Evidence of a structure in $\bar{K}^{0} \Lambda _{c}^{+}$ consistent with a charged $\Xi _c(2930)^{+}$, and updated measurement of $\bar{B}^{0} \rightarrow \bar{K}^{0} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}$ at Belle

• Published in: The European physical journal. C, Particles and fields Vol. 78; no. 11
• Main Authors: Shen, C. P., Adachi, I., Ayad, R., Babu, V., Ban, Y., Bansal, V., Behera, P., Beleño, C., Bhuyan, B., Bobrov, A., Bozek, A., Bračko, M., Browder, T. E., Cao, L., Chekelian, V., Cheon, B. G., Choi, Y., Choudhury, S., Cinabro, D., Di Carlo, S., Dingfelder, J., Doležal, Z., Eidelman, S., Epifanov, D., Fast, J. E., Gabyshev, N., Garmash, A., Gelb, M., Giri, A., Golob, B., Haba, J., Hayasaka, K., Hirose, S., Hou, W. -S., Iijima, T., Inguglia, G., Itoh, R., Iwasaki, M., Jaegle, I., Jeon, H. B., Jin, Y., Joo, K. K., Kang, K. H., Kato, Y., Kawasaki, T., Kim, D. Y., Kinoshita, K., Kodyš, P., Korpar, S., Križan, P., Kroeger, R., Kwon, Y. -J., Lange, J. S., Lee, I. S., Libby, J., Liventsev, D., Luo, T., Matvienko, D., Miyata, H., Mizuk, R., Moon, H. K., Mussa, R., Nakano, E., Natkaniec, Z., Nayak, M., Ogawa, K., Okuno, S., Ono, H., Pal, B., Pardi, S., Park, H., Paul, S., Pestotnik, R., Rostomyan, A., Sakai, Y., Salehi, M., Sandilya, S., Santelj, L., Schwanda, C., Seino, Y., Senyo, K., Seon, O., Strube, J. F., Sumihama, M., Tanida, K., Tenchini, F., Uchida, M., Uglov, T., Uno, S., Van Tonder, R., Varner, G., Wang, M. -Z., Wang, P., Wang, X. L., Watanuki, S., Ye, H., Zhang, Z. P., Zhilich, V., Zhukova, V., Zhulanov, V.
• Format: Journal Article
• Language: English
• Published: United States Springer 13.11.2018
• Subjects: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 1434-6044; 1434-6052

We report evidence for the charged charmed-strange baryon \(\Xi _{c}(2930)^+\) with a signal significance of 3.9 \(\sigma \) with systematic errors included. The charged \(\Xi _{c}(2930)^+\) is found in its decay to \(K_{S}^{0} \Lambda _{c}^+\) in the substructure of \(\bar{B}^{0} \rightarrow K^{0}_{S} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}\) decays. The measured mass and width are \([2942.3 \pm 4.4 ({\mathrm{stat.}}) \pm {1.5}({\mathrm{syst.}})]\) MeV/ \(c^{2}\) and \([14.8 \pm 8.8({\mathrm{stat.}}) \pm {2.5}({\mathrm{syst.}})]\) MeV, respectively, and the product branching fraction is \(\mathcal{B}(\bar{B}^{0} \rightarrow \Xi _c(2930)^{+} \bar{\Lambda }_{c}^{-}) \mathcal{B}(\Xi _c(2930)^{+}\rightarrow \bar{K}^{0} \Lambda _{c}^{+})=[2.37 \pm 0.51 ({\mathrm{stat.}})\pm 0.31({\mathrm{syst.}})]\times 10^{-4}\) . We also measure \(\mathcal{B}(\bar{B}^{0} \rightarrow \bar{K}^{0} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}) = [3.99 \pm 0.76({\mathrm{stat.}}) \pm 0.51({\mathrm{syst.}})] \times 10^{-4}\) with greater precision than previous experiments, and present the results of a search for the charmonium-like state Y(4660) and its spin partner, \(Y_{\eta }\) , in the \(\Lambda _{c}^{+}\bar{\Lambda }_{c}^{-}\) invariant mass spectrum. No clear signals of the Y(4660) or \(Y_{\eta }\) 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 \((772\pm 11)\times 10^{6} B\bar{B}\) pairs collected at the \(\Upsilon (4S)\) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.