Gluonic Structure of the Constituent Quark

TL;DR

This paper investigates the gluon content of the constituent quark and nucleon using the instanton model of QCD vacuum, revealing the significant role of pion fields and proposing insights into the proton spin problem.

Contribution

It introduces a combined approach using the constituent quark model and instanton effects to calculate gluon distributions, including both perturbative and non-perturbative interactions.

Findings

Gluon distributions are significantly influenced by instanton-induced non-perturbative effects.

Pion fields play a crucial role in shaping gluon distributions in hadrons.

The approach offers potential insights into the proton spin problem.

Abstract

Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.