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J/ψ and ψ ′ decay to mesons are a good place to look for glueballs, hybrids and for extracting strange and nonstrange components in mesons. Abundant J/ψ and ψ ′ events have been collected at the Beijing Electron Positron Collider (BEPC). More data will be collected at upgraded BEPC and CLEO-C. Here we provide explicit PWA formulae for many interesting channels in the covariant tensor formalism.

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With t-channel p and f2(1275) exchange and the s-channel resonance fo(975), we reproduce the aa Swave scattering phase shift up to 1.1 GeV quite well. A broad pole ~( 4 0 0 )is produced by the t-channel p exchange. The f0(975) has a large decay width due to its broad third-sheet pole and a narrow peak width due to its narrow second-sheet pole.