Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
; Univ Sci & Technol China, Dept Modern Phys, Hefei 230026, Peoples R China
It is an ideal place to search for exotic states through J/psi hadronic decays. In this paper, we discuss the way to use the partial wave analysis (PWA) based on covariant helicity amplitude analysis to study the invariant mass spectrum of etapi and to find the evidence of the existence of exotic states in this channel. The formula for PWA is also given. It is the theoretical foundation of experimental physics analysis on exotic states searching in J/psi hadronic decays. The theoretical formula can also be used in physics analysis of J/psi decays into omegapipi, phipipi, omegaKK, phiKK and K* (892)Kpi.