We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, Υ{hooked}, and Drell-Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8±3.2)% of the bb̄ production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9±0.4)% for events due to bb̄ production. © 2011 The Author(s).

The observation of the Y (4140) structure in B± → J/ΨφK± decays produced in pp collisions at √ s = 1.96 TeV is reported with a statistical significance greater than 5 standard deviations. A fit to the J/Ψφ mass spectrum is performed assuming the presence of a Breit-Wigner resonance. The fit yields a signal of 19 ± 6 (stat) ± 3 (syst) resonance events, and resonance mass and width of 4143.4+2.9 -3.0 (stat)±0.6 (syst) MeV/c2 and 15.3+10.4 -6.1 (stat)±2.5 (syst) MeV/c2, respectively. The parameters of this resonancelike structure are consistent with values reported from an earlier CDF analysis.