Cross sections for ππ↔ρρ and ππ↔ωω reactions

To study chemical equilibrium of hadronic matter created in relativistic heavy ion collisions, phase shifts for the I=2ππ elastic scattering and cross sections for the I=2and0ππ↔ρρ and I=0ππ↔ωω reactions are calculated with the prior and post forsm. While the post-prior equivalence holds for the elastic scattering, the post-prior discrepancy of the inelastic scatterings relies on the spin-dependent terms of quark-antiquark potential. (authors)