The role of the pion cloud in electroproduction of the

We calculate the ratios E2M1 and C2M1 of the multipole amplitudes for electroproduction of the Δ(1232) in the range of photon virtuality 0 < −K2 < 1 GeV2 in a chiral chromodielectric model and a linear σ-model. We find that relatively large experimental values can be explained in terms of the pion contribution alone; the contribution arising from d-state quark admixture remains below 10%. We describe the pion cloud as a coherent state and use spin and isospin projection to obtain the physical nucleon and the Δ. The A12 and A32 amplitudes are reasonably well reproduced in the σ-model; in the chromodielectric model, however, they are a factor of two too small.