We obtain a new value for the QCD coupling constant by combining lattice QCD simulations with experimental data for hadron masses. Our lattice analysis is the first to: 1) include vacuum polarization effects from all three light-quark flavors (using MILC configurations); 2) include third-order terms in perturbation theory; 3) systematically estimate fourth and higher-order terms; 4) use an unambiguous lattice spacing; and 5) use an \order(a2)-accurate QCD action. We use 28~different (but related) short-distance quantities to obtain αMSˉ(5)(MZ)=0.1170(12).
@article{arxiv.hep-lat/0503005,
title = {Accurate Determinations of $\alpha_s$ from Realistic Lattice QCD},
author = {Q. Mason and H. D. Trottier and C. T. H. Davies and K. Foley and A. Gray and G. P. Lepage and M. Nobes and J. Shigemitsu},
journal= {arXiv preprint arXiv:hep-lat/0503005},
year = {2009}
}
Comments
4 pages, 2 figures, 1 table. The revised version differs from the original because we now use 4-loop beta functions (rather than 3-loop). This shifts the answer a little (mostly from the evolution from the lattice scale to M_z -- lattice results aren't very different) and reduces the error slightly