Nonperturbative study of the three- and four-gluon vertices from lattice QCD

Abstract

In this work, we have focused our attention on the study of the gluon vertices of QCD. These vertices represent a key distinction between QCD and other theories, such as QED, where self-interactions among gauge bosons do not occur. This crucial difference gives rise to a wide range of unique phenomena, whose study requires an accurate understanding of the fundamental QCD vertices.

In this thesis (and the related works published during its completion), we present an in-depth study of the three- and four-gluon vertices of QCD, evaluated on the lattice through extensive quenched simulations in Landau gauge. For the first time, we extend the lattice study of the three-gluon vertex beyond symmetric and soft-gluon kinematics. Similarly, we perform the first lattice analysis of the four-gluon vertex beyond restricted kinematics and provide the first lattice determination of the running coupling extracted from the four-gluon vertex. Finally, we explore some phenomenological applications of the three- and four-gluon vertices.