αSfromΥspectroscopy with dynamical Wilson fermions

Abstract

We estimate the QCD coupling constant from a lattice calculation of the bottomonium spectrum. The second order perturbative expansion of the plaquette expectation value is employed to determine α S at a scale set by the

Light hadron spectrum and quark masses

“…Recent results of α Table 2. Recent values using the Wilson-type quark action for sea quarks [58,62] are significantly smaller compared to a standard lattice result previously obtained by Davies et al [61] using KS fermions. In particular this year's result of the QCDSF-UKQCD collaboration is smaller despite a consistent use of two-loop perturbation theory and a continuum extrapolation [59].…”

First results on the running coupling in QCD with two massless flavours

“…This in turn translates into errors of 2% and 5% for α in the range where its value is close to 0.12 corresponding to the physical value of α MS at M Z . 3…”

The unquenched ϒ spectrum

“…We use the standard method of determining α s from a perturbative expansion of the plaquette [1,7,8], setting the scale using the Υ 1P-1S splitting. This requires a calculation of the N f dependent part of the plaquette at O(α 2 s ) for clover fermions.…”