We present a relativistic and unitary approach to pion-and photon-nucleon scattering taking into account the πN , ρN , ωN , ηN , π∆, KΛ and KΣ channels. Our scheme dynamically generates the sand d-wave nucleon resonances N in terms of quasi-local two-body interaction terms. We obtain a fair description of the experimental data relevant for slow vector-meson propagation in nuclear matter. The s-...

Studies of meson production in nucleon–nucleon collisions at threshold are characterised by few degrees of freedom in a configuration of well defined initial and final states with a transition governed by short range dynamics. Effects from low–energy scattering in the exit channel are inherent to the data and probe the interaction in baryon–meson and meson–meson systems otherwise difficult to a...

An exposition is made of recent developments using techniques of unitary chiral perturbation theory, UχPT , which allows one to extend predictions using chiral Lagrangians to higher energies than ordinary chiral perturbation theory, including the region of low lying mesonic and baryonic resonances, some of which are dynamically generated in the approach. Results for meson meson scattering, pion...

We discuss the importance of the background in order to understand the scattering in the J PC = 0 ++ low and intermediate energy region and in particular regarding the σ meson. In order to appreciate better its importance we compare with the ρ meson in the P-wave ππ scattering. We also point out that in present analyses of three-body heavy meson decays, like those of D + and B, the role of this...

Non-exotic scalar-meson resonances in S-wave meson-meson scattering are studied in the light of a unitarised Schrödinger model. The resulting poles in the scattering matrices, by analytical continuation into the complex-energy plane, are grouped into nonets of isoscalar, isodoublet, and isotriplet resonances. All singularities can be related to quark-antiquark confinement states, the light-quar...

We argue that the description of meson-nucleon dynamics based on the boson-exchange approach, is compatible with the description of the nucleon as a soliton in the nonrelativistic limit. Our arguments are based on an analysis of the meson-soliton form factor and the exact meson-soliton and soliton-soliton scattering amplitudes in the Sine-Gordon model.

We determine the mass and strength of the scalar meson from NN scattering data by renormalizing the One Boson Exchange Potential. This procedure provides a great insensitivity to the unknown short distance interaction making the vector mesons marginally important allowing for SU(3) couplings in the S0 channel. The scalar meson parameters are tightly constrained by low energy np. We discuss whet...

The results of a model for meson-meson scattering are studied. The model is shown to be capable of on the one hand reproducing the scattering data, while on the other hand a quark-antiquark confinement spectrum can be determined. It is concluded that adopting the model’s formulation of the transition matrix elements for data analysis , it may serve as a link between experiment and quenched latt...