Empirical parametrizations of the resonance amplitudes based on the Siegert's theorem

We present parametrizations of the ${\gamma }^{\ast }N\to N(1535)1\mathrm{/}{2}^{-}$, ${\gamma }^{\ast }N\to N(1520)3\mathrm{/}{2}^{-}$ and ${\gamma }^{\ast }N\to \mathrm{\Delta }(1232)3\mathrm{/}{2}^{+}$ transition amplitudes that are compatible with the analytic constraints at the pseudothreshold (Siegert’s theorem). The presented parametrizations also provide a fair description of the experimental data. For the case of the ${\gamma }^{\ast }N\to \mathrm{\Delta }(1232)3\mathrm{/}{2}^{+}$ transition, we discuss how the pion cloud parametrizations of the electric and the Coulomb quadrupole form factors can be adjusted according to the Siegert’s theorem.