The Partial Wave Analysis For J/ψ→γγρ

η(1405) is the first candidate of 0?? glueball. It is considered thatη(1405) may be consisted of multi resonances because of its wide width. There is a- lways a widely international concern over the study of the structure inη( 1405) mass range, it s important to analysis the ?? invariant mass spectra for resolving the structure of ? ?1 405?. Beside, we don t make sure that the quantum number of the resonance around 1276 MeV /c 2 in ?? invariant mass is 0? or 1? . So the thesis is aimed at analyzing the component of the resonance around 1440 MeV /c 2 and 1276 MeV /c 2 in ?? invariant mass.Covariant tensor amplitude partial wave analysis makes use of the particles experimental 4 momentum and the theoretical amplitudes, fitting the exper- imental data with the maximum likelihood method, comparing the results with the one experimental amplitude anticipates, determining the main resonances , the unknown parameters in the amplitudes of these processes(such as mass, width, plural coupling parameters et al.), branch ratios, spins, and the parities. Comparing the general method which fits the measure resonant parameters of the section and the branch ratios, partial wave analysis gives the full expression at amplitude level, which applies the energy, angle variables of the final state particles to form amplitudes, therefore, it takes fully account the contr- ibution of the interference effects, making the best of experimental data information, making the results more reliable.Based on 58 million J /ψevents collected with BESII detector, we analyze the J /ψ→γγρprocess with covariant tensor amplitude partial wave analysis. Firstly, we analyze the process J /ψ→γγρevents character and the backg- round, selecting the data sample by considering the analysis results and the detector s performance; secondly, form the likelihood function ? ln? with the 4 momentum of the data sample and the theoretical amplitude formalism of the resonances we add, gaining the fitting parameters by using Fumili program to minimize the ? ln?; finally calculate the theoretical resonant distribution with the parameters , mass, width of the resonance which gets from the second step, and MC sample, comparing the result with the data sample.With the serious partial wave analysis, we obtain ?? invariant mass, angle distribution fitting pictures, which show that our fitting results are re- asonable. Meanwhile, we can get ? ?1 405? branch ratio 6.17×10^-5, ? ?f1 1285 branch ratio 4.22×10^-5, ? ?f1 1420 branch ratio 5.12×10^-5 and ? ?1 295? branch ratio 4.23×10^-5. Comparing the ratios of ? ?f1 1285 and ? ?1 295?, we cannot draw a definite conclusion on whether the resonance whose invariant mass is around 1276 MeV /c 2 is 0? or 1? . We also have to analyze the J /ψ→γγρprocess to determine the structure of ? ?1 405?. Because the data statistical number is too small and the resonances we consider are not enough, further study is needed to clarify the situation.