European Physical Journal C: Particles and Fields (2018-11-01)

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

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

DOI
https://doi.org/10.1140/epjc/s10052-018-6425-5
Journal volume & issue
Vol. 78, no. 11
pp. 1 – 8

Abstract

Read online

Abstract We report evidence for the charged charmed-strange baryon $$\Xi _{c}(2930)^+$$ Ξc(2930)+ with a signal significance of 3.9$$\sigma $$ σ with systematic errors included. The charged $$\Xi _{c}(2930)^+$$ Ξc(2930)+ is found in its decay to $$K_{S}^{0} \Lambda _{c}^+$$ KS0Λc+ in the substructure of $$\bar{B}^{0} \rightarrow K^{0}_{S} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}$$ B¯0→KS0Λc+Λ¯c- decays. The measured mass and width are $$[2942.3 \pm 4.4 ({\mathrm{stat.}}) \pm {1.5}({\mathrm{syst.}})]$$ [2942.3±4.4(stat.)±1.5(syst.)] MeV/$$c^{2}$$ c2 and $$[14.8 \pm 8.8({\mathrm{stat.}}) \pm {2.5}({\mathrm{syst.}})]$$ [14.8±8.8(stat.)±2.5(syst.)] MeV, respectively, and the product branching fraction is $$\mathcal{B}(\bar{B}^{0} \rightarrow \Xi _c(2930)^{+} \bar{\Lambda }_{c}^{-}) \mathcal{B}(\Xi _c(2930)^{+}\rightarrow \bar{K}^{0} \Lambda _{c}^{+})=[2.37 \pm 0.51 ({\mathrm{stat.}})\pm 0.31({\mathrm{syst.}})]\times 10^{-4}$$ B(B¯0→Ξc(2930)+Λ¯c-)B(Ξc(2930)+→K¯0Λc+)=[2.37±0.51(stat.)±0.31(syst.)]×10-4 . We also measure $$\mathcal{B}(\bar{B}^{0} \rightarrow \bar{K}^{0} \Lambda _{c}^{+} \bar{\Lambda }_{c}^{-}) = [3.99 \pm 0.76({\mathrm{stat.}}) \pm 0.51({\mathrm{syst.}})] \times 10^{-4}$$ B(B¯0→K¯0Λc+Λ¯c-)=[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, $$Y_{\eta }$$ Yη , in the $$\Lambda _{c}^{+}\bar{\Lambda }_{c}^{-}$$ Λc+Λ¯c- invariant mass spectrum. No clear signals of the Y(4660) or $$Y_{\eta }$$ 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 $$(772\pm 11)\times 10^{6} B\bar{B}$$ (772±11)×106BB¯ pairs collected at the $$\Upsilon (4S)$$ Υ(4S) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.