Pion radiative weak decays in nonlocal chiral quark models

Abstract

We analyze the radiative pion decay π+ → e+νeγ 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 q2 = 0 — where q2 is the e+νe squared invariant mass — and the slope a of F V (q2) at q2 → 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 π0 → γ ∗γ decays are discussed.