Reconciling the analytic QCD with the ITEP operator product expansion philosophy

Abstract

Analytic QCD models are those versions of QCD in which the running coupling parameter a(Q^2) has the same analytic properties as the spacelike physical quantities, i.e., no singularities in the complex Q^2 plane except on the timelike semiaxis. In such models, a(Q^2) usually differs from its perturbative analog by power terms ~(Lambda^2/Q^2)^k for large momenta, introducing thus nonperturbative terms in spacelike physical quantities whose origin is the UV regime. Consequently, it contradicts the ITEP-OPE philosophy which states that such terms can come only from the IR regimes. We investigate whether it is possible to construct analytic QCD models which respect the ITEP-OPE philosophy and, at the same time, reproduce not just the high-energy QCD observables, but also the low-energy ones, among them the well-measured semihadronic tau decay ratio.

33 pages, 13 figures, 7 tables; grammatical corrections in the text; to appear in PRD