Stefan Sint (for the ALPHA collaboration)
On the accuracy of perturbation theory in QCD
A collaborative effort to determine the strong coupling αs(mZ) from low energy hadronic input (such as the pion and kaon masses or life times) is nearing completion. The only method able to systematically address this problem is lattice QCD and the main challenge then consists in the resolution of the large scale differences involved. I will explain the overall strategy and then focus on the running of the coupling at high energies where we can confront non-perturbative continuum extrapolated data with renormalized perturbation theory. The available scales cover 2 orders of magnitude, so that we can assess the attainable accuracy of perturbation theory in QCD.