Alpha_s(M_Z) from hadronic tau decays
  We perform an extraction of alpha_s based on sum rules involving isovector hadronic tau decay data. The particular sum rules employed are constructed specifically to suppress contributions associated with poorly known higher dimension condensates, and hence reduce theoretical systematic uncertainties associated with the treatment of such contributions which are shown to be present in earlier related analyses. Running our results from the n_f=3 to n_f=5 regime we find alpha_s(M_Z^2)=0.1187(16), in excellent agreement with the recently updated global fit to electroweak data at the Z scale, 0.1191(27), and other high-scale direct determinations. 
K. Maltman and T. Yavin