - Kikuchi, M.

AU - Kikutani, E.

AU - Kim, D. W.

AU - Kim, H. J.

AU - Kim, H. O.

AU - Kim, H.

AU - Kim, J. H.

AU - Kim, S. K.

AU - Kobayashi, S.

AU - Korpar, S.

AU - Križan, P.

AU - Krokovny, P.

AU - Kubo, T.

AU - Kulasiri, R.

AU - Kumar, S.

AU - Kuzmin, A.

AU - Kwon, Y. J.

AU - Lange, J. S.

AU - Leder, G.

AU - Lee, S. H.

AU - Li, J.

AU - Lin, S. W.

AU - MacNaughton, J.

AU - Mandl, F.

AU - Marlow, D.

AU - Matsumoto, S.

AU - Matsumoto, T.

AU - Michizono, S.

AU - Mimashi, T.

AU - Mitaroff, W.

AU - Miyabayashi, K.

AU - Miyake, H.

AU - Miyata, H.

AU - Moloney, G. R.

AU - Mori, T.

AU - Murakami, A.

AU - Nagasaka, Y.

AU - Nakadaira, T.

AU - Nakamura, T. T.

AU - Nakano, E.

AU - Nakao, M.

AU - Nakayama, H.

AU - Nam, J. W.

AU - Neichi, K.

AU - Nishida, S.

AU - Nitoh, O.

AU - Noguchi, S.

AU - Nozaki, T.

AU - Ogawa, S.

AU - Ogawa, Y.

AU - Ohmi, K.

AU - Ohnishi, Y.

AU - Ohshima, T.

AU - Ohuchi, N.

AU - Okabe, T.

AU - Okuno, S.

AU - Olsen, S. L.

AU - Onuki, Y.

AU - Ostrowicz, W.

AU - Ozaki, H.

AU - Palka, H.

AU - Park, C. W.

AU - Park, H.

AU - Park, K. S.

AU - Peak, L. S.

AU - Perroud, J. P.

AU - Peters, M.

AU - Piilonen, L. E.

AU - Rozanska, M.

AU - Rybicki, K.

AU - Sagawa, H.

AU - Saitoh, S.

AU - Sakai, Y.

AU - Sarangi, T. R.

AU - Satapathy, M.

AU - Satpathy, A.

AU - Schneider, O.

AU - Schrenk, S.

AU - Schümann, J.

AU - Schwanda, C.

AU - Semenov, S.

AU - Senyo, K.

AU - Sevior, M. E.

AU - Shibuya, H.

AU - Shidara, T.

AU - Shwartz, B.

AU - Sidorov, V.

AU - Singh, J. B.

AU - Stanič, S.

AU - Starič, M.

AU - Sugahara, R.

AU - Sugiyama, A.

AU - Sumisawa, K.

AU - Sumiyoshi, T.

AU - Suzuki, K.

AU - Suzuki, S.

AU - Takahashi, T.

AU - Takasaki, F.

AU - Tamai, K.

AU - Tamura, N.

AU - Tanaka, J.

AU - Tanaka, M.

AU - Tawada, M.

AU - Taylor, G. N.

AU - Teramoto, Y.

AU - Tokuda, S.

AU - Tomura, T.

AU - Trabelsi, K.

AU - Tsuboyama, T.

AU - Tsukamoto, T.

AU - Uehara, S.

AU - Unno, Y.

AU - Uno, S.

AU - Uozaki, N.

AU - Vahsen, S. E.

AU - Varner, G.

AU - Varvell, K. E.

AU - Wang, C. C.

AU - Wang, C. H.

AU - Wang, J. G.

AU - Wang, M. Z.

AU - Watanabe, Y.

AU - Won, E.

AU - Yabsley, B. D.

AU - Yamada, Y.

AU - Yamaguchi, A.

AU - Yamamoto, H.

AU - Yamashita, Y.

AU - Yamauchi, M.

AU - Yokoyama, M.

AU - Yoshida, M.

AU - Zhang, C. C.

AU - Zhang, Z. P.

AU - Zhilich, V.

AU - Žontar, D.

PY - 2003/1/1

Y1 - 2003/1/1

N2 - We present an improved measurement of CP-violating asymmetries in B 0→π +π - decays based on a 78 fb -1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. We reconstruct one neutral B meson as a B 0→π +π - CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes A ππ= +0.77 ±0.27(stat) ±0.08(syst) and S ππ=-1.23 ±0.41(stat) -0.07 +0.08(syst), where the statistical uncertainties are determined from the Monte Carlo pseudoexperiments. We obtain confidence intervals for CP-violating asymmetry parameters A ππ and S ππ based on a frequentist approach. We rule out the CP-conserving case, A ππ=S ππ=0, at the 99.93% confidence level. We discuss how these results constrain the value of the Cabibbo-Kobayashi-Maskawa (CKM) angle φ 2.

AB - We present an improved measurement of CP-violating asymmetries in B 0→π +π - decays based on a 78 fb -1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. We reconstruct one neutral B meson as a B 0→π +π - CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes A ππ= +0.77 ±0.27(stat) ±0.08(syst) and S ππ=-1.23 ±0.41(stat) -0.07 +0.08(syst), where the statistical uncertainties are determined from the Monte Carlo pseudoexperiments. We obtain confidence intervals for CP-violating asymmetry parameters A ππ and S ππ based on a frequentist approach. We rule out the CP-conserving case, A ππ=S ππ=0, at the 99.93% confidence level. We discuss how these results constrain the value of the Cabibbo-Kobayashi-Maskawa (CKM) angle φ 2.

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U2 - 10.1103/PhysRevD.68.012001

DO - 10.1103/PhysRevD.68.012001

M3 - Article

AN - SCOPUS:0041886720

VL - 68

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

IS - 1

M1 - 012001

ER -

Vidence for CP-violating asymmetries in B ⁰→π ⁺π ^- decays and constraints on the CKM angle φ ₂

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