Evidence for B- -> Ds+ K- l- nubar and search for B- -> Ds+ K- l- nubar

• Published in: arXiv.org 2012-10
• Main Authors: Stypula, J, Rozanska, M, Adamczyk, K, Aihara, H, Asner, D M, Bakich, A M, Bhardwaj, V, Bhuyan, B, Bischofberger, M, Bondar, A, M Bra\v, M -C Chang, Chang, P, Chekelian, V, Chen, P, Cheon, B G, Choi, Y, Z Dole\v, Drásal, Z, Farhat, H, Gaur, V, Gillard, R, Goh, Y M, Golob, B, Hayasaka, K, Horii, Y, Hoshi, Y, Hyun, H J, Inami, K, Itoh, R, Iwabuchi, M, Iwasaki, Y, Kang, J H, Kapusta, P, Kiesling, C, Kim, J H, Kim, K T, Kim, Y J, Kinoshita, K, Ko, B R, P Kody\v, Korpar, S, Kouzes, R T, P Kri\v, Krokovny, P, Kuzmin, A, Y -J Kwon, S -H Lee, Y Li, Libby, J, Liu, Z Q, Liventsev, D, Louvot, R, Miyata, H, Miyazaki, Y, Moll, A, Muramatsu, N, Nakano, E, Nakao, M, Natkaniec, Z, Nishida, S, Nishimura, K, Nitoh, O, Nozaki, T, Ogawa, S, Okuno, S, Olsen, S L, Onuki, Y, Pakhlov, P, Park, C W, Pedlar, T K, M Petri\v, Röhrken, M, Santel, D, Sanuki, T, Schneider, O, Senyo, K, Seon, O, Shen, C P, Smerkol, P, Y -S Sohn, Solovieva, E, S Stani\v, M Stari\v, Sumiyoshi, T, Uchida, M, Uglov, T, Unno, Y, Usov, Y, Vanhoefer, P, Varvell, K E, Vorobyev, V, Wang, P, Wang, X L, Watanabe, M, Watanabe, Y, Williams, K M, Won, E, Yamamoto, H, Yamashita, Y
• Format: Article
• Language: English
• Subjects: Confidence intervals; Decay; Mass distribution
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1207.6244

We report measurements of the decays B- -> Ds(*)+ K- l- nubar in a data sample containing 657x10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe a signal with a significance of 6 sigma for the combined Ds and Ds* modes and find the first evidence of the B- -> Ds+ K- l- nubar decay with a significance of 3.4 sigma. We measure the following branching fractions: BF(B- -> Ds+ K- l nubar) = (0.30 +/- 0.09(stat) +0.11 -0.08(syst)) x 10^-3 and BF(B- -> Ds*+ K- l- nubar) = (0.59 +/- 0.12(stat) +/- 0.15(syst)) x 10^-3 and set an upper limit BF(B- -> Ds*+ K- l- nubar) < 0.56 x 10^-3 at the 90% confidence level. We also present the first measurement of the Ds+K- invariant mass distribution in these decays, which is dominated by a prominent peak around 2.6 GeV/c^2.