Related papers: Angular dependence of eta photoproduction in photo…
The presently available data for the reaction ${\gamma}p{\to}\eta^\prime{p}$ are analyzed in terms of a model in which the dominant production mechanism is the exchange of the vector mesons $\omega$ and $\rho$. To describe the data at…
The production of $\eta$ and $\eta^\prime$ mesons in photon- and hadron-induced reactions are studied in a combined analysis based on an effective Lagrangian approach in order to learn about the relevant production mechanisms and the…
Eta photo- and electroproduction off the nucleon is investigated in an effective lagrangian approach that contains Born terms and both vector meson and nucleon resonance contributions. In particular, we review and develop the formalism for…
We present a unitary and gauge-invariant model with coupled channels, which provides a consistent description of pion photoproduction off nucleons in the E$_{0+}$ channel and eta-meson photoproduction off protons and deuterons. An effective…
We study the influence of the nucleon spectral function on eta photo- and electroproduction on nuclei. Besides kinematical effects due to groundstate correlations, also a modification of the S11(1535) decay width is taken into account,…
An effective field theory with hadrons and photons is constructed, where the hadronic parameters are determined by fitting elastic $\pi$N scattering data. The predicted pion-induced $\eta$-production on the nucleon agrees well with the…
In an unitary effective Lagrangian model we develop a unified description of both meson scattering and photon-induced reactions on the nucleon. Adding the photon to an already existing model for meson-nucleon scattering yields both Compton…
The photoproduction of $\eta$-mesons off nucleons bound in $^2$H and $^3$He has been measured in coincidence with recoil protons and recoil neutrons for incident photon energies from threshold up to 1.4 GeV. The experiments were performed…
Photoproduction of $\eta$-mesons off deuteron is studied within the Alt-Grassberger-Sandhas formalism for different parameters of $\eta N$ interaction. The calculations revealed peaks in the energy dependence of the total cross-section.
Photoproduction of $\eta$ mesons from neutrons} \abstract{Results from measurements of the photoproduction of $\eta$ mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at…
The $\eta N$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $\Delta$ states. To this end, the world database on eta photoproduction off the proton up to a…
The isobar models eta-MAID and eta'-MAID have been used to analyze new data on quasi-free eta photoproduction on the deuteron from Bonn and recent eta' data on the proton from Jlab. In eta photoproduction on the neutron a bump around W=1700…
Photoproduction of $\eta$ mesons off $^{12}$C, $^{40}$Ca, $^{93}$Nb, and $^{nat}$Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2 GeV. The experiment was performed at the Bonn ELSA accelerator with the…
The recent high-precision data for the reaction $\gamma p\to p\eta'$ at photon energies in the range 1.5--2.3 GeV obtained by the CLAS collaboration at the Jefferson Laboratory have been analyzed within an extended version of the…
We study the photoproduction of vector mesons off proton and off nuclear targets. We work within the colour dipole model in an approach that includes subnucleon degrees of freedom, so-called hot spots, whose positions in the…
We study the photoproduction of $\eta^\prime$ mesons from nuclei near the threshold within the collision model based on the nuclear spectral function. The model takes properly into account both primary photon-nucleon and secondary…
Photo- and electroproduction of pions and eta-mesons is studied on the nucleon. The formalism of such reactions is presented including polarization degrees of freedom and theoretical approaches are discussed. In particular, the threshold…
Using the Green function method, binding effects on produced eta-mesons in the two-stage reaction \gamma + A \to N + \eta + (A-1) \to N + (\pi N) + (A-2) are studied. The energy spectrum of the correlated pi-N pairs which arise from decays…
Differences in the photoproduction of mesons on the free proton and on nuclei are expected to reveal changes in the properties of hadrons. Inclusive studies of nuclear photoabsorption have provided evidence of medium modifications. However,…
First experimental results on photoproduction of eta-mesic nuclei are analyzed. In an experiment performed at the 1 GeV electron synchrotron of the Lebedev Physical Institute, correlated pi+n pairs arising from the reaction gamma + 12C -> N…