A study of J/ψ→γγV(ρ,φ) decays with the BESII detector

Abstract Using a sample of 58×10 6 J / ψ events collected with the BESII detector, radiative decays J / ψ → γγV , where V = ρ or φ , are studied. A resonance around 1420 MeV/ c 2 ( X (1424)) is observed in the γρ mass spectrum. Its mass and width are measured to be 1424±10(stat)±11(sys) MeV/ c 2 and 101.0±8.8±8.8 MeV/ c 2 , respectively, and its branching ratio B ( J / ψ → γX (1424)→ γγρ ) is determined to be (1.07±0.17±0.11)×10 −4 . A search for X (1424)→ γφ yields a 95% C.L. upper limit B ( J / ψ → γX (1424)→ γγφ ) −4 .