On the zero-crossing of the three-gluon Green’s function from lattice simulations

Abstract

Abstract. We report on some efforts recently made in order to gain a better understanding of some IR properties of the 3-point gluon Green's function by exploiting results from large-volume quenched lattice simulations. These lattice results have been obtained by using both tree-level Symanzik and the standard Wilson action, in the aim of assessing the possible impact of effects presumably resulting from a particular choice for the discretization of the action. The main resulting feature is the existence of a negative logaritmic divergence at zero-momentum, which pulls the 3-gluon form factors down at low momenta and, consequently, yields a zero-crossing at a given deep IR momentum. The results can be correctly explained by analyzing the relevant Dyson-Schwinger equations and appropriate truncation schemes.

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Instanton dominance over αs at low momenta from lattice QCD simulations at Nf = 0, Nf = 2 + 1 and Nf = 2 + 1 + 1

“…For the quenched data, we considered the large volume simulations employed in [8,9] for a very detailed study of the deep IR running of gluon Green functions, while for the unquenched case we will use two sets of lattice data. The first includes N f = 2 + 1 field configurations produced by the RBC/UKQCD collaboration using domain wall fermions close to the physical pion mass [10] and three different values of β.…”

Reconstructing QCD Spectral Functions with Gaussian Processes

“…In the past two decades, increasing interest in the momentum behavior of the fundamental two-point Green's functions in QCD as well as further correlation functions of higher order has triggered respective lattice calculations in particular of Yang-Mills and QCD propagators; see e.g. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. The lattice data for the ghost dressing function and gluon propagator employed in this work, shown in Figure 1, are obtained from recent simulations of 2+1 flavor QCD at the physical point [4,5]; see Appendix B 1 for further details and references.…”