G. Burgio

Λ2-contribution to the condensate in lattice gauge theory

Abstract We present some evidence that in lattice gauge theory the condensate contains a non-perturbative contribution proportional to Λ2, the square of the physical scale. This result is based on an analysis of the Wilson loop plaquette expectation from Monte Carlo simulations and its perturbative expansion computed to eight loops. The analysis is not fully conclusive since the calculations are done on a finite lattice and one needs an extrapolation to infinite lattice. It has been recently suggested that in the gluon condensate a Λ2-contribution could be present coming from the large momentum behaviour of the running coupling and not connected to operator product expansion.We present some evidence that in Lattice Gauge Theory the condensate contains a non-perturbative contribution proportional to

Lattice calculation of 1 / p**2 corrections to alpha(s) and of Lambda(QCD) in the MOM scheme

\Lambda^2

Lattice calculation of

, the square of the physical scale. This result is based on an analysis of the Wilson loop plaquette expectation from Monte Carlo simulations and its perturbative expansion computed to eight loops. The analysis is not fully conclusive since the calculations are done on a finite lattice and one needs an extrapolation to infinite lattice. It has been recently suggested that in the gluon condensate a

1/p^2

\Lambda^2

corrections to

-contribution could be present coming from the large momentum behaviour of the running coupling and not connected to operator product expansion.

\alpha_s

We report on very strong evidence of the occurrence of power terms in

and of

\as(p)

\Lambda_{\rm {QCD}}

, the QCD running coupling constant in the

in the

\widetilde{MOM}

\widetilde{MOM}

scheme, by analyzing non-perturbative measurements from the lattice three-gluon vertex between 2.0 and 10.0 GeV at zero flavor. While putting forward the caveat that this definition of the coupling is a gauge dependent one, the general relevance of such an occurrence is discussed. We fit