Axial amplitudes for Δ excitation in chiral quark models

We study the axial amplitudes for the N–Δ transition in models with quarks and chiral mesons. A set of constraints on the pion field is imposed which enforces PCAC and the off-diagonal Goldberger–Treiman relation. The quark contribution to the amplitudes in general strongly underestimates the CA5 amplitude as well as the πNΔ strong coupling constant. We show that the results are considerably improved in models that, in addition to the pion cloud, incorporate a fluctuating σ-field inside the baryon.