Pion electro-production in the Roper region in chiral quark models

Abstract

We present a method to calculate pion electro-production amplitudes in a coupled-channel framework incorporating quasi-bound quark-model states. The method offers a clear prescription how to extract the resonant part of the amplitudes, even in the presence of different decay channels and a strong mixing of neighbouring resonances. The method is applied to the calculation of the M1- and the S1- amplitudes in the P11 partial wave in a simple chiral quark model. A good agreement with the observed M1- amplitude is found with a significant contribution from the pion cloud. The same effect is also prominent in the S1- amplitude but a rather uncertain data prevent us to draw a definitive conclusion.

8 pages, 10 Postscript figures, Fig. 7 and Fig. 8 changed

References in corpus (5)

• Unitary Isobar Model - MAID2007
• Dynamical coupled-channel model of meson production reactions in the nucleon resonance region
• Electroexcitation of the Roper resonance in the relativistic quark models
• Empirical transverse charge densities in the nucleon-to-P11(1440) transition
• Roper resonances in chiral quark models

Cited by in corpus (18)

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• Nucleon resonances in AdS/QCD
• Hamiltonian effective field theory study of the ${\mathbf{N}}^{\ast }(1440)$ resonance in lattice QCD
• Valence quark contributions for the gamma N -> P11(1440) form factors
• Structure of the Roper Resonance from Lattice QCD Constraints
• Electroproduction of the Roper resonance on the proton: the role of the three-quark core and the molecular N-sigma component
• Electromagnetic Transition Form Factors of Baryon Resonances
• Electromagnetic transition form factors of the Roper resonance in effective field theory
• A chiral quark model for meson electro-production in the region of D-wave resonances
• Valence quark contributions for the ${\gamma }^{\ast }N\to N(1440)$ form factors from Light-Front holography
• Electromagnetic structure of the nucleon and the Roper resonance in a light-front quark approach
• A chiral quark model for meson electro-production in the S11 partial wave
• The Roper resonance: a genuine quark state or a dynamically generated structure?
• Eta and kaon production in a chiral quark model
• Dynamical generation of resonances in the P33 partial wave
• The $\Lambda (1405)$ resonance as a genuine three-quark or molecular state
• Investigation of $\Delta (1232)$ resonance substructure in $p{\gamma }^{\ast }\to \Delta (1232)$ process through helicity amplitudes