Partial Wave Analysis Of J/ψ->γπ~+π~-

Quantum Chromodynamics (QCD) is the fundamental theory describing the strong interactions. It predicted the existence of new forms of hadrons (glueballs, hybrids and multi-quark states), all of which are not yet experimentally established. At present, all established hadrons are composed of two or three quarks. As a result, the observation and study of new type hadrons have been the main concern of high energy physics experiments, providing significant importance to the verification and development of theories for strong interaction. BESⅢpays main concentration on the study of J/ψdecay and charmonium physics. And the radiative J/ψdecay is the perfect laboratory for new type hadrons finding. Based on this advantage, the main work of this paper is to utilize 220M J/ψdata sample taken from BESⅢto search for new type hadrons.The search of guleball has been the focus of physics, many excellent works have been done, suggesting the existence certain glueball candidates such as fo(1500) and fo(1710), but until now there is no firm conclusion.At the beginning, we discussed event selection and background study of decay channel J/ψ->γπ+π-, and then subtracted main backgroundρπusing reweighting method:selectingρπsignal from J/ψdata to get background by adjustments. The input/output check of this method is also included in this paper.Binned Maximum Likelihood fitting method is used in this paper to analyze the selectedγπ+π- events, and we did thorough research on the guleball candidates, especially around the mass of 1.5～1.7GeV/c2. The mass, width and statistical error information of each resonance is shown below:fo(1500):The statistical significance of fo(1500) is greater than 5σ, the measured mass is 1.4645±0.0026GeV/c2 and width is 0.1232±0.0049GeV/c2;fo(1710):The statistical significance of f0(1710) is greater than 5σ, the measured mass is 1.7660±0.0030GeV/c2 and width is 0.1687±0.0072GeV/c2, which are consistent with the result of BESⅡ;The fo(1500) and fo(1710) are the scalar glueball candidates, and theγππdecay mode of them can provide a great important approach to study their properties. More experimental results are needed to understand them.