A Dynamical Model for the Resonant Multipoles and the Δ Structure

2000/05/03 by S. S. Kamalov, Kamalov, S. S., S. N. Yang +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th) #hep-ph #nucl-th

paper · pdf · doi:10.48550/arxiv.nucl-th/0005007

8 pages, 2 figures, to appear in the Proc. of "NSTAR2000 - The Physics of Excited Nucleons", Feb. 16-19, 2000, Jefferson Lab, USA, World Scientific, Singapore, 2000

arxiv created 2000/05/04 · arxiv updated 2009/11/30

Abstract

We show that recent experiment data for the ratios E_1⁺/M_1⁺ and S_1⁺/M_1⁺ 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.

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