Toward the non-perturbative description of high energy processes

Abstract

General implications of the existence of non-perturbative scales smaller than 1 fm and the hadronic sub-structure for high energy processes are discussed. We propose that the observed dependence of the q ̄ q dipole cross section with nucleon σ( b, x) on the dipole size b is consistent with an instanton-based substructure. Then we use instanton dynamics to make the Kharzeev-Levin pomeron model [D. Kharzeev, E. Levin, BNL-NT-99-8, December 1999, hep-ph/9912216]. We fix the values for the gluon-to-hadron coupling constants including two scalar resonances: the σ (scalar ππ) and the scalar glueball G 0. These channels are special because the instanton-induced attractive interaction makes these hadrons unusually small in size, increasing their coupling constants. As the pomeron is a small-size object by itself, these resonances should have a a special role in its dynamics. We conclude that the non-perturbative part of the scalar contribution to the soft pomeron intercept is Δ=0.05±0.015, with comparable contributions from both σ and G 0.