A peaking structure in the J/ψφ mass spectrum near threshold is observed in B ± → J/ψφK ± decays, produced in pp collisions at √ s = 7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/ψ, corresponds to an integrated luminosity of 5.2 fb −1 . Fitting the structure to an S-wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m = 4148.0 ± 2.4 (stat.) ± 6.3 (syst.) MeV and Γ = 28 +15 −11 (stat.) ± 19 (syst.) MeV, respectively. Evidence for an additional peaking structure at higher J/ψφ mass is also reported.Events are chosen using a two-level trigger system. The first level, composed of custom hardware processors, uses information from the muon detectors to select dimuon candidates. The high-level trigger (HLT) runs a special version of the offline software code on a processor farm to select events with nonprompt J/ψ candidates coming from the decays of B mesons.Events containing J/ψ candidates are selected by the HLT dimuon trigger. Because of the increasing LHC instantaneous luminosity, there are two configurations of the HLT, corresponding to two running periods and two distinct data sets. For both data sets, the following require-
B The CMS Collaboration
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.