One-loop RG improvement of the screened massive expansion in the Landau gauge

Screened massive expansion of the quark propagator in the Landau gauge

“…[14], provided that the energy units of the screened 2 For a lengthy discussion on the conceptual similarities between the gluon mass parameter m 2 and the QCD scale Λ QCD see Ref. [57], where the issue was addressed in the context of the renormalization group improvement of the screened expansion. expansion are set by choosing m = 0.6557 GeV (see Fig.…”

“…Its renormalization in the Landau gauge was discussed in Refs. [56,57], where different renormalization schemes were considered and analytical expressions were reported for its beta function. The method has proven to be self-consistent and predictive when optimized by principles of gauge invariance [54,57].…”

“…While in principle the failure of ordinary PT to describe the gluon's infrared mass could be attributed to its break down at low energies, in recent years a new approach to the perturbation theory of pure Yang-Mills (YM) theory has shown that most of the nonperturbative content of the gluon dynamic -at least as far as the two-point functions are concerned -can be absorbed into a shift of the expansion point of the Yang-Mills perturbative series. This approach, termed the screened massive expansion [47][48][49][50][51][52][53][54][55][56][57][58], is a simple extension of ordinary PT, formulated in such a way as to treat the transverse gluons as massive already at tree level while leaving the total action of the theory unchanged. The screened expansion has proven to be self-consistent to one loop -since it is renormalizable and leads to an infraredfinite and moderately small running coupling constant [57] -and predictive when optimized by principles of gauge invariance [54]; it yields two-point functions which are in excellent agreement with the lattice data in the Landau gauge [54,57].…”

“…This approach, termed the screened massive expansion [47][48][49][50][51][52][53][54][55][56][57][58], is a simple extension of ordinary PT, formulated in such a way as to treat the transverse gluons as massive already at tree level while leaving the total action of the theory unchanged. The screened expansion has proven to be self-consistent to one loop -since it is renormalizable and leads to an infraredfinite and moderately small running coupling constant [57] -and predictive when optimized by principles of gauge invariance [54]; it yields two-point functions which are in excellent agreement with the lattice data in the Landau gauge [54,57].…”

Thermal extension of the screened massive expansion in the Landau gauge

“…In the last years, a very predictive analytical method has been developed [18][19][20][21] by a mere change of the expansion point of ordinary perturbation theory (PT) for the exact gauge-fixed Becchi-Rouet-Stora-Tyutin (BRST) invariant YM Lagrangian, yielding a screened massive expansion which is safe in the IR while recovering the correct results of ordinary PT in the UV. At oneloop and zero temperature, the screened expansion provides analytical results which are in excellent agreement with the lattice and can be easily continued to Minkowski space [21][22][23][24][25]. Thus the method provides a way to extract dynamical details like masses and damping rates from first principles.…”