Observation of the Y (4140) structure in the J/ψϕ mass spectrum in B±→ J/ψϕK± decays

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 4143.4−3.0+2.9(stat) ± 0.6(syst)MeV/c2 and 15.3−6.1+10.4(stat) ± 2.5(syst)MeV/c2, respectively. The parameters of this resonance-like structure are consistent with values reported from an earlier CDF analysis.