The Running Coupling From Lattice QCD

Abstract

A recent lattice calculation of the QCD running coupling is presented. The coupling is extracted from the force between two static quarks in the framework of the valence quark approximation. A value of the Lambda-parameter for zero quark flavours is determined: Lambda_msbar=0.630(38)\sqrt{\sigma} =293(18)^{+25}_{-63} MeV. The first error is statistical, the second stems from the overall scale uncertainty in the string tension sigma. Combining this value with results from full QCD lattice simulations, we end up with the estimate $\Lambda^{(4)}_{\overline{MS}}=129(8)^{+43}_{-60}$~MeV or $\alpha_{\overline{MS}}(m_Z)=0.102^{+06}_{-11}$.