The relation between reggeon and photon couplings

Abstract

We propose (a) the “vector coupling hypothesis” (VCH) that the leading normal-parity Regge trajectories (P, f, ω, ϱ and A 2) couple to hadrons like vector particles, and (b) the “γ-analogy hypothesis” (GAH), that the couplings of P, f, and ω to any vertex are proportional to the isoscalar photon coupling (the transition form factor), while ϱ and A 2 couple like the isovector photon. These hypotheses are motivated by duality and vector dominance. They allow us to interconnect such well-known results as (a) the relation between s-channel helicity conservation for P, f and ω at the N N vertex and the equality of the nucleon's electric and magnetic isoscalar form factors, (c) the Stodolsky-Sakurai flip ϱ and A 2 couplings to N N and the isovector form factors, (c) the Stodolsky-Sakurai magnetic dipole ϱ-N Δ coupling. They also permit us to predict, with just a single free parameter, the differential cross section for pp → pN ∗ , at all energies, in terms of that for pp → pp. A detailed method for relating the transition form factors to the reggeon couplings for any spin is presented.