Related papers: Double and single pion photoproduction within a dy…
Results of the recently developed unitary isobar model (MAID) are presented for the spin asymmetries, structure functions and relevant sum rules in the resonance region. The model describes the presently available data for single-pion…
We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states gamma N, pi N, 2 pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass up to…
Recently we presented a successful strategy to extract the position of the two $\Lambda(1405)$ poles from experimental photoproduction data on the $\gamma p \to K^+ \pi^0 \Sigma^0 $ reaction at Jefferson Lab. Following a similar strategy,…
Inclusive single pion photoproduction on the deuteron is studied in the first resonance region. The calculation is based on the use of the diagrammatic approach. Pole diagrams and one-loop diagrams with NN rescattering in the final state…
The total cross section for Coulomb photoproduction of neutral pion pairs in the reaction gamma A --> pi0 pi0 A is estimated within the effective chiral lagrangian approach. The amplitude of gamma gamma* --> pi0 pi0 with one off-shell…
A calculation of the angular moments of two-pion photoproduction is presented. The underlying theoretical model encodes the prominent $\rho(770)$ resonance and the expected leading background contribution coming from the Deck mechanism. The…
The pi N --> KY and KY --> KY reactions are studied using a dynamical coupled-channel model of meson-baryon interactions at energies where the baryon resonances are strongly excited. The channels included are: pi N, K \Lambda, and K\Sigma.…
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…
We have investigated the neutrino induced coherent pion production reaction at low and intermediate energies including pion, nucleon and Delta(1232) resonance. Medium effects in the production mechanism and the distortion of the pion wave…
We present a systematic analysis of backward pion photoproduction for the reactions gamma p -> pi0 p and gamma p -> pi+ n. Regge phenomenology is applied at invariant collision energies above 3 GeV in order to fix the reaction amplitude. A…
One-loop corrections due to the intermediate $\pi N$ and $\rho N$ states are studied in $\omega$ photoproduction near threshold. Our results show that the coupled-channel effects should be taken into account in extracting reliable nucleon…
Two-pion photoproduction in the reaction gamma + p -> p + pi^+ + pi^- has been studied at Jefferson Lab Hall B using a circularly-polarized tagged photon beam in the energy range between 0.6 GeV and 2.3 GeV. Owing to the large angular…
We present a high-statistics measurement of differential cross sections and the total cross section for the process gamma gamma -> pi^0 pi^0 in the kinematic range 0.6 GeV <= W <= 4.0 GeV and |cos theta*| <= 0.8, where W and theta* are the…
The reaction $\gamma p \to \pi^0 \pi^0 p$ has been measured using the TAPS BaF$_2$ calorimeter at the tagged photon facility of the Mainz Microtron accelerator. Chiral perturbation theory (ChPT) predicts that close to threshold this channel…
Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the $\Delta(1232)$ resonance is investigated. The calculations include an impulse term and one-loop contributions…
The yield of the $^{16}$O$(\gamma ,\pi^{+} p)$ reaction has been measured in the region of the excitation of the $\Delta(1232)$ isobar at high momentum transfers to the residual nuclear system. The experimental data are interpreted within…
Results of new analysis of pion photoproduction data obtained with Dynamical and MAID models are presented
We show that, within a meson-exchange dynamical model describing 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 pi0 photo- and…
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…
The $\eta$ production in the nucleon resonance energy region is studied within the unitary coupled-channels effective Lagrangian approach of the Giessen model. We demonstrate that the second peak recently observed in the cross section of…