Related papers: Meson resonances in forward-angle $\pi^+\pi^-$ pho…
The photoproduction processes gp-->a0(980)p and gp-->f0(980)p at energies close to threshold are considered. These reactions are studied in the \pi\pi p, \pi\eta p, and K-barK p channels. Production cross sections are estimated in different…
The differential cross sections and unpolarized spin-density matrix elements for the reaction $\gamma p\to p\omega$ were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV.…
A fit of the experimental data to the total cross section of the process $\gamma\gamma->\pi^+\pi^-$ in the energy region from threshold to 2500 MeV has been carried out using dispersion relations with subtractions for the invariant…
Considering, as a limit case, an approximately flat pion distribution amplitude, which is determined from the hardest, in momentum space, solution of the Bethe-Salpeter equation for the pion wave function, we compute the pion transition…
The LEPS and CLAS data of the incoherent photoproduction of $\phi$ meson from deuteron at low energies are studied with a model for $\phi$ meson photoproduction from nucleon consisting of Pomeron, $\pi$, and $\eta$ meson exchanges in the…
We fitted the pi-pi mass distribution in the range 0.5 < mpipi < 1.1 GeV measured in hard exclusive positron-proton reactions at HERA by the form dictated by QCD at leading twist level. Extracted parameters are related to valence quark…
Systematic analysis of available data for $\omega$-meson photoproduction is given in frame of Regge theory. At photon energies above 20 GeV the $\gamma{+}p{\to}\omega{+}p$ reaction is entirely dominated by Pomeron exchange. However, it was…
A fit to the existing pion electroproduction data is presented. This work builds upon our previous analyses of pion photoproduction and elastic pion-nucleon scattering over the Delta resonance region. We comment on the extraction of E_1+…
The complete one-loop QED initial state, final state and initial--final state interference corrections to the process e+e- -> pi+pi- are presented. Analytic formulae are given for the virtual and for the real photon corrections. The total…
We present a theoretical study of the $\gamma\gamma^{*} \to \pi^+\pi^-, \pi^0\pi^0$ processes from the threshold through the $f_2(1270)$ region in the $\pi\pi$ invariant mass. We adopt the Omn\`es representation in order to account for…
The process $\gamma p \to \phi p$ close to threshold is investigated focusing on the role played by the {\it s}- and {\it u}-channel nucleonic resonances. For this purpose, a recent quark model approach, based on the $SU(6)\otimes O(3)$…
A partial wave analysis (PWA) of the $\pi^- \pi^- \pi^+$ and $\pi^- \pi^0 \pi^0$ systems produced in the reaction $\pi^- p \to (3\pi)^-p$ at 18 GeV/$c$ was carried out using an \emph{isobar} model assumption. This analysis is based on 3.0M…
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…
The electromagnetic pion production reactions are investigated within the dynamical coupled-channels model developed in {\bf Physics Reports, 439, 193 (2007)}. The meson-baryon channels included in this study are $\gamma N$, $\pi N$, $\eta…
We point out that the $\Delta\pi$ component of the nucleon wave function is vital to the interpretation of the recent H1 data for leading baryon production. While the $n/p$ ratio is equal to two with the $N\pi$ component alone, the…
In this work, the cross sections of $\phi$ photoproduction are systematically investigated with the two gluon exchange model and the pomeron model. The results obtained show that the theoretical values of the two models agree well with the…
We report calculations for exclusive pion photoproduction on nuclei beyond the first resonance region in the distorted wave impulse approximation. The elementary operator contains contributions from the resonances $P_{33}(1232)$,…
The resonance model is used to analyze the omega- and phi-meson angular distributions in proton-proton collisions at sqrt{s} = 2.83 and 2.98 GeV. The assumption of dominant contributions from N^*(1720)3/2+ and N^*(1900)3/2+ resonances which…
We investigate the exclusive proton-induced $K^+$ production near the kaon threshold. Compared are two models: a meson-exchange model, which includes $\pi$, \rho$, $K$ and $K^\ast$ exchange, together with the dominant baryon resonances, and…
We investigate the reaction mechanism of the $\phi$-meson photoproduction off the proton target, i.e., $\gamma p\to\phi p$, up to $\sqrt{s}=2.8$ GeV. For this purpose, we employ an effective Lagrangian approach in the tree-level Born…