Transparent expression of the A2 condensate's renormalization

Abstract

We give a more transparent understanding of the vacuum expectation value of the renormalized local operator A2 by relating it to the gluon propagator integrated over the momentum. The quadratically divergent perturbative contribution is subtracted and the remainder, dominantly due to the O(1/p2) correction to the perturbative propagator at large p2 is logarithmically divergent. This provides a transparent derivation of the fact that this O(1/p2) term is related to the vacuum expectation value of the local A2 operator and confirms a previous claim based on the operator product expansion (OPE) of the gluon propagator. At leading logarithms the agreement is quantitative, with a standard running factor, between the local A2 condensate renormalized as described above and the one renormalized in the OPE context. This result supports the claim that the BRST invariant Landau-gauge A2 condensate might play an important role in describing the QCD vacuum.