Universal slope and the nonlinear Regge trajectories

We have investigated constraints imposed by duality on the slopes of nonlinear trajectories. In Argand-loop analysis for square-root-type trajectories we show analytically that the leading and daughter trajectories in the s channel have the same form, except for an additive constant, as the input trajectory in the t channel. This result is also true for all leading nonlinear trajectories in a model proposal by Cohen-Tannoudji, Henyey, Kane, and Zakrzewski.