Covariant Helicity Amplitude Analysis for J/ψ→γPP

Covariant helicity amplitude analysis for the process of J/ψ →γPP is discussed.Starting from the S- matrix elements of decay process,we deduce the formulae of helicity coupling amplitudes for two-body decay process. These formulae are used to analyze intermediate resonance states in the process of J/ψ decay to γππ,γKK,γηη＇ etc.