  We consider several classes of analytic parametrizations of hadronic
scattering amplitudes, and compare their predictions to all available forward
data (proton- proton, antiproton-proton, pion-proton, kaon-proton,
photon-proton, photon- photon, sigma-proton). Although these parametrizations
are very close for energy larger than 9 GeV, it turns out that they differ
markedly at low energy, where a universal Pomeron term ~(ln s)**2 enables one
to extend the fit down to 4 GeV.

High Energy Physics - Phenomenology