I review to which extent the properties of pseudoscalar mesons can be understood in terms
of the underlying quark (and eventually gluon) structure. Special emphasis is put on the …

The last decade has witnessed great experimental progress that has led to measurements of
near-threshold cross sections—polarized as well as unpolarized—of high accuracy for …

A review of the present understanding of η′ and η meson physics and these mesons as a
probe of gluon dynamics in low-energy QCD is presented. Recent highlights include the …

Total and differential cross sections for the dp→ He3η reaction have been measured near
threshold for He3 center-of-mass momenta in the range from 17.1 MeV/c to 87.5 MeV/c. The …

The total cross section of the pp→ pp η′ reaction has been measured at two energies near
threshold by detecting the final protons in a magnetic spectrometer. The values obtained are …

Studies of meson production at threshold in the hadron-hadron interaction began in the
fifties when sufficient energies of accelerated protons were available. A strong …

The production of η and η′ mesons in photon-and hadron-induced reactions on free and
quasi-free nucleons and on nuclei is reviewed. The extensive database on γ N→ η N, for …

Total cross sections for the pp→ ppη′ reaction have been measured in the excess energy
range from Q= 1.53 MeV to Q= 23.64 MeV. The experiment has been performed at the …

A high statistics measurement of the pp→ pp η reaction at an excess energy of Q= 15.5 MeV
has been performed at the internal beam facility COSY-11. The stochastically cooled proton …

We describe a novel technique for comparing total cross sections for the reactions pp→
ppπ0, pp→ ppη, and pp→ ppη′ close to threshold. The initial and final state proton-proton …