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ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2014, vol. 89, p. -

Evidence for semileptonic B-→ pp̄ℓ- ν̄ℓ decays

Tien K. J., Wang M. Z., Adachi I., Aihara H., Asner D. M., Aulchenko V., Aushev T., Bakich A. M., Bala A., Bhuyan B., Bozek A., Bračko M., Browder T. E., Chang P., Chekelian V., Chen A., Chen P., Cheon B. G., Chilikin K., Chistov R., Cho I. S., Cho K., Chobanova V., Choi Y., Cinabro D., Dalseno J., Danilov M., Doležal Z., Drásal Z., Dutta D., Eidelman S., Farhat H., Fast J. E., Ferber T., Gaur V., Ganguly S., Gillard R., Goh Y. M., Golob B., Haba J., Hayashii H., Horii Y., Hoshi Y., Hou W. S., Hsiung Y. B., Huschle M., Hyun H. J., Iijima T., Ishikawa A., Itoh R., Iwasaki Y., Julius T., Kah D. H., Kang J. H., Kato E., Kawasaki T., Kichimi H., Kiesling C., Kim D. Y., Kim H. J., Kim J. B., Kim J. H., Kim Y. J., Klucar J., Ko B. R., Kodyš P., Korpar S., Križan P., Krokovny P., Kronenbitter B., Kuhr T., Kumita T., Kuzmin A., Kwon Y. J., Lee S. H., Li J., Li Y., Libby J., Liu C., Liu Y., Liventsev D., Lukin P., Miyabayashi K., Miyata H., Mohanty G. B., Moll A., Mussa R., Nakano E., Nakao M., Natkaniec Z., Nayak M., Nedelkovska E.

We find evidence for the semileptonic baryonic decay B-→pp̄ℓ- ν̄ℓ (ℓ=e, μ), based on a data sample of 772 million BB̄ pairs collected at the Ï (4S) resonance with the Belle detector at the KEKB asymmetric-energy electron-positron collider. A neural-network based hadronic B-meson tagging method is used in this study. The branching fraction of B-→pp̄ℓ-ν̄ℓ is measured to be (5.8-2.1+2.4(stat) ±0.9(syst))×10-6 with a significance of 3.2σ, where lepton universality is assumed. We also estimate the corresponding upper limit: B(B-→pp̄ℓ-ν̄ℓ)<9.6×10-6 at the 90% confidence level. This measurement helps constrain the baryonic transition form factor in B decays. © 2014 American Physical Society.