We consider the fidelity of vector meson dominance (VMD) assumption as an instrument for relating electromagnetic vector-meson production reaction $e + p \to e^\prime V p$ to purely hadronic process $V V+p$. Analyses photon vacuum polarisation and photon-quark vertex reveal that such a VMD Ansatz might be reasonable light vector-mesons. However, when vector-mesons are described by momentum-depe...

using qcd factorization for the hadronic matrix elements, we show that existing data, inparticular the branching ratios br ( b →j/ψk) and br ( b →j/ψπ), can be accounted for in this approach.we analyze the decay b j /k( ) within the framework of qcd factorization. the calculation of therelevant hard-scattering kernels for twist-2 and twist-3 is completed. we calculate this decay in a special...

A non-perturbative method which combines constraints from chiral symmetry breaking and coupled channel unitarity is used to describe the meson-meson interaction up to about 1.2 GeV. The approach uses the O(p2) and O(p4) chiral Lagrangians. The seven free parameters of the O(p4) Lagrangian are fitted to the data. The results are in good agreement with a vast amount of experimental analyses. The ...

We discuss two descriptions of the nucleon’s strange vector form factors in the framework of vector meson dominance. The first, an updated and extended version of Jaffe’s dispersion analysis, approximates the spectral functions of the form factors as a sum of vector meson poles, whereas the second combines vector meson dominance in the ω and φ meson sector with an intrinsic strangeness distribu...

A complete set of formulae in terms of the moment–operator expansion is presented for the two-meson, two-photon and fermion-antifermion states that can be used in the analysis of scalar (S) and pseudoscalar (P ) meson production in pp̄ and γγ collisions: pp̄ → SS,PP, SP and γγ → SS,PP, SP . Method of a generalization of the formulae for amplitudes of multi-meson production in the two-stage proces...

In this paper we propose a knot model of the π mesons. In this knot model we give the formation of the π meson by strong interaction and the decay of the π meson to the moun μ and the moun neutrino νμ by weak interaction. We give a mass machanism for the generation of the masses of the π 0 meson, π meson, the moun μ and the moun neutrino νμ. PACS numbers: 12.90.+b, 12.40.Yx, 12.10.Dm.

The D-meson properties in dense nuclear matter are studied. The D-meson spectral density is obtained within the framework of a coupled-channel self-consistent calculation assuming, as bare meson-baryon interaction, a separable potential. The Λc(2593) resonance is generated dynamically in our coupled-channel model. The medium modifications of the D-meson properties due to Pauli blocking and the ...

Discussion of the η → π 0 γγ decay within a chiral unitary approach We improve the calculations of the η → π 0 γγ decay within the context of meson chiral lagrangians. We use a chiral unitary approach for the meson-meson interaction, thus generating the a0(980) resonance and fixing the longstanding sign ambiguity on its contribution. This also allows us to calculate the loops with one vector me...

Two-meson-exchange nucleon-nucleon potentials are derived where either one or both nucleons contains a pair vertex. Physically, the meson-pair vertices are meant to describe in an effective way (part of) the effects of heavy-meson exchange and meson-nucleon resonances. From the point of view of " duality, " these two kinds of contribution are roughly equivalent. The various possibilities for me...