Related papers: Production of eta mesons in nucleon-nucleon collis…
The energy transfer spectra have been calculated for the coherent $\eta$ meson production in the proton nucleus reaction. The elementary reaction occurring in the nucleus is considered as $ pN \to pN^*(1535) $; $ N^*(1535) \to N\eta $. The…
Recent results obtained by the COSY-11 collaboration concerning the production of eta and eta' mesons in the pp --> pp Meson reaction are presented. A comparison of the production amplitude for the pi(0), eta and eta' mesons at the same…
We evaluate the threshold matrix-element for the reaction $pp \to pp\pi^0$ in a fully relativistic Feynman diagrammatic approach. We employ a simple effective range approximation to take care of the S-wave $pp$ final-state interaction. The…
Very recent data for the reaction gamma{d} --> eta{np} are analyzed within a model that includes contributions from the impulse approximation and next order corrections due to the np and eta{N} interactions in the final state. Comparison…
The $\pi$, $\eta$ and $\rho$ exchange contributions to the cross-section for the reaction $pp\to pp\eta$ near threshold are calculated with a phenomenological description of the intermediate S11 (N(1535)) resonance for all exchange…
The production of mesons in nucleon-nucleon collisions is reviewed from the viewpoint of the meson-exchange picture. In the first part various possible production mechanisms and their relative importance are discussed. In addition, general…
It is shown that the striking energy variation in the $p\, d \rightarrow \mbox{$^{\, 3}{\rm He}$}\, \eta$ cross section near threshold is probably due to a final state interaction associated with a large (complex) $\eta -\mbox{$^{3}{\rm…
The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding…
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…
The eta-prime meson production in the reaction pp-->pp eta-prime has been studied at excess energies of Q = 26.5, 32.5 and 46.6 MeV using the internal beam facility COSY-11 at the cooler synchrotron COSY. The total cross sections as well as…
The total cross section of the p d -> p d eta reaction has been measured at two energies near threshold by detecting the final proton and deuteron in a magneti spectrometer. The values are somewhat larger than expected on the basis of two…
The production near threshold of isoscalar pion pairs in the pd -> 3He(pi pi)^0 reaction is estimated in a two-step model which successfully describes the production of eta, omega and eta' mesons. A virtual pion beam, generated through an…
We study the near-threshold $\eta '$ production mechanism in nucleon-nucleon and $\pi N$ collisions under the assumption that sub-threshold resonance $N^{*}(1535)$ is predominant. In an effective Lagrangian approach which gives a reasonable…
The $\omega$-meson photoproduction, $\gamma+p\to p+\omega$, is studied in the framework of a model, containing $\pi$-meson exchange in t-channel and nucleon-exchange in s- and u-channels. Considering both $\omega NN$-coupling constants in…
We analyze the production of $\phi$ mesons in $\pi N$ and NN reactions in the near-threshold region, using throughout the conventional ``non-strange'' dynamics based on such processes which are allowed by the non-ideal $\omega-\phi$ mixing.…
Results of a combined analysis are presented for the production of $\omega$ and $\phi$ mesons in $\pi N$ reactions in the near-threshold region using throughoutly a conventional ''non-strange'' dynamics based on such processes which are…
Due to their short life-time, flavour-neutral mesons cannot be utilized as free secondary beams or targets, and therefore a study of their interaction with nucleons is not possible via direct scattering experiments. This interaction is,…
A model calculation for pion production in nucleon-nucleon collisions is presented. Direct production, pion rescattering and contributions from pair diagrams are taken into account. The amplitudes for the elementary processes are based on…
Information about the production mechanism of the eta meson in proton-proton collisions can be inferred by confronting the experimental studies on the analysing power for the p(pol)p --> pp eta reaction with the theoretical predictions of…
We calculate the quasifree photoproduction of pions and eta mesons on nuclei from 12C to 208Pb. Assuming that for the quasifree process the cross sections for pi/eta - photoproduction on a nucleon in medium are -- besides a lowering due to…