On the zero crossing of the three-gluon vertex

TL;DR

This paper investigates the infrared behavior of the three-gluon vertex in quenched QCD, revealing a zero crossing linked to ghost masslessness, through lattice simulations and Schwinger-Dyson equations analysis.

Contribution

It provides new lattice simulation results showing the zero crossing of the three-gluon vertex and discusses its theoretical origin within Schwinger-Dyson equations.

Findings

Zero crossing observed in one kinematic configuration.

Effective coupling vanishes at the zero crossing.

Infrared feature linked to ghost masslessness.

Abstract

We report on new results on the infrared behaviour of the three-gluon vertex in quenched Quantum Chormodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as 'zero crossing', the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev-Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger-Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.