Related papers: A unitary model for meson-nucleon scattering
A simultaneous analysis (in the model-independent approach) of the $\pi\pi$ scattering (from the threshold to 1.9 GeV) and of the $\pi\pi\to K\overline{K}$ process (from the threshold to $\sim$ 1.46 GeV) is carried out in channel with…
We extract K-matrix poles from our fits to elastic pion-nucleon scattering and eta-nucleon production data in order to test a recently proposed method for the determination of resonance properties, based on the trace of the K-matrix. We…
The contribution of mesonic exchange currents to nuclear Compton scattering is investigated within the framework of a Fermi gas model of nuclear matter in the non-relativistic limit. The additional interaction between the nucleons is…
Radiative capture of the K-minus by the deuteron as a reaction for measurement of the Lambda-neutron scattering lengths. The use of spin information to separate the singlet and triplet scattering lengths is treated.
Effective Lagrangians suitable for a relativistic Hartree-Fock description of nuclear systems are presented. They include the 4 effective mesons $\sigma, \omega, \rho$ and $\pi$ with density-dependent meson-nucleon couplings. The criteria…
The separation of background and resonance contributions in pion-nucleon scattering is an often discussed issue. We investigate to what extent the background can be separated from the pole contribution. For illustration we use results from…
We report the chiral quark model approach for the study of baryon resonances in meson photoproduction and meson-nucleon scattering processes. Focussing on the $\pi N$ and $K N$ scatterings, we show that the cross sections near threshold can…
The capture of K$^-$ mesons on nucleons bound in nuclei offer a chance to study the $\Sigma \pi$ pairs below the kinematic threshold of the $\bar{\mathrm{K}}$N systems. Various hyperon-pion charged combination are presently under…
We discuss the possibility of constructing an effective gauge field theory of the nucleon interations based on the ideas of isotopic invariance as well as hypercharge invariance as a local gauge symmetry and spontaneous breaking of this…
The production of single photons in low energy (~1 GeV) neutrino scattering off nucleons is analyzed in the Standard Model. At very low energies, E(nu) << 1 GeV, a simple description of the chiral lagrangian involving baryons and arbitrary…
A comprehensive analysis of all available data on cross sections and spin-dependent observables for the $\gamma p \to K^+ \Sigma^0(1385)$, $\gamma n \to K^+ \Sigma^-(1385)$, and $\pi^+ p \to K^+ \Sigma^+(1385)$ reactions is performed within…
We investigate the $K^- p \to \gamma \Sigma$ reaction using an effective Lagrangian approach within an isobar model framework. The model includes contributions from $s$-channel hyperon and hyperon resonance, $t$-channel $K$ and $K^*$,…
Nucleon resonance information is often obtained from fitting hadrodynamical model calculations to data, where model parameters such as resonance coupling constants are the free parameters in the fitting procedure. For reactions with a…
By means of a coupled channel non-perturbative unitary approach, it is possible to extend the strong constrains of Chiral Perturbation Theory to higher energies. In particular, it is possible to reproduce the lowest lying resonances in…
We investigate the $\Lambda(1520)$ photoproduction in the $\vec{\gamma} p \to K^+ \Lambda(1520)$ reaction within the effective Lagrangian method near threshold. In addition to the "background" contributions from the contact, $t-$channel $K$…
We present a detailed analysis of S-wave Kpi scattering up to 2 GeV, making use of the resonance chiral Lagrangian predictions together with a suitable unitarisation method. Our approach incorporates known theoretical constraints at low and…
The branching ratios of K^- absorption at rest in nuclear matter are evaluated from the K^- self-energy by using the chiral unitary approach for the s-wave \bar{K} N amplitude. We find that both the mesonic and non-mesonic absorption…
The complete spectrum of states in the supersymmetric principal chiral model based on SU(n) is conjectured, and an exact factorizable S-matrix is proposed to describe scattering amongst these states. The SU(n)_L*SU(n)_R symmetry of the…
Motivated by the $1/N_c$ expansion, we study a simple model in which the pi-K scattering amplitude is the sum of a current-algebra contact term and resonance pole exchanges. This phenomenological model is crossing symmetric and, when a…
We study meson-baryon scattering with strangeness -1 in unitary chiral perturbation theory. Ten coupled channels are considered in our work, namely $\pi^0 \Lambda$, $\pi^0 \Sigma^0$, $\pi^- \Sigma^+$, $\pi^+ \Sigma^-$, $K^- p$, $\bar{K}^0…