Adler function and hadronic contribution to the muon g-2 in a nonlocal chiral quark model

Abstract

The behavior of the vector Adler function at spacelike momenta is studied in the framework of a covariant chiral quark model with instantonlike quark-quark interaction. This function describes the transition between the high-energy asymptotically free region of almost massless current quarks to the low-energy hadronized regime with massive constituent quarks. The model reproduces the Adler function and $V\ensuremath{-}A$ correlator extracted from the ALEPH and OPAL data on hadronic $\ensuremath{\tau}$ lepton decays, transformed into the Euclidean domain via dispersion relations. The leading order contribution from the hadronic part of the photon vacuum polarization to the anomalous magnetic moment of the muon, ${a}_{\ensuremath{\mu}}^{\mathrm{h}\mathrm{v}\mathrm{p}(1)}$, is estimated.