Singular gauge potentials and the gluon condensate at zero temperature

We consider a new cooling procedure which separates gluon degrees of freedom froth singular center vortices in SU(2) LGT in a gauge invariant way. Restricted by a cooling scale kappa(4)/sigma(2) fixing the residual SO(3) gluonic action relative to the string tension, the procedure is RG invariant. In the limit kappa --> 0 a pure Z(2) vortex texture is left. This minimal vortex content does not contribute to the string tension. It reproduces, however, the lowest glueball states. With an action density scaling like a(4) with beta, it defines a finite contribution to the action density at T = 0 in the continuum limit. We propose to interpret this a mass dimension 4 condensate related to the gluon condensate. Similarly, this vortex texture is revealed in the Landau gauge.