Testing the Landau gauge operator product expansion on the lattice with a < A(2)> condensate - art. no. 114003

Using the operator product expansion we show that the O(1/p(2)) correction to the perturbative expressions for the gluon propagator and the strong cou pling constant resulting from lattice simulations in the Landau gauge are d ue to a nonvanishing vacuum expectation value of the operator A(mu)A(mu). T his is done using the recently published Wilson coefficients of the identit y operator computed to third order, and the subdominant Wilson coefficient computed in this paper to the leading logarithm. As a test of the applicabi lity of OPE we compare the [A(mu)A(mu)] estimated from the gluon propagator and the one from the coupling constant in the flavorless case. Both agree within the statistical uncertainty root [A(mu)A(mu)] similar or equal to 1. 64(15) GeV. Simultaneously we fit Lambda(MS) over bar = 233(28) MeV, in per fect agreement with previous lattice estimates. When the leading coefficien ts are only expanded to two loops, the two estimates of the condensate diff er drastically. As a consequence we insist that the OPE can be applied in p redicting physical quantities only if the Wilson coefficients are computed to a high enough perturbative order.