1996/01/31 by M. Fiolhais, B. Golli, S. Širca +1 · 2 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1016/0370-2693(96)00130-x
published as Phys.Lett. B373 (1996) 229-234 · 10 pages LaTeX2e, 3 LaTeX figures within the text; Requires elsart.cls (included in the self-unpacking uuencoded gzipped file). (Accepted for publication in Phys. Lett. B)
arxiv created 1996/01/31 · openalex publication_date 1996/04/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We calculate the ratios E2/M1 and C2/M1 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 A1/2 and A3/2 amplitudes are reasonably well reproduced in the σ-model; in the chromodielectric model, however, they are a factor of two too small.