Related papers: Analysis of Pion Electroproduction Data
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…
Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at…
A partial-wave analysis of single-pion photoproduction data has been completed. This study extends from threshold to 2 GeV in the laboratory photon energy, focusing mainly on the influence of new measurements and model-dependence in the…
A recent analysis of pion photo-production multipoles using p(g,pi0) data from Mainz is repeated, successively adding constraints from other observables and varying the number of fitted partial waves. The original analysis is shown to have…
We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q^2=1.0 (GeV/c)^2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have…
We calculate the ratios $E2/M1$ and $C2/M1$ of the multipole amplitudes for electroproduction of the $\Delta$(1232) in the range of photon virtuality $0<-K^2<1$~GeV$^2$ in a chiral chromodielectric model and a linear $\sigma$-model. We find…
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…
Existing pion+nucleus Drell-Yan and electron+pion scattering data are used to develop ensembles of model-independent representations of the pion generalised parton distribution (GPD). Therewith, one arrives at a data-driven prediction for…
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…
We investigate pion photoproduction off the proton in a manifestly gauge-invariant chiral unitary extension of chiral perturbation theory. In a first step, we consider meson-baryon scattering taking into account all next-to-leading order…
We show that, within a meson-exchange dynamical model describing well most of the existing pion electromagnetic production data up to the second resonance region, one is also able to obtain a good agreement with the pi^0 photo- and…
We present a relativistic dynamical model of pion photoproduction on the nucleon in the resonance region. It offers several advances over the existing approaches. The model is obtained by extending our $\pi N$-scattering description to the…
The process $ep \to e^{\prime}p^{\prime}\pi^0$ has been measured at $Q^2$ = 6.4 and 7.7 GeV/c$^2$)$^2$ in Jefferson Lab's Hall C. Unpolarized differential cross sections are reported in the virtual photon-proton center of mass frame…
We derive expressions for pion electroproduction amplitudes in the 1/N_c expansion of QCD, and obtain from them linear relations between the electromagnetic multipole amplitudes that hold at all energies. The leading-order relations in…
The amplitudes of the pion electroproduction from the nucleon are derived up to third order in the chiral effective theory including explicit $\Delta$(1232) >. The Q^2 evolutions of weighted integrals of amplitudes are presented.
Pion 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 using the…
The neutral pion electroproduction on the proton is considered in the framework phenomenological model based on the PCAC, current algebra with hard pions and chiral symmetry breaking interaction. The s- wave differential cross-section of…
The (\pi^{-}\Delta^{++}) production on the nucleon by real and virtual photons is discussed as initial step in a simple model approach for the two pion photo- and electroproduction on the nucleon, with emphasis on nucleon resonance…
We describe the pion electroproduction processes in the $\Delta$(1232)-resonance region within the framework of chiral effective-field theory. By studying the observables of pion electroproduction in a next-to-leading order calculation we…
We present a relativistic calculation of pion scattering, pion photoproduction and Compton scattering on the nucleon in the energy region of the \Del-resonance (upto 450 MeV photon lab energy), in a unified framework which obeys the…