Related papers: N*(1535) electroproduction at high Q2
The C2/M1 ratio of the electromagnetic N->Delta(1232) transition, which is important for determining the geometric shape of the nucleon, is shown to be related to the neutron elastic form factor ratio G_C^n/G_M^n. The proposed relation…
We investigate the $K \Lambda$ strong interaction dynamics around the energy region of $N^*(1535)$ resonance through femtoscopic correlation functions within the Koonin-Pratt formalism, where coupled-channel effects of $\pi N$, $K\Lambda$,…
Electron scattering at large Q^2 probes a nucleon's quark core. This core's contribution to electromagnetic form factors may be calculated using Poincare' covariant Faddeev amplitudes combined with a nucleon-photon vertex that automatically…
Within the dynamical model of Refs. [Phys. Rev. C54, 2660 (1996); C63, 055201 (2001)], we perform an analysis of recent data of pion electroproduction reactions at energies near the Delta(1232) resonance. We discuss possible interpretations…
We present analytic parametrizations for the $\gamma^\ast N \to N(1440)$ form factors derived from light-front holography in leading twist approximation. The new parametrizations describe the electromagnetic form factors using analytic…
Experiments at Jefferson Laboratory, MIT-Bates, LEGS, Mainz, Bonn, GRAAL, and Spring-8 offer new opportunities to understand in detail how nucleon resonance ($N^*$) properties emerge from the nonperturbative aspects of QCD. Preliminary data…
We perform a calculation of the relativistic corrections to the electromagnetic elastic form factors of the nucleon obtained with various Constituent Quark Models. With respect to the non relativistic calculations a substantial improvement…
We present the results of the covariant spectator quark model applied to the nucleon structure function $f(x)$ measured in unpolarized deep inelastic scattering, and the structure functions $g_1(x)$ and $g_2(x)$ measured in deep inelastic…
The reactions gamma p -> K+ Lambda and gamma p -> K* Lambda are analyzed within perturbative QCD, allowing for diquarks as quasi-elementary constituents of baryons. The diquark-model parameters and the quark-diquark distribution amplitudes…
The application of relativistic constituent quark models to the evaluation of the electromagnetic properties of the nucleon and its resonances is addressed. The role of the pair creation process in the Feynmann triangle diagram is discussed…
The covariant quark model is shown to allow a phenomenological description of the neutron electric form factor, G_E^n(Q^2), in the impulse approximation, provided that the wave function contains minor (~ 3 %) admixtures of the lowest…
A covariant quark model, based both on the spectator formalism and on vector meson dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra…
The $\gamma^\ast \gamma \to \pi^0$ transition form factor, $G(Q^2)$, is computed on the entire domain of spacelike momenta using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory: the…
The nucleon form factors are calculated using a non-relativistic description in terms of constituent quarks. The emphasis is put on the reliability of present numerical methods used to solve the three-body problem in order to correctly…
We study the $\gamma^\ast \Lambda \to \Sigma^0$ transition form factors by applying the covariant spectator quark model. Using the parametrization for the baryon core wave functions as well as for the pion cloud dressing obtained in a…
The amplitudes of the transition gamma* N -> P11(1440) are calculated within light-front relativistic quark model assuming that the P11(1440) is the first radial excitation of the 3q ground state. The results are presented along with the…
The ratio $R_p$ between the electric and magnetic proton form factors has been recently measured at JLab up to $Q^2=8.5 ~GeV^2$. We have extended the calculation of the nucleon form factors with the hypercentral Constituent Quark Model and…
Data on single- and double-charged pion electroproduction off protons are successfully described in the second and third nucleon resonance regions with common N* photocouplings. The analysis was carried out using separate isobar models for…
We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited…
I give an overview on experimental studies of the spectrum and the structure of the excited states of the nucleon and what we can learn about their internal structure. One focus is on the efforts to obtain a more complete picture of the…