00 2 Minimum Of QCD Effective Action As Test Of QCD Confinement Parameter

Recently (hep-ph/0109278), a modification A µ → B µ = (1 + µ∂ m)A µ for the gluon field A µ in the QCD Lagrangian (m = small gluon mass), yielded a k −4 behaviour for the gluon propagator, conventionally associated with linear confinement. This was prompted by a lack of consensus of results from other standard non-perturbative approaches on the T-dependence of gluon condensates in the cos-mological context. Indeed, the gluon and quark condensates, and the pionic f π , were all reproduced with a value of µ = 1GeV .We now provide a basis to the confinement scale parameter µ by finding its formal relation to the standard QCD scale Λ qcd via the minimality condition for the integrated effective action Γ, up to the critical 2-loop level, using the Cornwall-Jackiw formalism for composite operators. To that end we determine the mass function m(p) via the Schwinger-Dyson equation (as a zero of the functional derivative of Γ w.r.t S ′ F) as an input, and use the stationarity condition on Γ as function of µ and α s (µ) to obtain the ratio Λ/µ = 0.246, in fair accord with hep-ph/0109278. Inclusion up to the two-loop level has proved crucial for this agreement. The prospects of a non-perturbative formulation of QCD in terms of the B-field for a more convergent strong interaction treatment (compared to A-field) are discussed.