Effects of off-mass-shell continuation in the multiperipheral model

The predictions of the Amati-Bertocchi-Fubini-Stanghellini-Tonin multiperipheral model concerning Regge trajectories and residues are presented for a number of different parametrizations of the off-shell ππ scattering amplitude. The unmodified model, in which the kernel is taken to be the on-shell amplitude, gives unsatisfactory results. The most natural continuation appears to involve the phenomenological form factors of D\"urr and Pilkuhn (DP). The use of the DP form factors leads to trajectories with slope about 1 GeV⁻² and intercepts ${\alpha }_{I=0}=0.57$ and ${\alpha }_{I=1}=0.36$. When K- and η-meson exchanges are included in the model, the DP form factors provide a sensible way of including bound-state vertices such as ρ KK̄ and K*Kη. The trajectory intercepts are now increased to ${\alpha }_{I=0}=0.63$ and ${\alpha }_{I=1}=0.42$, and the average multiplicities of the various secondaries are of the form clns, where $c_{\pi }=0.84$, $c_K=0.11$, and $c_{\eta }\approx {10}^{-4}$. It seems possible that this model, in conjunction with the "schizophrenic-Pomeranchon" mechanism, can provide a good description of high-energy processes.