Related papers: Pion axioproduction revisited
Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit $\Delta(1232)$ degrees of freedom up to…
A complete calculation of the pion-nucleon loops that contribute to the transition operator for $NN\to NN\pi$ up-to-and-including next-to-next-to-leading order (N$^2$LO) in chiral effective field theory near threshold is presented. The…
We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by the…
We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon, pion and contact terms are calculated using a chiral Lagrangian. The contribution of the Roper resonance, neglected in…
Exclusive measurements of the quasi-free $pn \to pp\pi^0\pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained…
As a result of a new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor, and due to the relevance of this form factor for neutrino induced coherent pion production, we re-evaluate our model…
In the framework of chiral effective field theory of delta resonances, nucleons and pions interacting with background gravitational field we calculate the gravitational form factors of the nucleon up to fourth order in the small scale…
A fit to the existing pion electroproduction data is presented. This work builds upon our previous analyses of pion photoproduction and elastic pion-nucleon scattering over the Delta resonance region. We comment on the extraction of E_1+…
We study the neutral pion photoproduction at near-threshold energies in fully covariant chiral perturbation theory up to O(p^3). When including only nucleonic virtual states in the model, the convergence is too slow. Therefore we test the…
In this present investigation, we explore the elastic scattering of pions with nuclei ($\pi$-$A$), primarily influenced by the $\Delta$(1232) resonance, within the Eikonal-Glauber model. The medium effects are incorporated by considering…
A combined analysis of the reactions $\pi^+p\to \pi^+p$, $\pi^-p\to \pi^-p$ and $\pi^-p\to \pi^0n$ is carried out with a chiral quark model. The observations are reasonably described from the $\Delta(1232)$ resonance region up to the…
The (\pi^{-}\Delta^{++}) production on the nucleon by real and virtual photons is discussed as initial step in a simple model approach for the two pion photo- and electroproduction on the nucleon, with emphasis on nucleon resonance…
Decays of baryon resonances in the second and the third resonance region into N pi0 pi0 are studied by photoproduction of two neutral pions off protons. Partial decay widths of N* and Delta* resonances decaying into Delta(1232) pi,…
Incoherent photoproduction of pions on the deuteron in the Delta(1232) resonance region is investigated in order to study the influence of final state NN and PiN rescattering. For the elementary production operator an effective Lagrangian…
We present some results on the analysis of three pion resonances. The analyses are motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. We construct reaction amplitudes…
The production of mesons in nucleon-nucleon collisions is reviewed from the viewpoint of the meson-exchange picture. In the first part various possible production mechanisms and their relative importance are discussed. In addition, general…
We have developed a model for the N N --> N N pi pi reaction and evaluated cross sections for the different charged channels. The low energy part of those channels where the pions can be in an isospin zero state is dominated by N*…
We study the imaginary parts of the isoscalar electromagnetic and isovector axial form factors of the nucleon close to the $3\pi$-threshold in covariant baryon chiral perturbation theory. At the two-loop level, the contributions arising…
Single pion production off nucleons is studied in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. Using total and some older differential cross section data to pin down the low-energy…
This PhD thesis is a first step towards the control of the quantum corrections in the Resonance Chiral Theory, the suggested framework to handle QCD in the resonance region. After a theoretical introduction, Chapter 3 is devoted to…