Evidence of a structure in anti-K0 Λc+ consistent with a charged Ξc(2930)+, and updated measurement of anti-B0→anti-K0 Λc+Λc- at Belle

Y. B., Li; Shen, C. P.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Aushev, T.; Ayad, R.; Babu, V.; Badhrees, I.; Bahinipati, S.; Ban, Y.; Bansal, V.; Behera, P.; Beleño, C.; Bhardwaj, V.; Bhuyan, B.; Biswal, J.; Bobrov, A.; Bozek, A.; Bračko, M.; Browder, T. E.; Cao, L.; Červenkov, D.; Chang, P.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Cho, K.; Choi, S. -K.; Choi, Y.; Choudhury, S.; Cinabro, D.; Cunliffe, S.; Dash, N.; Di Carlo, S.; Dingfelder, J.; Doležal, Z.; Dong, T. V.; Drásal, Z.; Eidelman, S.; Epifanov, D.; Fast, J. E.; Fulsom, B. G.; Garg, R.; Gaur, V.; Gabyshev, N.; Garmash, A.; Gelb, M.; Giri, A.; Goldenzweig, P.; Golob, B.; Haba, J.; Hayasaka, K.; Hirose, S.; Hou, W. -S.; Iijima, T.; Inami, K.; Inguglia, G.; Ishikawa, A.; Itoh, R.; Iwasaki, M.; Iwasaki, Y.; Jacobs, W. W.; Jaegle, I.; Jeon, H. B.; Jia, S.; Jin, Y.; Joo, K. K.; Kaliyar, A. B.; Kang, K. H.; Kato, Y.; Kawasaki, T.; Kim, D. Y.; Kim, J. B.; Kim, S. H.; Kinoshita, K.; Kodyš, P.; Korpar, S.; Kotchetkov, D.; Križan, P.; Kroeger, R.; Krokovny, P.; Kuhr, T.; Kwon, Y. -J.; Lange, J. S.; Lee, I. S.; Lee, S. C.; L. K., Li; Li Gioi, L.; Libby, J.; Liventsev, D.; Luo, T.; Matvienko, D.; Merola, M.; Miyata, H.; Mizuk, R.; Moon, H. K.; Mori, T.; Mussa, R.; Nakano, E.; Nanut, T.; Nath, K. J.; Natkaniec, Z.; Nayak, M.; Nisar, N. K.; Nishida, S.; Nishimura, K.; Ogawa, K.; Okuno, S.; Ono, H.; Pakhlov, P.; Pakhlova, G.; Pal, B.; Pardi, S.; Park, H.; Paul, S.; Pedlar, T. K.; Pestotnik, R.; Piilonen, L. E.; Popov, V.; Prencipe, E.; Rostomyan, A.; Russo, G.; Sakai, Y.; Salehi, M.; Sandilya, S.; Santelj, L.; Sanuki, T.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Seon, O.; Sevior, M. E.; Shibata, T. -A.; Shiu, J. -G.; 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.; Usov, Y.; Van Hulse, C.; Van Tonder, R.; Varner, G.; Varvell, K. E.; Vorobyev, V.; Waheed, E.; Wang, B.; Wang, C. H.; Wang, M. -Z.; Wang, P.; Wang, X. L.; Watanuki, S.; Widmann, E.; Won, E.; Ye, H.; Yelton, J.; Yin, J. H.; Yuan, C. Z.; Yusa, Y.; Zhang, Z. P.; Zhilich, V.; Zhukova, V.; Zhulanov, V.

doi:10.1140/epjc/s10052-018-6425-5

We report evidence for the charged charmed-strange baryon Ξc(2930)+ with a signal significance of 3.9σ with systematic errors included. The charged Ξc(2930)+ is found in its decay to K0SΛc+ in the substructure of B0→K0Λc+Λc−decays. The measured mass and width are [2942.3±4.4(stat.)±1.5(syst.)]~MeV/c2 and [14.8±8.8(stat.)±2.5(syst.)]~MeV, respectively, and the product branching fraction is B(B0→Ξc(2930)+Λc-)B(Ξc(2930)+→K0Λc-)=[2.37±0.51(stat.)±0.31(syst.)]×10−4. We also measure B(B0→K0Λc+Λc−)=[3.99±0.76(stat.)±0.51(syst.)]×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, Yη, in the Λc+Λc- invariant mass spectrum. No clear signals of the Y(4660) or Yη 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±11)×10^6 BB pairs collected at the Υ(4S) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.