Related papers: Pion re-scattering in pi0 production near threshol…
We improve, in the energy region between $\bar{K}K$ threshold and $\sim~1.4$ GeV, the energy-dependent phase shift analysis of $\pi\pi$ scattering presented in a previous paper. For the S0 wave we have included more data above $\bar{K}K$…
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…
$pp\to pp\pi^0$ and $pp\to pp\eta$ were considered close to threshold. The pion production was found not only to be dominated by impulse approximation (IA) and rescattering contributions, but also strongly by box-diagrams, resonances and…
From recent charge exchange measurements in the extreme forward direction, an independent and precise determination of the pion nucleon coupling constant is possible. This determination has reopened the debate on the value of this…
Using the results presented in the talk by V.Vereshagin (this conference), we illustrate the approach developed in earlier papers by the calculation of (\pi N) elastic scattering amplitude and explain how to derive corresponding bootstrap…
A microscopic coupled-channels model for Compton and pion scattering off the nucleon is introduced which is applicable at the lowest energies (polarizabilities) as well as at GeV energies. To introduce the model first the conventional…
We present a new and improved model independent amplitude analysis of reactions $\pi^+ n_\uparrow \to \pi^+ \pi^- p$ at 5.98 and 11.85 GeV/c and $\pi^- p_\uparrow \to \pi^- \pi^+ n$ at 17.2 GeV/c measured with transversely polarized targets…
The elastic backward proton-deuteron scattering is analyzed within a covariant approach based on the Bethe-Salpeter equation with realistic meson-exchange interaction. Contributions of the one-nucleon and one-pion exchange mechanisms to the…
A non perturbative renormalization scheme for Nucleon-Nucleon interaction based on boundary conditions at short distances is presented and applied to the One Pion Exchange Potential. It is free of off-shell ambiguities and ultraviolet…
Large momentum transfer reactions such as pion production represent the frontier of Chiral Perturbation Theory and must be understood before more complex reactions can be considered. Pion production is also interesting in its own right, one…
We discuss transverse spin effects caused by the spin-flip part of the Pomeron coupling with the proton. The predicted spin asymmetries in proton-proton scattering and QQ production in proton-proton and lepton-proton reactions are not small…
We address the problem of pion production in low energy $\pi$-nucleus collisions. For the production mechanism we assume a simple model consisting of a coherent sum of single pion exchange and the excitation---followed by the decay into two…
The polarizabilities of light pseudoscalar mesons can be extracted from differential cross sections for Compton scattering near threshold. While this has been accomplished for charged pions employing Primakoff reactions, a corresponding…
A perturbative QCD treatment of the pion wave function is applied to computing the scattering amplitude for coherent high relative momentum di-jet production from a nucleon.
Using unitarized Chiral Perturbation Theory methods, we perform a detailed analysis of the $\pi\pi$ scattering poles $f_0(600)$ and $\rho(770)$ behaviour when medium effects such as temperature or density drive the system towards Chiral…
Central pseudoscalar production in $pp$ scattering is suppressed at small values of $Q_\perp$, where $Q$ is defined as the difference between the momenta transferred from the two protons. Such a behaviour is expected if the production…
Based on a counting scheme for the application of chiral perturbation theory to pion production in NN collisions p-wave production is studied. It is demonstrated that, contrary to the s-wave production where loops enter at too low an order…
We present a microscopic model for coherent pion production off nuclei induced by neutrinos. This model is built upon a model for single nucleon processes that goes beyond the usual Delta dominance by including non resonant background…
We consider the cross section of the deep inelastic pion electroproduction on a proton target at threshold for Q^2 in the region 5-10 GeV^2. The corresponding amplitudes are described in terms of two form factors which we calculate using…
The strong interaction shift $\epsilon$ and broadening {\Gamma} in pionic deuterium have been determined in a high statistics study of the {\pi}D(3p - 1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium…