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Difference in direct charge-parity violation between charged and neutral B meson decays

Nature volume 452, pages 332–335 (2008)Cite this article

Abstract

Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter-dominated. One of the prerequisites1 for understanding this elimination of antimatter is the nonconservation of charge-parity (CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson (K0) and B meson (B0) systems: CP violation involving the mixing2 between K0 and its antiparticle (and likewise3,4 for B0 and ), and direct CP violation in the decay of each meson5,6,7,8. The observed effects for both types of CP violation are substantially larger for the B0 meson system. However, they are still consistent with the standard model of particle physics, which has a unique source9 of CP violation that is known to be too small10 to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B±→K±π0 decay is different from that in the neutral B0 counterpart. The direct CP-violating decay rate asymmetry, (that is, the difference between the number of observed B-→K-π0 event versus B+→K+ π0 events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement7. However, the asymmetry for versus B0→K+π- is at the -10% level7,8. Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation—which would help to explain the dominance of matter in the Universe.

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Figure 1: Feynman diagrams for B → Kπ, ππ.
Figure 2: Mbc projections for K-π+ (a), K+π- (b), K-π0 (c) and K+π0 (d).

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Acknowledgements

We thank the KEKB group for the operation of the accelerator, the KEK Cryogenics group for the operation of the solenoid, and the KEK computer group and the NII for computing and Super-SINET network support. We acknowledge support from MEXT and JSPS (Japan); ARC and DEST (Australia); NSFC and KIP of CAS (China); DST (India); MOEHRD, KOSEF and KRF (Korea); KBN (Poland); MES and RFAAE (Russia); ARRS (Slovenia); SNSF (Switzerland); NSC and MOE (Taiwan); and the DOE (USA).

Author information

Authors and Affiliations

  1. Department of Physics, National Taiwan University, Taipei, 106, Taiwan.,

    S.-W. Lin, W.-S. Hou, P. Chang, Y. Chao, K.-F. Chen, C.-C. Chiang, Y. B. Hsiung, J.-G. Shiu, K. Ueno, C. C. Wang & M.-Z. Wang

  2. Hanyang University, Seoul, 133-791, Korea.,

    Y. Unno & B. G. Cheon

  3. High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan.,

    I. Adachi, K. Akai, K. Furukawa, J. Haba, M. Hazumi, R. Itoh, Y. Iwasaki, A. Kibayashi, H. Kichimi, E. Kikutani, P. Krokovny, T. Mimashi, T. T. Nakamura, M. Nakao, S. Nishida, T. Nozaki, Y. Ogawa, H. Ozaki, Y. Sakai, J. Schümann, T. Shidara, K. Sumisawa, O. Tajima, F. Takasaki, M. Tanaka, M. Tawada, K. Trabelsi, S. Uehara, S. Uno, Y. Ushiroda, M. Yamauchi & M. Yoshida

  4. Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan.,

    H. Aihara & M. Iwasaki

  5. Budker Institute of Nuclear Physics, Novosibirsk, 630090, Russian Federation, Russia.,

    K. Arinstein, V. Aulchenko, I. Bedny, A. Bondar, S. Eidelman, D. Epifanov, N. Gabyshev, A. Kuzmin, A. Poluektov, B. Shwartz, Y. Usov, V. Zhilich & V. Zhulanov

  6. Swiss Federal Institute of Technology of Lausanne, EPFL, Lausanne, CH-1015, Switzerland.,

    T. Aushev, A. Bay, O. Schneider, K. Vervink, S. Villa & J. Wicht

  7. Institute for Theoretical and Experimental Physics, Moscow, 117218, Russia.,

    T. Aushev, V. Balagura, R. Chistov, M. Danilov, D. Liventsev, T. Medvedeva, R. Mizuk, G. Pakhlova, I. Tikhomirov & T. Uglov

