The gluon/charm content of the eta' meson and instantons

Motivated by recent CLEO measurements of the B-->\eta' K decay, we evaluate gluon/charm content of the eta' meson using the interacting instanton liquid model of the QCD vacuum. Our result is very large due to the strong field of small-size instantons. We show that it provides quantitative explanations of the CLEO data on the B-->\eta' K decay rate (as well as inclusive process B-->\eta' X), via a virtual Cabbibo-unsuppressed decay into \bar c c pair which then becomes eta'. If so, a significant charm component should be present in other hadrons also. In particular, we found a large contribution of the charmed quark in the polarised deep-inelastic scattering on a proton.Comment: 6 pages, LATE

pp→ppωpp\to pp\omega reaction near threshold

We analyze the total cross section data for $pp \to pp\omega$ near threshold measured recently at SATURNE. Using an effective range approximation for the on-shell $pp$ S-wave final state interaction we extract from these data the modulus $|\Omega| = 0.53$ fm$^4$ of the threshold transition amplitude $\Omega$. We present a calculation of various (tree-level) meson exchange diagrams contributing to $\Omega$. It is essential that $\omega$-emission from the anomalous $\omega\rho\pi$-vertex interferes destructively with $\omega$-emission from the proton lines. The contribution of scalar $\sigma$-meson exchange to $\Omega$ turns out to be negligibly small. Without introducing off-shell meson-nucleon form factors the experimental value $|\Omega|=0.53$ fm$^4$ can be reproduced with an $\omega N$-coupling constant of $g_{\omega N}=10.7$. The results of the present approach agree qualitatively with the J\"ulich model. We also perform a combined analysis of the reactions $pp\to pp\pi^0, pn\pi^+, pp\eta, pp\omega$ and $pn\to pn\eta$ near threshold.Comment: Latex-file 6 pages, 2 Figure

One-rank interaction kernel of the two-nucleon system for medium and high energies

A new version of the separable kernel of the nucleon-nucleon interaction in the Bethe-Salpeter approach is presented. The phase shifts are fitted to recent experimental data for singlet and uncoupled triplet partial waves of the neutron-proton scattering with total angular momenta J=0,1. The results are compared with other model calculations.Comment: 10 pages, 5 figures, 3 table