2020/12/31 by LHCb collaboration, R. Aaij, C. Abellán Beteta +959 · 5 citations
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1016/j.scib.2021.02.030
published as Sci.Bull. 66 (2021) 1278-1287 · All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-039.html (LHCb public pages)
arxiv created 2021/07/04 · arxiv updated 2021/07/06
First evidence of a structure in the J/ψ\varLambda invariant mass distribution is obtained from an amplitude analysis of \varXib- → J/ψ\varLambda K- decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness. Its mass and width are determined to be 4458.8±2.9 +4.7-1.1MeV and 17.3±6.5 +8.0-5.7MeV, where the quoted uncertainties are statistical and systematic, respectively. The structure is also consistent with being due to two resonances. In addition, the narrow excited \varXi- states, \varXi(1690)- and \varXi(1820)-, are seen for the first time in a \varXib- decay, and their masses and widths are measured with improved precision. The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9fb-1, collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV.