Dilepton production in pp and CC collisions with HADES

Fröhlich, I.; Agakishiev, G.; Agodi, C.; Balanda, A.; Bellia, G.; Belver, D.; Belyaev, A.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Braun Munzinger, P.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, Marco Giovanni; Dıaz, J.; Dohrmann, F.; Eberl, T.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P. J. R.; Friese, J.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gilardi, C.; Golubeva, M.; González Dıaz, D.; Grosse, E.; Guber, F.; Hadjivasiliou, C. H.; Heilmann, M.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Kozuch, A.; Krizek, F.; Krücken, R.; Kugler, A.; Kühn, W.; Kurepin, A.; Lamas Valverde, J.; Lang, S.; Lange, S.; Lopes, L.; Mangiarotti, A.; Marın, J.; Markert, J.; Metag, V.; Michalska, B.; Mishra, D.; Moriniere, E.; Mousa, J.; Müntz, C.; Naumann, L.; Novotny, R.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Pechenov, V.; Pechenova, O.; Pérez Cavalcanti, T.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Simon, R.; Spataro, Stefano Giovanni; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Veretenkin, I.; Wagner, V.; Wen, H.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Zanevsky, Y.; Zumbruch, P.

doi:10.1140/epja/i2006-10253-y

e(+) e(-) production was studied using the High Acceptance DiElectron Spectrometer (HADES). In pp collisions at 2.2GeV kinetic beam energy, the exclusive eta production and the Dalitz decay eta ->gamma e(+)e(-) have been reconstructed. The electromagnetic form factor of the latter decay was found to be in good agreement with the existing theoretical predictions. In addition, an inclusive e(+) e(-) invariant-mass spectrum from the C-12 + (12)(C) reaction at 2AGeV is presented and compared with a simplified thermal model.