Observation of $Ξ_{c}(2930)^0$ and updated measurement of $B^{-} \to K^{-} Λ_{c}^{+} \barΛ_{c}^{-}$ at Belle
Creators: name: Belle Collaboration
name: Li, Y. B.
name: Shen, C. P.
name: Adachi, I.
name: Ahn, J. K.
name: Aihara, H.
name: Said, S. Al
name: Asner, D. M.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Badhrees, I.
name: Bakich, A. M.
name: Ban, Y.
name: Bansal, V.
name: Behera, P.
name: Berger, M.
name: Bhardwaj, V.
name: Bhuyan, B.
name: Biswal, J.
name: Bonvicini, G.
name: Bozek, A.
name: Bračko, M.
name: Browder, T. E.
name: Červenkov, D.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Choi, S. -K.
name: Choi, Y.
name: Cinabro, D.
name: Cunliffe, S.
name: Dash, N.
name: Di Carlo, S.
name: Doležal, Z.
name: Drásal, Z.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Ferber, T.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gelb, M.
name: Giri, A.
name: Goldenzweig, P.
name: Guido, E.
name: Haba, J.
name: Hara, T.
name: Hayasaka, K.
name: Hayashii, H.
name: Hedges, M. T.
name: Hou, W. -S.
name: Iijima, T.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jia, S.
name: Jin, Y.
name: Joo, K. K.
name: Julius, T.
name: Karyan, G.
name: Kato, Y.
name: Kawasaki, T.
name: Kichimi, H.
name: Kiesling, C.
name: Kim, D. Y.
name: Kim, J. B.
name: Kim, K. T.
name: Kim, S. H.
name: Kinoshita, K.
name: Kodyš, P.
name: Korpar, S.
name: Kotchetkov, D.
name: Križan, P.
name: Kroeger, R.
name: Krokovny, P.
name: Kulasiri, R.
name: Kumita, T.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lee, I. S.
name: Lee, S. C.
name: Li, L. K.
name: Gioi, L. Li
name: Libby, J.
name: Liventsev, D.
name: Lubej, M.
name: Luo, T.
name: MacNaughton, J.
name: Masuda, M.
name: Matsuda, T.
name: Merola, M.
name: Miyabayashi, K.
name: Miyata, H.
name: Mizuk, R.
name: Mohanty, G. B.
name: Moon, H. K.
name: Mori, T.
name: Mrvar, M.
name: Mussa, R.
name: Nakano, E.
name: Nakao, M.
name: Nanut, T.
name: Nath, K. J.
name: Natkaniec, Z.
name: Nayak, M.
name: Niiyama, M.
name: Nishida, S.
name: Ogawa, S.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pal, B.
name: Pardi, S.
name: Park, C. W.
name: Park, H.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Popov, V.
name: Rostomyan, A.
name: Russo, G.
name: Sakai, Y.
name: Salehi, M.
name: Sandilya, S.
name: Santelj, L.
name: Sanuki, T.
name: Schneider, O.
name: Schnell, G.
name: Schwanda, C.
name: Seino, Y.
name: Shebalin, V.
name: Shibata, T. -A.
name: Shiu, J. -G.
name: Shwartz, B.
name: Sokolov, A.
name: Solovieva, E.
name: Starič, M.
name: Strube, J. F.
name: Sumihama, M.
name: Sumiyoshi, T.
name: Takizawa, M.
name: Tamponi, U.
name: Tanida, K.
name: Tenchini, F.
name: Uchida, M.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Van Hulse, C.
name: Varner, G.
name: Vorobyev, V.
name: Vossen, A.
name: Waheed, E.
name: Wang, B.
name: Wang, C. H.
name: Wang, M. -Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Watanabe, Y.
name: Widmann, E.
name: Won, E.
name: Ye, H.
name: Yelton, J.
name: Yuan, C. Z.
name: Yusa, Y.
name: Zakharov, S.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the first observation of the $Ξ_{c}(2930)^0$ charmed-strange baryon with a significance greater than 5$σ$. The $Ξ_{c}(2930)^0$ is found in its decay to $K^- Λ_{c}^+$ in $B^{-} \to K^{-} Λ_{c}^{+} \barΛ_{c}^{-}$ decays. The measured mass and width are $[2928.9 \pm 3.0(\rm stat.)^{+0.9}_{-12.0}(\rm syst.)]$ MeV/$c^{2}$ and $[19.5 \pm 8.4(\rm stat.) ^{+5.9}_{-7.9}(\rm syst.)]$ MeV, respectively, and the product branching fraction is ${\cal B}(B^{-} \to Ξ_{c}(2930)^0 \barΛ_{c}^{-}) {\cal B}(Ξ_{c}(2930)^0 \to K^- Λ_{c}^{+})=[1.73 \pm 0.45(\rm stat.) \pm 0.21(\rm syst.)]\times 10^{-4}$. We also measure ${\cal B}(B^{-} \to K^{-} Λ_{c}^{+} \barΛ_{c}^{-}) = [4.80 \pm 0.43(\rm stat.) \pm 0.60(\rm syst.)] \times 10^{-4}$ with improved precision, and search for the charmonium-like state $Y(4660)$ and its spin partner, $Y_η$, in the $Λ_{c}^{+}\barΛ_{c}^{-}$ invariant mass spectrum. No clear signals of the $Y(4660)$ nor its spin partner are observed and the 90\% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $(772\pm11)\times 10^{6} B\bar{B}$ pairs collected at the $Υ(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
description: 7 pages, 5 figures; accepted for publication in European Physical Journal C