Observation of a peaking structure in the J/ψφmass spectrum from B±→J/ψφK±decays

Article history: Received 26 September 2013 Received in revised form 11 April 2014 Accepted 7 May 2014 Available online 22 May 2014 Editor: M. Doser 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. © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). Funded by SCOAP3.