Analytic Model of a Regge Trajectory in the Space-like and Time-like Regions

Abstract

A model for a Regge trajectory compatible with the threshold behavior required by unitarity and asymptotics in agreement with Mandelstam analyticity is analyzed and confronted with the experimental data on the spectrum of the $\rho$ trajectory as well as those on the ${\pi }^{-}p\to {\pi }^{0}n$ charge-exchange reaction. The fitted trajectory deviates considerably from a linear one both in the space-like and time-like regions, matching nicely between the two.

Comments: 6 pages, LaTeX, 4 eps figure, uses epsf.sty; presented at the Bogolyubov Conference, Moskow-Dubna-Kiev, 27 Sept.-6 Oct., 1999