Nonperturbative contribution to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi and Gribov-Levin-Ryskin equation

TL;DR

This paper investigates the nonperturbative effects on QCD evolution equations, showing how they suppress evolution at low Q^2 and reduce shadowing, enabling a smooth transition from soft to hard scattering regimes.

Contribution

It introduces a method to incorporate nonperturbative contributions into evolution equations, clarifying their impact on low Q^2 and small-x physics.

Findings

Nonperturbative effects suppress evolution at low Q^2 and small-x.

Nonperturbative contributions weaken shadowing effects.

A smooth transition from soft to hard QCD regimes is proposed.

Abstract

By studying the nonperturbative contribution to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi and Gribov-Levin-Ryskin equation, it is found that (i) the nonperturbative contribution suppresses the evolution rate at the low $Q^2$, small-x region; (ii) the nonperturbative contribution weakens the shadowing effect. The method in this paper suggests a smooth transition from the low $Q^2$ ("soft"), where nonperturbative contribution dominates, to the large $Q^2$ ("hard") region, where the perturbative contribution dominates and the nonperturbative contribution can be neglected. PACS numbers:12.38.Aw, 13.60.Hb