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=2 and 0ππ←→ρρ and I=0 ππ←→ωω reactions are calculated with the prior and post forms. 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.