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Dielectron production in reactions $pi^- p rightarrow n e^+e^-$ and $pi^- p rightarrow n e^+e^- gamma$ at energies less than 1 GeV is studied assuming electron-positron pair production to occur in the virtual time-like photon splitting process. Theoretical predictions of the effective mass distribution of dielectrons and their angular dependence are presented. Extraction of the electromagnetic form factor of baryon transition in the time-like region from future experiments of the HADES Collaboration is discussed.
Dielectron production in the $pi N$ interaction at not large energies is studied. The dominant contribution of the $Delta$-isobar creation in the intermediate state at incident pion momenta of about 0.3-0.4 GeV$/$c is shown. The experimental distribu
New precise experimental information on $sigma_{tot}(e^+e^- to pi^+ pi^-)$ is transferred into the space-like region, by taking advantage of the analyticity. As a result a rigorous pion electromagnetic form factor behavior is obtained. The latter with some existing model predictions is compared.
Recent BaBaR data on the pion transition form factor, whose Q^2 dependence is much steeper then predicted by asymptotic Quantum Chromodynamics (QCD), have caused a renewed interest in its theoretical description. We present here a formalism based on
The possibility to compute nucleon electromagnetic form factors in the time-like region by analytic continuation of their space-like expressions has been explored in the framework of the Skyrme model. We have developed a procedure to solve analytical
It has been pointed out that the recent BaBar data on the pi gamma^* -> gamma transition form factor F_{pi gamma}(Q^2) at low (high) momentum transfer squared Q^2 indicate an asymptotic (flat) pion distribution amplitude. These seemingly contradictor