Coherent ω photoproduction from nuclei and ω properties in nuclear matter. Abstract. The coherent ω-meson photoproduction from nuclei is proposed as a phenomenological method to evaluate the momentum dependence of ω-meson mass shift and width in nuclear matter. We analyze available data on un-separated coherent and incoherent ω-meson photoproduction from nuclei and extract the imaginary part of...

We improve the calculations of the h→p0gg 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 long standing sign ambiguity on its contribution. This also allows us to calculate the loops with one vector meson exchange, thus removing a former source of uncertainty. In addition...

We study coherent and incoherent φ-meson photoproduction from nuclei. The available data are analyzed in terms of single and coupled channel photoproduction. It is found that the data on coherent photoproduction can be well reproduced within a single channel optical model and show only little room for ω− φ mixing. These data indicate a normal distortion of the φ-meson in nuclei, which is compat...

The fermion and meson sectors of the quark-level SU(2) linear sigma model are dynamically generated from a meson-quark Lagrangian, with the quark (q) and meson (σ, π) fields all treated as elementary, having neither bare masses nor expectation values. In the chiral limit, the masses are predicted to be mq = fπg, mπ = 0, mσ = 2mq, and we also find that the quark-meson coupling is g = 2π/ √ Nc, t...

We present a unified theoretical picture which studies simultaneously the γγ → π + π − , π 0 π 0 , K + K − , K 0 ¯ K 0 , π 0 η reactions up to about √ s = 1.4 GeV reproducing the experimental cross sections. The present work implements in an accurate way the final state interaction of the meson-meson system, which is shown to be essential in order to reproduce the data, particularly the L = 0 c...

We discuss the non–relativistic multichannel quark model and describe the techniques developed to solve the resulting equations. We then investigate some simple solutions to demonstrate how the model unifies meson–meson scattering with meson spectroscopy, thereby greatly extending the domain of applicability of the näıve quark model. In the limits of narrow resonance widths and no quark exchang...

we used qcd factorization for the hadronic matrix elements to show that the existing data, in particular the branching ratios br ( ?j/?k) and br ( ?j/??), can be accounted for this approach. we analyzed the decay within the framework of qcd factorization. we have complete calculation of the relevant hard-scattering kernels for twist-2 and twist-3. we calculated this decays in a special scale ( ...

The isovector–vector and the isovector–axial-vector current are related by a chiral transformation. These currents can be called chiral partners at the fundamental level. In a world where chiral symmetry was not broken, the corresponding current-current correlators would show the same spectral information. In the real world chiral symmetry is spontaneously broken. A prominent peak — the ρ-meson...

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.