A model for pion-pion scattering in large-N QCD

Understand

Following up on recent work by Caron-Huot et al.

• we consider a generalization of the old Lovelace-Shapiro model as a toy model for Pi-Pi scattering satisfying (most of) the properties expected to hold in ('t Hooft's) large-N limit of massless QCD.
• In particular, the model has asymptotically linear and parallel Regge trajectories at positive t, a positive leading Regge intercept $\alpha_0 < 1$, and an effective bending of the trajectories in the negative-t region producing a fixed branch point at J=0 for $t < t_0 < 0$.
• Fixed (physical) angle scattering can be tuned to match the power-like (including logarithmic corrections) behavior predicted by perturbative QCD: $A(s,t) ~ s^{-\beta} \log(s)^{-\gamma} F(\theta)$.