Nonzero Mean Squared Momentum of Quarks in the Non-Perturbative QCD Vacuum

TL;DR

This paper investigates the nonzero mean squared momentum (virtuality) of quarks in the non-perturbative QCD vacuum by solving Dyson-Schwinger Equations, providing numerical predictions that differ from other models.

Contribution

It introduces a method to calculate quark virtuality using Dyson-Schwinger Equations and compares results with existing theoretical models.

Findings

Calculated quark virtuality values differ from QCD sum rules.

Numerical results show discrepancies with Lattice QCD and instanton models.

Provides new insights into quark behavior in the QCD vacuum.

Abstract

The non-local vacuum condensates of QCD describe the distributions of quarks and gluons in the non-perturbative QCD vacuum. Physically, this means that vacuum quarks and gluons have nonzero mean-squared momentum, called virtuality. In this paper we study the quark virtuality which is given by the ratio of the local quark-gluon mixed vacuum condensate to the quark local vacuum condensate. The two vacuum condensates are obtained by solving Dyson-Schwinger Equations of a fully dressed quark propagator with an effective gluon propagator. Using our calculated condensates, we obtain the virtuality of quarks in the QCD vacuum state. Our numerical predictions differ from the other theoretical model calculations such as QCD sum rules, Lattice QCD and instanton models.