Dilepton Production in Elementary Processes on the Nucleon

We study elementary processes for production of dileptons from nucleons, either through NN bremsstrahlung or through photon-induced reactions. We emphasize the dependence of the expected cross-sections on the electromagnetic formfactor of the nucleon in the time-like regime and point out that the mentioned reactions can provide important information on the validity of vector meson dominance for the nucleon. We also study the off-shell dependence of the formfactors.Comment: Figures available from author by fa

Electroproduction of hadrons on nuclei at GeV energies

We investigate coherence length effects and hadron attenuation in lepton scattering off nuclei in the kinematic regime of the HERMES experiment. The elementary electron-nucleon interaction is described within the event generator PYTHIA while a full coupled-channel treatment of the final state interactions is included by means of a BUU transport model. The results of our calculations are in good agreement with the experimentally measured transparency ratio of incoherent rho0 electroproduction off Nitrogen and the multiplicity ratio R_M^h for charged hadrons, pions, kaons, protons and anti-protons in deep inelastic scattering off Nitrogen and Krypton targets.Comment: 17 pages, 4 figures. Proceedings of 2nd Int. Conf. on Nuclear and Particle Physics with CEBAF at Jefferson Lab, Dubrovnik, 26-31 May 2003, to be published in Fizika

Vector Mesons and Baryon Resonances in Nuclear Matter

We calculate the effect of many-body interactions in nuclear matter on the spectral function of $\rho$ and $\omega$ meson. In particular, we focus on the role played by baryon resonances in this context.Comment: 4 pages, 4 figures, to be published in proceedings of the Third International Conference on Perspectives on Hadronic Physics, 7 - 11 May 2001, Miramare-Trieste, Ital