Pion radiative weak decays in nonlocal chiral quark models

Abstract We analyze the radiative pion decay π + → e + ν e γ within nonlocal chiral quark models that include wave function renormalization. In this framework we calculate the vector and axial-vector form factors F V and F A at q 2 = 0 — where q 2 is the e + ν e squared invariant mass — and the slope a of F V ( q 2 ) at q 2 → 0 . The calculations are carried out considering different nonlocal form factors, in particular those taken from lattice QCD evaluations, showing a reasonable agreement with the corresponding experimental data. The comparison of our results with those obtained in the (local) NJL model and the relation of F V and a with the form factor in π 0 → γ ⁎ γ decays are discussed.