Abstract
The RG improvement of the screened massive expansion is studied at one loop in two renormalization schemes, the momentum subtraction (MOM) scheme and the screened momentum subtraction (SMOM) scheme. The respective Taylor-scheme running couplings are shown not to develop a Landau pole, provided that the initial value of the coupling is sufficiently small. The improved ghost and gluon propagators are found to behave as expected, displaying dynamical mass generation for the gluons and the standard UV limit of ordinary perturbation theory. In the MOM scheme, when optimized by a matching with the fixed-coupling framework, the approach proves to be a powerful method for obtaining propagators which are in excellent agreement with the lattice data already at one loop. After optimization, the gluon mass parameter is left as the only free parameter of the theory and is shown to play the same role of the ordinary perturbative QCD scale $\Lambda_{\text{QCD}}$.
Highlights
Being able to describe the nonperturbative regime of QCD is of paramount importance for understanding the low-energy phenomenology of hadrons, for predicting the observed hadron-mass spectrum and for addressing many unsolved problems like confinement, chiral symmetry breaking, and dynamical mass generation [1,2,3,4,5,6,7]
In this paper we show how the problem can be solved by the renormalization group (RG), yielding an improved screened expansion whose validity can be virtually extended to any energy scale
The RG-improved screened expansion is studied at one loop for the puregauge YM theory in two different renormalization schemes and is shown to be under control down to arbitrarily small scales, even if higher-order terms become important in the IR, where the one-loop RG-improved results get worse than the optimized fixed-coupling expressions
Summary
Being able to describe the nonperturbative regime of QCD is of paramount importance for understanding the low-energy phenomenology of hadrons, for predicting the observed hadron-mass spectrum and for addressing many unsolved problems like confinement, chiral symmetry breaking, and dynamical mass generation [1,2,3,4,5,6,7]. In the IR and as far as the two-point functions are concerned, the higher-order terms of the perturbative series were shown to be minimized by an optimal choice of the renormalization scheme [55,58,59], yielding a very predictive analytical tool and one-loop results that are in excellent agreement with the available lattice data for YM theory. The RG-improved screened expansion is studied at one loop for the puregauge YM theory in two different renormalization schemes and is shown to be under control down to arbitrarily small scales, even if higher-order terms become important in the IR, where the one-loop RG-improved results get worse than the optimized fixed-coupling expressions.
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