2025/12/10 by Mena-Valle, Jose M.
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2512.09888
The strong coupling αs is extracted with high precision through fits to lattice-QCD data for the static energy. Our theoretical framework is based on R-improving the three-loop fixed-order prediction for the static energy: we remove the u=1/2 renormalon and resum the associated large infrared logarithms. Combined with radius-dependent renormalization scales (the so-called profile functions), this procedure extends the range of validity of perturbation theory to distances as large as ∼ 0.5 fm. In addition, we resum large ultrasoft logarithms to N3LL accuracy using renormalization-group evolution. Since the standard four-loop R-evolution treats N4LL and higher-order contributions asymmetrically, we also incorporate this potential source of bias in our analysis. Our estimate of the perturbative uncertainty is obtained through a random scan over the parameters controlling the profile functions and the implementation of R-evolution. We analyze how the extracted value of αs depends on the shortest and longest distances included in the fit, on the details of the R-evolution procedure, on the fitting strategy itself, and on the accuracy of ultrasoft resummation. From our final analysis, and after evolution to the Z pole, we obtain α(nf=5)s(mZ)=0.1170± 0.0009, a result fully compatible with the world average and with a comparable uncertainty.