We obtain the electromagnetic form factors of the γNΔ transition
by analyzing recent pion-electroproduction data using a fully relativistic
dynamical model. Special care is taken to satisfy Ward-Takahashi identities for
the Born term in the presence of form factors thereby allowing the use of
realistic electromagnetic form factors of the nucleon and pion. We parametrize
the Q2 dependence of the {\it bare} γNΔ form factors by a
three-parameter form which is consistent with the asymptotic behavior inferred
from QCD. The parameters of the bare γNΔ form factors are the
only free parameters of the model and are fitted to the differential
cross-section and multipole-analysis data up to Q2=4 (GeV/c)2 in the
Δ(1232)-resonance region. This analysis emphasizes the significance of
the pion-cloud effects in the extraction of the resonance parameters.Comment: 9 pages, 5 figures, several small corrections, to be published in
Phys. Rev.