Ghost dynamics in the soft gluon limit

TL;DR

This paper investigates the ghost sector dynamics in quenched QCD within the Landau gauge by solving coupled Schwinger-Dyson equations, using lattice data to achieve results that align well with numerical and theoretical expectations.

Contribution

It provides a comprehensive numerical solution of the ghost and ghost-gluon vertex equations in the soft gluon limit, integrating lattice data to validate the approach.

Findings

Excellent agreement with lattice data for the ghost dressing function

Confirmation of the ghost-gluon vertex's behavior in the soft gluon limit

Demonstration of the consistency between different computational schemes

Abstract

We present a detailed study of the dynamics associated with the ghost sector of quenched QCD in the Landau gauge, where the relevant dynamical equations are supplemented with key inputs originating from large-volume lattice simulations. In particular, we solve the coupled system of Schwinger-Dyson equations that governs the evolution of the ghost dressing function and the ghost-gluon vertex, using as input for the gluon propagator lattice data that have been cured from volume and discretization artifacts. In addition, we explore the soft gluon limit of the same system, employing recent lattice data for the three-gluon vertex that enters in one of the diagrams defining the Schwinger-Dyson equation of the ghost-gluon vertex. The results obtained from the numerical treatment of these equations are in excellent agreement with lattice data for the ghost dressing function, once the latter have undergone the appropriate scale-setting and artifact elimination refinements. Moreover, the coincidence observed between the ghost-gluon vertex in general kinematics and in the soft gluon limit reveals an outstanding consistency of physical concepts and computational schemes.