Related papers: Mesons electromagnetic production study via a cons…
The $\eta$-meson production in photon- and hadron-induced reactions, namely, $\gamma p \to p \eta$, $\pi^- p \to n \eta$, $pp \to pp\eta$, and $pn \to pn\eta$, are investigated in a combined analysis in order to learn about the relevant…
We examine the non-diffractive mechanisms in the $\phi$ meson photoproduction from threshold up to a few GeV using an effective Lagrangian in a constituent quark model. The new data from CLAS at large angles can be consistently accounted…
Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the…
Quasi-free photoproduction of eta-mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta-mesons have been detected in…
Nucleon resonances are investigated through the electromagnetic production of K-mesons. We study the kaon photoproduction process at tree-level and compare to a recently developed unitary K-matrix approach. Employing hadronic form factors…
We utilize the effective Lagrangian method within the tree-level Born approximation to explore $\phi$-meson photoproduction, i.e., $\gamma p \to \phi p$. Our analysis encompasses contributions from various sources, including the Pomeron,…
Eta meson production in both proton-proton and proton-neutron collisions is investigated within a relativistic meson exchange model of hadronic interactions. It is found that the available cross section data can be described equally well by…
Advances in the exploration of the spectrum and structure of the excited states of the nucleon from experiments with electromagnetic probes on proton targets are presented. Impressive progress has been achieved in the studies of exclusive…
The differential cross section for the reaction p(gamma, eta p) has been measured from threshold to 1100 MeV photon laboratory energy. For the first time, the region of the S11(1535) resonance is fully covered in a photoproduction…
The production of eta' mesons in photon- and hadron-induced reactions has been revisited in view of the recent additions of high-precision data to the world data base. Based on an effective Lagrangian approach, we have performed a combined…
We study the incoherent neutrinoproduction of photons and pions with neutrino energy E_{\nu} $\leqslant$ 0.5 GeV. These processes are relevant to the background analysis in neutrino-oscillation experiments, for example MiniBooNE [A. A.…
An extended $U(3)_L\bigotimes U(3)_R$ chiral theory which includes pseudoscalar and vector meson nonets as dynamic degrees of freedom is presented. We combine a hidden symmetry approach with a general procedure of including the $\eta'$…
The electromagnetic form factors of light and heavy pseudoscalar mesons are calculated within two covariant constituent-quark models, a light-front and a dispersion relation approach. We investigate the details and physical origins of the…
We apply the effective Lagrangian approach to investigate the role of the nucleon resonances in $\omega$ meson photoproduction at energies near the threshold. The resonant amplitudes are calculated from effective Lagrangians with the gamma…
A method for computing electromagnetic properties of hadrons in lattice QCD is described. The electromagnetic field is introduced dynamically, using a noncompact formulation. Employing enhanced electric charges, the dependence of the…
We study the near-threshold $\Upsilon(1S)$ meson photoproduction from protons and nuclei by considering incoherent direct non-resonant (${\gamma}p \to {\Upsilon(1S)}p$, ${\gamma}n \to {\Upsilon(1S)}n$) and two-step resonant (${\gamma}p \to…
The photoproduction of $\omega$ mesons on LH_2, C and Nb has been studied for incident photon energies from 900 to 1300 MeV using the CB/TAPS detector at ELSA. The $\omega$ line shape does not show any significant difference between the…
The CEBAF Large Acceptance Spectrometer for operation at 12 GeV (CLAS12) at the Thomas Jefferson National Accelerator Facility has played a central role in advancing the understanding of nucleon and nuclear structure. As increasingly…
Total and differential cross sections for $\eta$ and $\eta ^\prime$ photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The $\eta$ mesons are detected in their two…
The main goal of the spectroscopy program at COMPASS is to explore the light-meson spectrum in the mass range below about $2\,\text{GeV}/c^2$ using diffractive dissociation reactions. Our flagship channel is the production of three charged…