Further Precise Determinations of $\hat{I}{\pm }_s$ from Lattice QCD

Abstract

We present a new determination of the strong coupling constant from lattice QCD simulations. We use four different short-distance quantities to obtain the coupling, three different (infrared) meson splittings to tune the simulation parameters, and a wide range of lattice spacings, quark masses, and lattice volumes to test for systematic errors. Our final result consists of ten different determinations of $\hat{I}{\pm }_P^{(3)}(8.2GeV)$, which agree well with each other and with our previous results. The most accurate of these, when evolved perturbatively to the $Z^0$ mass, gives $α^{(5)}_{\msbar}(M_Z) = .1174(24)$. We compare our results with those obtained from other recent lattice simulations.

24 pages, LaTeX