Observation of $\Xi_{c}(2930)^0$ and Updated Measurement of $B^{-} \to K^{-} \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ at Belle

Autor: Li, Y. B., Shen, C. P., Adachi, I., Ahn, J. K., Aihara, H., Al Said, S., Asner, D. M., Aushev, T., Ayad, R., Babu, V., Badhrees, I., Bakich, A. M., Ban, Y., Bansal, V., Behera, P., Berger, M., Bhardwaj, V., Bhuyan, B., Biswal, J., Bonvicini, G., Bozek, A., Bračko, M., Browder, T. E., Červenkov, D., Chekelian, V., Chen, A., Cheon, B. G., Chilikin, K., Cho, K., Choi, S.-K., Choi, Y., Cinabro, D., Cunliffe, S., Dash, N., Di Carlo, S., Doležal, Z., Drásal, Z., Eidelman, S., Epifanov, D., Fast, J. E., Ferber, T., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Gelb, M., Giri, A., Goldenzweig, P., Guido, E., Haba, J., Hara, T., Hayasaka, K., Hayashii, H., Hedges, M. T., Hou, W.-S., Iijima, T., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Jacobs, W. W., Jia, S., Jin, Y., Joo, K. K., Julius, T., Karyan, G., Kato, Y., Kawasaki, T., Kichimi, H., Kiesling, C., Kim, D. Y., Kim, J. B., Kim, K. T., Kim, S. H., Kinoshita, K., Kodyš, P., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krokovny, P., Kulasiri, R., Kumita, T., Kuzmin, A., Kwon, Y.-J., Lee, I. S., Lee, S. C., Li, L. K., Li Gioi, L., Libby, J., Liventsev, D., Lubej, M., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Merola, M., Miyabayashi, K., Miyata, H., Mizuk, R., Mohanty, G. B., Moon, H. K., Mori, T., Mrvar, M., Mussa, R., Nakano, E., Nakao, M., Nanut, T., Nath, K. J., Natkaniec, Z., Nayak, M., Niiyama, M., Nishida, S., Ogawa, S., Pakhlov, P., Pakhlova, G., Pal, B., Pardi, S., Park, C. W., Park, H., Paul, S., Pedlar, T. K., Pestotnik, R., Piilonen, L. E., Popov, V., Rostomyan, A., Russo, G., Sakai, Y., Salehi, M., Sandilya, S., Santelj, L., Sanuki, T., Schneider, O., Schnell, G., Schwanda, C., Seino, Y., Shebalin, V., Shibata, T.-A., Shiu, J.-G., Shwartz, B., Sokolov, A., Solovieva, E., Starič, M., Strube, J. F., Sumihama, M., Sumiyoshi, T., Takizawa, M., Tamponi, U., Tanida, K., Tenchini, F., Uchida, M., Uglov, T., Unno, Y., Uno, S., Van Hulse, C., Varner, G., Vorobyev, V., Vossen, A., Waheed, E., Wang, B., Wang, C. H., Wang, M.-Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Widmann, E., Won, E., Ye, Hua, Yelton, J., Yuan, C. Z., Yusa, Y., Zakharov, S., Zhang, Z. P., Zhilich, V., Zhukova, V., Zhulanov, V.
Jazyk: angličtina
Rok vydání: 2017
Předmět:
DOI: 10.3204/pubdb-2017-14002
Popis: We report the first observation of the $\Xi_{c}(2930)^0$ charmed-strange baryon with a significance greater than 5$\sigma$. The $\Xi_{c}(2930)^0$ is found in its decay to $K^- \Lambda_{c}^+$ in $B^{-} \to K^{-} \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ decays. The measured mass and width are $[2928.9 \pm 3.0(\rm stat.)^{+0.8}_{-12.0}(\rm syst.)]$ MeV/$c^{2}$ and $[19.5 \pm 8.4(\rm stat.) ^{+5.4}_{-7.9}(\rm syst.)]$ MeV, respectively, and the product branching fraction is ${\cal B}(B^{-} \to \Xi_{c}(2930)^0 \bar{\Lambda}_{c}^{-}) {\cal B}(\Xi_{c}(2930)^0 \to K^- \Lambda_{c}^{+})=[1.73 \pm 0.45(\rm stat.) \pm 0.24(\rm syst.)]\times 10^{-4}$. We also measure ${\cal B}(B^{-} \to K^{-} \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}) = [4.80 \pm 0.43(\rm stat.) \pm 0.68(\rm syst.)] \times 10^{-4}$ with improved precision, and 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 $Y(4660)$ 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 $\Upsilon(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
Databáze: OpenAIRE