Related papers: Pion electroproduction in a nonrelativistic theory
We investigate neutrino induced one pion production on nucleons. The elementary neutrino--nucleon cross section is calculated as the sum of the leading Delta pole diagram and several background diagrams obtained within the non-linear sigma…
We present a model of electron-positron pair production in pion-nucleon collisions in the exclusive reaction \pi N -> Ne^+e^-. The model is based on an effective field theory approach, incorporating 16 baryon resonances below 2 GeV.…
This work represents an extension of the single pion production model proposed by D. Rein. The model consists of resonant pion production and nonresonant background contributions coming from three Born diagrams in the helicity basis. The…
Photo- and electroproduction of pions and eta-mesons is studied on the nucleon. The formalism of such reactions is presented including polarization degrees of freedom and theoretical approaches are discussed. In particular, the threshold…
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…
Recent CLAS data on the $p\pi^+\pi^-$ electroproduction off protons at 1.3$<$W$<$1.57 GeV and 0.25$<$$Q^{2}$$<$0.6 GeV$^{2}$ have been analyzed using a meson-baryon phenomenological model. By fitting nine 1-fold differential cross section…
The reaction $NN \to NN \pi$ offers a good testing ground for chiral effective field theory at intermediate energies. It challenges our understanding of the first inelastic channel in nucleon-nucleon scattering and of the charge-symmetry…
Results of the recently developed unitary isobar model (MAID) are presented for the spin asymmetries, structure functions and relevant sum rules in the resonance region. The model describes the presently available data for single-pion…
A status report is given for the current theoretical understanding of pion production close to threshold. In the first part of the talk predictions of a meson exchange model are compared to recent polarized data for the reactions $pp \to…
In this paper we study coherent neutrinoproduction of photons [neutral current (NC)] and pions [charged current (CC) and NC] with $E_{\nu} \leqslant 0.5 $ GeV. The production from nucleons and incoherent production with $E_{\nu} \leqslant…
We investigate electroproduction of pion pairs on the nucleon in the framework of QCD factorization for hard exclusive processes. We extend previous analyses by taking the hard-scattering coefficients at next-to-leading order in $\alpha_s$.…
The double pion photoproduction off nucleons near threshold is analyzed in a covariant baryon chiral perturbation theory up to next to leading order, where the $\Delta(1232)$, $N^*(1400)$ and $\rho(770)$ resonances are included as explicit…
Chiral perturbation theory is the effective field theory of the standard model. In this talk, I discuss some applications of this framework to the pion--nucleon system. These are chiral corrections to the S--wave pion--nucleon scattering…
In the first part of the talk, I discussed the nature of the effective theory that describes the properties of the pion-nucleon-interaction at low energies, using the static model as a starting point. In the second part, I then pointed out…
We refine our previous calculation of multipole amplitude $E_{0+}$ for pion photoproduction process, $\gamma N\rightarrow\pi N$. The treatment of final-state interactions is based upon an earlier analysis of pion-nucleon scattering within…
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…
The study of the $\gamma^* N\rightarrow \Delta$ reaction presents the best quantitative method to explore the deviation of hadron shapes from spherical symmetry (nonspherical amplitudes). Significant non-spherical electric (E2) and Coulomb…
We discuss the extended on-mass-shell scheme for manifestly Lorentz-invariant baryon chiral perturbation theory. We present a calculation of pion photo- and electroproduction up to and including order $q^4$. The low-energy constants have…
Neutrino-induced productions (neutrinoproduction) of photons and pions from nucleons and nuclei are important for the interpretation of neutrino-oscillation experiments, as they are potential backgrounds in the MiniBooNE experiment [A. A.…
The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, and Nakayama [Phys. Rev. C 83, 065502 (2011)]. The hadronic final-state…