An estimate of αS from bottomonium in unquenched QCD

We estimate the strong coupling constant from the perturbative expansion of the plaquette. The scale is set by the 2S-1S and 1P-1S splittings in bottomonium which are computed in NRQCD on dynamical gauge configurations with nf = 2 degenerate Wilson quarks at intermediate masses. We have increased the statistics of our spectrum calculation in order to reliably extrapolate in the sea-quark mass. We find a value of αMS(mZ) = 0.1118(26) which is somewhat lower than previous estimates within NRQCD.