Observation of B0→ΛΛ̄K0 and B0→Λ Λ̄K*0 at Belle

Y. W. Chang, M. Z. Wang, I. Adachi, H. Aihara, T. Aushev, A. M. Bakich, V. Balagura, A. Bay, V. Bhardwaj, U. Bitenc, A. Bondar, A. Bozek, M. Bračko, T. E. Browder, Y. Chao, A. Chen, R. Chistov, Y. Choi, J. Dalseno, M. DanilovM. Dash, A. Drutskoy, S. Eidelman, P. Goldenzweig, H. Ha, B. Y. Han, T. Hara, K. Hayasaka, H. Hayashii, M. Hazumi, D. Heffernan, Y. Horii, Y. Hoshi, W. S. Hou, H. J. Hyun, K. Inami, A. Ishikawa, M. Iwasaki, Y. Iwasaki, N. J. Joshi, D. H. Kah, J. H. Kang, H. Kawai, T. Kawasaki, H. Kichimi, H. J. Kim, Y. I. Kim, Y. J. Kim, B. R. Ko, S. Korpar, P. Križan, Youngjoon Kwon, S. H. Kyeong, J. S. Lee, M. J. Lee, S. E. Lee, T. Lesiak, A. Limosani, S. W. Lin, C. Liu, Y. Liu, R. Louvot, F. Mandl, A. Matyja, S. McOnie, K. Miyabayashi, H. Miyata, Y. Miyazaki, R. Mizuk, Y. Nagasaka, M. Nakao, Z. Natkaniec, S. Nishida, O. Nitoh, S. Ogawa, S. Okuno, H. Ozaki, P. Pakhlov, G. Pakhlova, C. W. Park, H. K. Park, K. S. Park, L. S. Peak, R. Pestotnik, L. E. Piilonen, M. Rozanska, H. Sahoo, Y. Sakai, O. Schneider, A. Sekiya, K. Senyo, M. Shapkin, J. G. Shiu, B. Shwartz, J. B. Singh, S. Stanič, M. Starič, K. Sumisawa, M. Tanaka, G. N. Taylor, Y. Teramoto, I. Tikhomirov, S. Uehara, T. Uglov, Y. Unno, S. Uno, Y. Usov, G. Varner, K. Vervink, C. H. Wang, P. Wang, X. L. Wang, Y. Watanabe, R. Wedd, J. T. Wei, E. Won, B. D. Yabsley, Y. Yamashita, Z. P. Zhang, V. Zhilich, T. Zivko, A. Zupanc, O. Zyukova

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Abstract

We study the charmless decays B→ΛΛ̄h, where h stands for π+, K+, K0,K*+, or K*0, using a 605fb-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We observe B0→ΛΛ̄K0 and B0→ΛΛ̄K*0 with branching fractions of (4.76-0.68+0.84(stat)±0.61(syst))×10-6 and (2.46-0.72+0. 87±0.34)×10-6, respectively. The significances of these signals in the threshold-mass enhanced mass region, MΛΛ̄<2.85GeV/c2, are 12.4σ and 9.3σ, respectively. We also update the branching fraction B(B+→ΛΛ̄K+)=(3.38-0.36+0.41±0.41) ×10-6 with better accuracy, and report the following measurement or 90% confidence level upper limit in the threshold-mass-enhanced region: B(B+→ΛΛ̄K*+)=(2.19-0.88+1.13±0.33) ×10-6 with 3.7σ significance; B(B+→ΛΛ̄π+) <0.94×10-6. A related search for B0→ΛΛ̄D̄0 yields a branching fraction B(B0→ΛΛ̄D̄0)=(1.05-0. 44+0.57±0.14)×10-5. This may be compared with the large, ∼10-4, branching fraction observed for B0→pp̄D̄0. The MΛΛ̄ enhancements near threshold and related angular distributions for the observed modes are also reported.

Original languageEnglish
Article number052006
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume79
Issue number5
DOIs
Publication statusPublished - 2009 Mar 2

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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    Chang, Y. W., Wang, M. Z., Adachi, I., Aihara, H., Aushev, T., Bakich, A. M., Balagura, V., Bay, A., Bhardwaj, V., Bitenc, U., Bondar, A., Bozek, A., Bračko, M., Browder, T. E., Chao, Y., Chen, A., Chistov, R., Choi, Y., Dalseno, J., ... Zyukova, O. (2009). Observation of B0→ΛΛ̄K0 and B0→Λ Λ̄K*0 at Belle. Physical Review D - Particles, Fields, Gravitation and Cosmology, 79(5), [052006]. https://doi.org/10.1103/PhysRevD.79.052006