Axial amplitudes for Delta excitation in chiral quark models

Abstract

We study the axial amplitudes for the N-Delta 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 C^A_5 amplitude as well as the piNDelta strong coupling constant. We show that the results are considerably improved in models that, in addition to the pion cloud, incorporate a fluctuating sigma field inside the baryon.

Comments: 13 pages LaTeX2e, 4 EPS figures within the text; Requires elsart.cls (Submitted for publication in Phys. Lett. B). Section 4 revised