Study Of J/ψâ†'X+4(Ï€+Ï€-)â†'and ψ′â†'(?)+c.c Decay

Recently there have been few people studying on the resonant state which has great amounts of the charged particle multiplicities, in instance the resonant state, which decays to the eight charged particle tracks, has not been measured in the experiment. In order to search for this new decay process, we studied and analyzed final states including eight charged tracks on the decay process J/ψâ†'X+4(Ï€+Ï€-) systematically. For J/ψâ†'γ+4(Ï€+Ï€-) decay process, we observed a new decay modes ηcâ†'4(Ï€+Ï€-) for the first time. Before that, there was no experimental results measured in the decay process J/ψâ†'γ+4(Ï€+Ï€-) and J/ψâ†'4(Ï€+Ï€-), also their branching ratios were not presented. In this paper, we first measured those two decays modes of J/ψ. Concerning the measurement of the branching ratio of J/ψâ†'Ï€04(Ï€+Ï€-) in the PDG is obsolete, whose result introduced about30%measurement error. We restudied this decay process and measured its branching ratio in the paper.Besides, the decay process ψ’â†'∧(?)0+c.c is isospin-violated decay, which is caused by one-photon-exchange mechanism. The level of isospin-violation can also help us understand the other SU(3) breaking mechanism. Therefore, we use data collected on the BESIII to analyze and measure the branching ratio correlated to the decay. In addition, studying the process of y,ψ’â†'γ∧(?) can also help us search for the decay processes with the resonances which include∧(?) final states.