Pion-nucleon charge-exchange scattering and the crossover phenomenon with M=0 ρ and M=1 ρ' trajectories

Abstract

A Regge-pole model with (M=0) ρ and (M=1) ρ' trajectories is used to fit the πN charge-exchange differential cross-section and polarization data. The model automatically predicts the crossover phenomenon around t=-0.2 GeV² in πN elastic scattering without assuming any zeros in the nonflip ρ residue. Thus it avoids difficulties of such zeros due to factorization. The parameters of the ρ and ρ' are consistent with the nucleon electromagnetic form factors and predict the mass of ρ' to be around 1.1 GeV.