Photon-3-Pion And Pion-2-Photon Form Factors From Dynamical Constituent Quarks

Abstract

We study the form factors of the low energy anomalous pion-2-photon and photon-3-pion processes in the nonlocal chiral quark model which incorporates the momentum dependence of the dynamical quark mass and realizes correctly the chiral symmetries. The obtained slope parameter for pion-2-photon is in reasonable agreement with the direct experimental results but smaller than the ones invoking vector meson dominance. Our result for the photon-3-pion form factor interpolates between the two extremes of theoretical approaches, with the largest one provided by the vector meson dominance and the smallest one by the Schwinger-Dyson approach. But all of them are well below the single data point available so far. This situation will hopefully be clarified by the experiments at CEBAF and CERN.

Comments: 15 pages, Latex, 2 figs using Axodraw. Minor changes: (1) more detailed description of the model; (2) some re-wording for clarification