Related papers: Electroexcitation of nucleon resonances from CLAS …
In view of the major advances achieved by the CLAS experiments in studying the N* electroexcitation amplitudes, as well as further extension of these studies in the experiments with CLAS12, we present an approach for the evaluation of the…
Pion scattering and electro-production amplitudes have been computed in a coupled-channel framework incorporating quasi-bound quark-model states, based on the Cloudy Bag model. All relevant low-lying nucleon resonances in the P33, P11, and…
Recent results on nucleon resonance studies in $\pi^{+}\pi^{-}p$ electro- production off protons with the CLAS detector are presented. The analysis of CLAS data allowed us to determine all essential contributing mechanisms, providing a…
The emergence of hadron mass represents one of the most challenging and still open problems in contemporary hadron physics. The results on the nucleon resonance electroexcitation amplitudes available from the CLAS data on $\pi N$ and…
We present a calculation of single pion electroproduction cross sections on heavy targets in the kinematic region of the Delta(1232) resonance. Final state interactions of the pions are taken into account using the pion multiple scattering…
A self-consistent analysis of pion scattering and pion photoproduction within a coupled channels dynamical model is presented. In the case of pion photoproduction, we obtain background contributions to the imaginary part of the S-wave…
We consider resonance production by neutrinos focusing on the dominant resonance $P_{33}$ at low energies with a detailed discussion of its form factors. The results are presented for free nucleon targets. The $\Delta$ resonance is…
A partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid from threshold up to 500 MeV. In the resonance region we have precisely determined the electromagnetic properties of…
We present an overview of dynamic and related models for pion electroproduction on the nucleon due to Delta(1232) excitation. The electromagnetic multipoles and their ratios obtained from these models and from effective field theories are…
The analysis of the nine 1-fold differential cross sections for the $\gamma_{r,v} p \to \pi^+\pi^-p$ photo- and electroproduction reactions obtained with the CLAS detector at Jefferson Laboratory was carried out with the goal to establish…
We utilize a light-front relativistic quark model to predict the 3q core contribution to the electroexcitation of nucleon resonances of the [70,1-] multiplet on the proton and neutron at Q2 < 5GeV2. The investigation is stimulated in large…
We perform an updated coupled-channel analysis of eta-meson production including all recent photoproduction data on the proton. The dip observed in the differential cross sections at c.m. energies W=1.68 GeV is explained by destructive…
The charge-exchange break-up of polarised deuterons pol{d}p -> {pp}n, where the final {pp} diproton system has a very low excitation energy and hence is mainly in the 1S0 state, is a powerful tool to probe the spin-flip terms in the…
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…
Transition helicity amplitudes $\gamma_{v}NN^*$ (electrocouplings) were determined for prominent excited proton states with masses below 1.8 GeV in independent analyses of major meson electroproduction channels: $\pi^{+}n$, $\pi^0p$ and…
Pion electro- and photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta(1232)$ resonance.…
Recent CLAS data on the $p\pi^+\pi^-$ electroproduction off protons at 1.3$<$W$<$1.57 GeV and 0.25$<$$Q^{2}$$<$0.6 GeV$^{2}$ have been analyzed using a meson-baryon phenomenological model. By fitting nine 1-fold differential cross section…
An expansion of the electromagnetic form factors of the nucleon and Delta(1232) in small momentum transfer and pion mass is performed in a manifestly-covariant EFT framework consistent with chiral symmetry and analyticity. We present the…
We investigate the electroproduction of eta mesons below a center of momentum energy of 1.6 GeV, with particular emphasis on the roles of the N*(1535) and N*(1520) resonances. Using the effective Lagrangian approach, we show that the…
We study the effects of the $\Delta$(1232) resonance as an effective degree of freedom for charged and neutral pion photo-production on nucleons. Different observables have been calculated for these processes by using relativistic chiral…