Hadronic scattering amplitudes: medium-energy constraints on asymptotic behaviour

Abstract

We consider several classes of analytic parametrisations of hadronic scattering amplitudes, and compare their predictions to all available forward data (p p, pbar p, pi p, K p, gamma p, gamma gamma, Sigma p). Although these parametrisations are very close for sqrt(s) > 9 GeV, it turns out that they differ markedly at low energy, where a universal pomeron term ~log^2(s) enables one to extend the fit down to sqrt(s)=4 GeV.

Comments: 33 pages. Notations revised, clarified and corrected, appendix added with the formulae used, one reference added, typos corrected