Study Of Charmonium Decay To γωΦat BESⅢ

QCD predicts a rich spectrum of gg glueball, qqg hybrids, and multiquark states along with ordinary qq meson in the1.0～2.5GeV mass region. Radiative J/ψ decays provide an excellent laboratory for probing these QCD predictions. Systems of two vector particles have been intensively studied for signatures of gluonic bound states. Pseudoscalar enhancements in ωω, ρρ and φφ final states have been seen in radiative J/ψ decays. Further studies are needed to understand the nature of these states.The radiative decay J/ψ�'γωφ is a doubly OZI suppressed process and its production ratio is expected to be suppressed by at least one order of magnitude. The measurement of this decay and the search for possible resonant states will provide useful information on two vector meson systems. In the year of2006, BES Ⅱ Collaboration have studied J/ψ�'γωφ decays and observed a signal with JPC=0++near threshold in the ωφ invariant mass spectrum.In this analysis, using the2.25×108J/ψ events collected by BESⅢ detector at BEPCⅡ, we study the decay J/ψ�'γωφ again. The enhancement near ωφ invariant mass spectrum is confirmed. A Partial Wave Analysis (PWA) with the tensor covariant amplitude shows that the structure is dominated by a0++state together with small contributions from2++and0-+. From the mass and width scan in the PWA, the mass of the scalar is1795±7-5+23MeV, the width is95±10-34+78MeV, and the branching fraction isB(J/ψ�'γX(1810))×B(X(1810)�'ωφ)=(1.99±0.08-0.99+1.37)×10-4These results are consistent with those of BESⅡ within errors.Decays of the XcJ(J=0,1,2) P-wave charmonium states are considered to be an ideal laboratory to test QCD theory. In the case of χcJ decays into pairs of vector VV, the branching fractions for χc0/2decays to φφ and ωω are much larger than the predictions based on perturbative QCD calculations. Besides, the decays of the χc1into VV violate the helicity selection rule (HSR) and are expected to be highly suppressed; V is vector ω,φ.Using the1.06×108ψ’ events collected by BESIII detector at BEPCII, we study the decay of ψ’�'γK+K-π+π-π0carefully. The decays χcJ�'ωφ are observed for the first time, where ω is reconstructed from π+π-π0and φ from K+K-. The branching fractions are B(χc0�'ωφ)=(1.23±0.15±0.14)×10-4B(χc1�'ωφ)=(2.17±0.54±0.26)×10-5At90%confidence level, the upper limit of χc2�'ωφ is: B(χc2�'ωφ)<2.3×10-5We also calculate the branching fractions of χcJ�'φφ, where one φ is recon-structed from π+π-π0and the other from K+K-. And the decay of χc1�'φφ is firstly observed. The branching fractions are B(χc0�'φφ)=(9.2±0.7±1.0)×10-4B(χc1�'φφ)=(5.0±0.5±0.6)×10-4B(χc2�'φφ)=(10.7±0.7±1.2)×10-4These results are consistent with those from final states with K+K-K+K-...