A Dynamical Model for the Resonant Multipoles and the Δ Structure

الأصل · EN

We show that recent experiment data for the ratios E₁₊/M₁₊ and S₁₊/M₁₊ can be explained in a dynamical model for electromagnetic production of pions, together with a simple scaling assumption for the bare γ* N Δ form factors. Within our model we find that the bare Δ is almost spherical and the electric E2 and Coulomb C2 quadrupole excitations of the physical Δ are nearly saturated by pion cloud contribution in Q² ≤ 4.0 GeV².