Related papers: $2\pi$ production in the Giessen coupled-channel m…
A refined investigation on light flavor meson-baryon scatterings is performed using a dynamical coupled-channel approach, the J\"ulich-Bonn model, that respects unitartiy and analyticity constraints. The channel space of $\pi N$, $\pi…
We investigate the structure of the nucleon resonance N^*(1440) (Roper) within a coupled-channel meson exchange model for pion-nucleon scattering. The coupling to pipiN states is realized effectively by the coupling to the sigmaN, piDelta…
The $s-$wave meson-baryon scattering is analyzed for the strangeness S=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$. The…
We present a lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. The study is based on the PACS-CS ensemble of gauge configurations with…
Based on the recently proposed Roy-Steiner equations for pion-nucleon scattering, we derive a system of coupled integral equations for the pi pi --> N-bar N and K-bar K --> N-bar N S-waves. These equations take the form of a two-channel…
The reaction $\pi^{-}p \to \eta n$ is investigated within a dynamical coupled-channels model of meson production reactions in the nucleon resonance region. The meson baryon channels included are $\pi N$, $\eta N$, $\pi \Delta$, $\sigma N$,…
A meson-exchange piN model, previously constructed using three-dimensional reduction scheme of the Bethe-Salpeter equation for a model Lagrangian involving \pi, \eta, N, \Delta, rho, and \sigma fields, is extended to energies up to 2 GeV by…
We present a new model independent amplitude analysis of reaction pi(-)p->pi(-) pi(+)n measured at CERN at 17.2 GeV/c on polarized target using a Monte Carlo method for dipion mass 580-1080 MeV. The two solutions for measured moduli…
In this work we study the $\pi N$ scattering process within the Baryon Chiral Perturbation Theory framework in the covariant scheme of Extended-On-Mass-Shell (EOMS). We compare the description obtained in this scheme with the previously…
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…
We present a dispersive representation of the $\gamma N\rightarrow \pi N$ partial-wave amplitude based on unitarity and analyticity. In this representation, the right-hand-cut contribution responsible for $\pi N$ final-state-interaction…
We derive a method to calculate the multi-channel K matrix applicable to a broad class of models in which mesons linearly couple to the quark core. The method is used to calculate pion scattering amplitudes in the energy region of low-lying…
A dynamical coupled-channel model is presented for investigating the nucleon resonances in the meson production reactions induced by pions and photons. The model is based on an energy-independent Hamiltonian which is derived from a set of…
The elastic $\pi N$ scattering is investigated for the $I=3/2$ channel dominated by the $\Delta(1232)$ resonance at finite baryon density, employing the effective Lagrangian approach at the tree-level Born approximation. The quark-meson…
We present a determination of the pion-nucleon sigma-term based on a novel analysis of the $\pi N$ scattering amplitude in Lorentz covariant baryon chiral perturbation theory renormalized in the extended-on-mass-shell scheme. This…
The four-dimensional $NN-\pi NN$ equations are adapted to the case of scalar particles with a $\phi^2\sigma$ interaction Lagrangian, and solved for energies below the $\sigma$-production threshold. This is achieved in the approximation…
We investigate the two-body reaction $\pi^- p \to K^{0} \Lambda$ within the effective Lagrangian approach and the isobar model. In addition to the "background" contributions from $t$-channel $K^*$ exchange, $u$-channel $\Sigma(1192)$ and…
A dynamical approach is developed to predict the $\pi N$ scattering amplitudes starting with the constituent quark models. The first step is to apply a variational method to solve the three-quark bound state problem. The resulting wave…
We discuss a recent extraction of the $\pi N$ $\sigma$ term $\sigma_{\pi N}$ from a large-scale fit of pionic-atom strong-interaction data across the periodic table. The value thus derived, $\sigma_{\pi N}^{\rm FG}=57\pm 7$ MeV, is directly…
In this talk I summarize recently proposed mechanisms to understand pi pi scattering to 1 GeV in an effective chiral Lagrangian. The Lagrangian includes higher resonances in addition to pions consistently with the chiral symmetry. Iso-spin…