  8. Tata Institute of Fundamental Research, Mumbai, 400005, India.,

    T. Aziz

  9. University of Sydney, Sydney, New South Wales, 2006, Australia.,

    A. M. Bakich, S. Cole, S. McOnie, L. S. Peak, K. E. Varvell & B. D. Yabsley

  10. University of Melbourne, School of Physics, Victoria 3010, Australia.,

    E. Barberio, J. Dalseno, M. E. Sevior, G. N. Taylor, P. Urquijo & R. Wedd

  11. J. Stefan Institute, Ljubljana, SI-1001, Slovenia.,

    U. Bitenc, M. Bračko, S. Fratina, B. Golob, S. Korpar, R. Pestotnik, M. Starič & A. Zupanc

  12. H. Niewodniczanski Institute of Nuclear Physics, Krakow, 31-342, Poland.,

    A. Bozek & T. Lesiak

  13. University of Maribor, Maribor, SI-2000, Slovenia.,

    M. Bračko & S. Korpar

  14. University of Hawaii, Honolulu, Hawaii 96822, USA.,

    T. E. Browder, J. Li, S. L. Olsen, M. Peters, H. Sahoo & G. Varner

  15. Department of Physics, Fu Jen Catholic University, Taipei, 242, Taiwan.,

    M.-C. Chang

  16. National Central University, Chung-li, 32054, Taiwan.,

    A. Chen, W. T. Chen, C. C. Kuo & H. Nakazawa

  17. Yonsei University, Seoul, 120-749, Korea.,

    I.-S. Cho & Y.-J. Kwon

  18. Gyeongsang National University, Jinju, 660-701, South Korea.,

    S.-K. Choi

  19. Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Korea.,

    Y. Choi, Y. K. Choi & C. W. Park

  20. Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.,

    M. Dash, L. E. Piilonen & Y. Yusa

  21. University of Cincinnati, Cincinnati, Ohio 45221, USA.,

    A. Drutskoy, P. Goldenzweig, K. Kinoshita, A. J. Schwartz & A. Somov

  22. Nara Women’s University, Nara, 630-8506, Japan.,

    M. Fujikawa, H. Hayashii, S. U. Kataoka, K. Miyabayashi & S. Noguchi

  23. Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, SI-1001, Slovenia.,

    B. Golob & P. Križan

  24. Korea University, Seoul, 136-701, Korea.,

    H. Ha & E. Won

  25. Osaka University, Osaka, 560-0043, Japan.,

    T. Hara, D. Heffernan, H. Miyake & S. Shinomiya

  26. Nagoya University, Nagoya, 464-8602, Japan.,

    K. Hayasaka, T. Hokuue, T. Iijima, K. Ikado, K. Inami, H. Kaji, Y. Kozakai, Y. Miyazaki, T. Mori, T. Ohshima & K. Senyo

  27. Tohoku Gakuin University, Tagajo, 985-8537, Japan.,

    Y. Hoshi

  28. Kyungpook National University, Daegu, 702-701, South Korea.,

    H. J. Hyun, D. H. Kah, H. J. Kim & H. Park

  29. Saga University, Saga, 840-8502, Japan.,

    A. Ishikawa & S. Suzuki

  30. Tokyo Institute of Technology, Tokyo, 152-8551, Japan.,

    H. Ishino

  31. The Graduate University for Advanced Studies, Hayama, 240-0193, Japan.,

    M. Iwabuchi, Y. J. Kim & Y. Liu

  32. Chiba University, Chiba, 263-8522, Japan.,

    H. Kawai

  33. Niigata University, Niigata, 950-2181, Japan.,

    T. Kawasaki & N. Tamura

  34. Seoul National University, Seoul, 151-742, Korea.,

    S. K. Kim, M. J. Lee & S. E. Lee

  35. Panjab University, Chandigarh, 160014, India.,

    R. Kumar & J. B. Singh

  36. Institute of High Energy Physics, Vienna, A-1050, Austria.,

    F. Mandl & W. Mitaroff

  37. Princeton University, Princeton, New Jersey 08544, USA.,

    D. Marlow

  38. Osaka City University, Osaka, 558-8585, Japan.,

    E. Nakano & Y. Teramoto

  39. Tokyo University of Agriculture and Technology, Tokyo, 184-8588, Japan.,

    O. Nitoh

  40. Toho University, Funabashi, 274-8510, Japan.,

    S. Ogawa & H. Shibuya

  41. Kanagawa University, Yokohama, 221-8686, Japan.,

    S. Okuno & Y. Watanabe

  42. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.,

    S. L. Olsen, C. P. Shen, C. Z. Yuan & C. C. Zhang

  43. University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.,

    R. Seidl

  44. RIKEN BNL Research Center, Upton, New York 11973, USA.,

    R. Seidl

  45. Institute of High Energy Physics, Protvino, 142281, Russia.,

    M. Shapkin & A. Sokolov

  46. University of Nova Gorica, Nova Gorica, 301 5000, Slovenia.,

    S. Stanič

  47. Tokyo Metropolitan University, Tokyo, 192-0397, Japan.,

    T. Sumiyoshi

  48. National United University, Miao Li, 36003, Taiwan.,

