Related papers: pp <-> pi+ d process at low energy: Interplay betw…
We analyze the new threshold data for neutral pion photoproduction off protons in the framework of heavy baryon chiral perturbation theory. We show that large loop corrections are needed to understand the S--wave multipole $E_{0+}$ and that…
A phenomenological calculation from threshold to 800 MeV of the initial proton beam energy is presented to describe recent data on the reaction pp --> (pp)_S-wave pi^0 with a low energy cut on the final state diproton excitation energy. A…
This work elaborates on former remarks of ours regarding two sets of predictions for the observables of the charge-exchange reaction $\pi^- p \to \pi^0 n$ at low energy (pion laboratory kinetic energy $T \leq 100$ MeV). The first prediction…
A dynamical model for S-- and P--wave correlated $2 \pi$ (and $K \bar K$) exchange between a kaon and a nucleon is presented, starting from corresponding $N \bar N \rightarrow K \bar K$ amplitudes in the pseudophysical region, which have…
In this talk we cover several issues concerning pion production. The first one is the p p ----> p p pi^0 reaction where an alternative explanation based on the off shell extrapolation of the pi N amplitude is offered. A recent model for the…
We construct a model for the weak pion production off the nucleon, which in addition to the weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$, it includes also some background terms required by chiral…
Total cross sections for the pp --> pp eta' reaction have been measured in the excess energy range from Q = 1.53 MeV to Q = 23.64 MeV. The experiment has been performed at the internal installation COSY-11 using a stochastically cooled…
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high degree of the polarized proton beam of COSY, the reaction pp{\to} pp{\eta} has been measured close to threshold to explore the analyzing…
A general algorithm for handling the energy dependence of hadron-nucleon amplitudes in the nuclear medium, consistently with their density dependence, has been recently applied to antikaons, eta mesons and pions interacting with nuclei.…
The pion-nucleon amplitude is considered in the vicinity of the elastic scattering threshold within a relativistic dynamical model dressing the pi N N and pi N Delta vertices self-consistently with an infinite number of meson loops. The…
The positively charged pions produced in proton-proton collisions at a beam momentum of 1640 MeV/c were measured in the forward direction with a high resolution magnetic spectrograph. The missing mass distribution shows the bound state…
Information about the production mechanism of the eta meson in proton-proton collisions can be inferred by confronting the experimental studies on the analysing power for the p(pol)p --> pp eta reaction with the theoretical predictions of…
The reactions p+n-->d+omega and p+n-->d+phi are studied within a relativistic meson-exchange model of hadronic interactions. Predictions for the total cross sections and for the angular distributions of the vector mesons are presented. The…
The charge changing weak production of Delta in nucleons and nuclei is studied. The reactions e^{-} p -> Delta^{0} \nu_{e} and e^{+} p -> Delta^{++} \bar{\nu}_{e} are considered as a possible source of information about the weak N-Delta…
We review the major progress of the past decade concerning our understanding of the nucleon-nucleon interaction. The focus is on the low-energy region (below pion production threshold), but a brief outlook towards higher energies is also…
The production of antiprotons in $pp$ collisions is investigated close to threshold where experimental data about the total cross section are not available. We analyze the latter reaction within the LUND string model for inclusive $\bar{p}$…
Short range meson-exchange mechanisms such as $\rho\to\omega\pi^0$ contribute significantly to the amplitude for $pp\rightarrow pp\pi^0$ near threshold in addition to pion rescattering. The uncertainty of the latter contribution, which…
Interactions of neutrinos with nuclei in the energy ranges relevant for the MiniBooNE, T2K, NO$\nu$A, MINER$\nu$A and MINOS experiments are discussed. It is stressed that any theoretical treatment must involve all the relevant reaction…
Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical model derived from an effective chiral Lagrangian. The…
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…