Lambda^2-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 $\Lambda^2$, 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 $\Lambda^2$-contribution could be present coming from the large momentum behaviour of the running coupling and not connected to operator product expansion.