Evidence of a structure in K�0?c+ consistent with a charged ? c(2930) + , and updated measurement of B�0?K�0?c+?�c- at Belle: Belle Collaboration

Abstract

We report evidence for the charged charmed-strange baryon ? c(2930) + with a signal significance of 3.9? with systematic errors included. The charged ? c(2930) + is found in its decay to KS0?c+ in the substructure of B�0?KS0?c+?�c- 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(B�0??c(2930)+?�c-)B(?c(2930)+?K�0?c+)=[2.37�0.51(stat.)�0.31(syst.)]�10-4. We also measure B(B�0?K�0?c+?�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?, in the ?c+?�c- invariant mass spectrum. No clear signals of the Y(4660) or Y? 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 6BB� pairs collected at the ? (4 S) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider. � 2018, The Author(s).