    C. H. Wang

  49. Tohoku University, Sendai, 980-8578, Japan.,

    A. Yamaguchi

  50. Nippon Dental University, Niigata, 951-8580, Japan.,

    Y. Yamashita

  51. University of Science and Technology of China, Hefei, 230026, China.,

    Z. P. Zhang

Consortia

The Belle Collaboration

  • S.-W. Lin
  • , Y. Unno
  • , W.-S. Hou
  • , P. Chang
  • , I. Adachi
  • , H. Aihara
  • , K. Akai
  • , K. Arinstein
  • , V. Aulchenko
  • , T. Aushev
  • , T. Aziz
  • , A. M. Bakich
  • , V. Balagura
  • , E. Barberio
  • , A. Bay
  • , I. Bedny
  • , U. Bitenc
  • , A. Bondar
  • , A. Bozek
  • , M. Bračko
  • , T. E. Browder
  • , M.-C. Chang
  • , Y. Chao
  • , A. Chen
  • , K.-F. Chen
  • , W. T. Chen
  • , B. G. Cheon
  • , C.-C. Chiang
  • , R. Chistov
  • , I.-S. Cho
  • , S.-K. Choi
  • , Y. Choi
  • , Y. K. Choi
  • , S. Cole
  • , J. Dalseno
  • , M. Danilov
  • , M. Dash
  • , A. Drutskoy
  • , S. Eidelman
  • , D. Epifanov
  • , S. Fratina
  • , M. Fujikawa
  • , K. Furukawa
  • , N. Gabyshev
  • , P. Goldenzweig
  • , B. Golob
  • , H. Ha
  • , J. Haba
  • , T. Hara
  • , K. Hayasaka
  • , H. Hayashii
  • , M. Hazumi
  • , D. Heffernan
  • , T. Hokuue
  • , Y. Hoshi
  • , Y. B. Hsiung
  • , H. J. Hyun
  • , T. Iijima
  • , K. Ikado
  • , K. Inami
  • , A. Ishikawa
  • , H. Ishino
  • , R. Itoh
  • , M. Iwabuchi
  • , M. Iwasaki
  • , Y. Iwasaki
  • , D. H. Kah
  • , H. Kaji
  • , S. U. Kataoka
  • , H. Kawai
  • , T. Kawasaki
  • , A. Kibayashi
  • , H. Kichimi
  • , E. Kikutani
  • , H. J. Kim
  • , S. K. Kim
  • , Y. J. Kim
  • , K. Kinoshita
  • , S. Korpar
  • , Y. Kozakai
  • , P. Križan
  • , P. Krokovny
  • , R. Kumar
  • , C. C. Kuo
  • , A. Kuzmin
  • , Y.-J. Kwon
  • , M. J. Lee
  • , S. E. Lee
  • , T. Lesiak
  • , J. Li
  • , Y. Liu
  • , D. Liventsev
  • , F. Mandl
  • , D. Marlow
  • , S. McOnie
  • , T. Medvedeva
  • , T. Mimashi
  • , W. Mitaroff
  • , K. Miyabayashi
  • , H. Miyake
  • , Y. Miyazaki
  • , R. Mizuk
  • , T. Mori
  • , T. T. Nakamura
  • , E. Nakano
  • , M. Nakao
  • , H. Nakazawa
  • , S. Nishida
  • , O. Nitoh
  • , S. Noguchi
  • , T. Nozaki
  • , S. Ogawa
  • , Y. Ogawa
  • , T. Ohshima
  • , S. Okuno
  • , S. L. Olsen
  • , H. Ozaki
  • , G. Pakhlova
  • , C. W. Park
  • , H. Park
  • , L. S. Peak
  • , R. Pestotnik
  • , M. Peters
  • , L. E. Piilonen
  • , A. Poluektov
  • , H. Sahoo
  • , Y. Sakai
  • , O. Schneider
  • , J. Schümann
  • , A. J. Schwartz
  • , R. Seidl
  • , K. Senyo
  • , M. E. Sevior
  • , M. Shapkin
  • , C. P. Shen
  • , H. Shibuya
  • , T. Shidara
  • , S. Shinomiya
  • , J.-G. Shiu
  • , B. Shwartz
  • , J. B. Singh
  • , A. Sokolov
  • , A. Somov
  • , S. Stanič
  • , M. Starič
  • , K. Sumisawa
  • , T. Sumiyoshi
  • , S. Suzuki
  • , O. Tajima
  • , F. Takasaki
  • , N. Tamura
  • , M. Tanaka
  • , M. Tawada
  • , G. N. Taylor
  • , Y. Teramoto
  • , I. Tikhomirov
  • , K. Trabelsi
  • , S. Uehara
  • , K. Ueno
  • , T. Uglov
  • , S. Uno
  • , P. Urquijo
  • , Y. Ushiroda
  • , Y. Usov
  • , G. Varner
  • , K. E. Varvell
  • , K. Vervink
  • , S. Villa
  • , C. C. Wang
  • , C. H. Wang
  • , M.-Z. Wang
  • , Y. Watanabe
  • , R. Wedd
  • , J. Wicht
  • , E. Won
  • , B. D. Yabsley
  • , A. Yamaguchi
  • , Y. Yamashita
  • , M. Yamauchi
  • , M. Yoshida
  • , C. Z. Yuan
  • , Y. Yusa
  • , C. C. Zhang
  • , Z. P. Zhang
  • , V. Zhilich
  • , V. Zhulanov
  •  & A. Zupanc

Corresponding author

Correspondence to P. Chang.

Supplementary information

Supplementary Information

The file contains Supplementary Notes with Supplementary Figures 1-2 and Supplementary Table 1. The text describes the Belle detector, explains how signals are extracted and lists the systematic uncertainties of the measurements. (PDF 722 kb)

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The Belle Collaboration. Difference in direct charge-parity violation between charged and neutral B meson decays. Nature 452, 332–335 (2008). https://doi.org/10.1038/nature06827

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