Implications of Unequal-Mass Kinematics for the Regge-Pole Model of Vector-Meson Production

Application of the Regge-pole model to vector-meson production by incident pseudoscalars is reexamined in the light of recent theoretical advances in the treatment of unequal-mass processes. It is found that in the absence of conspiracy between trajectories at $t=0$, the kinematic factors separated from the helicity amplitudes before Reggeization tend to suppress the effects of parity = (-1)J exchanges relative to parity = (-1)J+1 contributions, in the region |t|≤0.2 GeV². This helps account for the experimental observation that, although α_π is less than αA2,α_ω⋯, π exchange tends to dominate the forward peak wherever it is possible (production of ρ and K* mesons). This kinematic suppression also helps explain the failure of ρ exchange to dominate in ω production.