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HK: Fachverband Physik der Hadronen und Kerne

HK 27: Physik mit schweren Ionen

HK 27.8: Talk

Tuesday, March 11, 2008, 13:15–13:30, 2E

Dielectron measurement in proton-proton interactions at beam energy 1.25 GeV with HADES — •Tetyana Galatyuk for the HADES collaboration — Gesellschaft für Schwerionenforschung mbH, Darmstadt, Germany

For a better understanding of the contribution of Δ Dalitz and NN bremsstrahlung to dielectron production in heavy ion collisions HADES has studied pp and dp interactions. We present our measurements of dielectron production in pp reactions at E_beam=1.25 GeV, i.e. below the η production threshold. The most abundant source above the π⁰ Dalitz region is expected to be Δ Dalitz. However, due to off-shell propagation of intermediate vector mesons, higher-lying baryonic resonances can as well contribute to the mass region below the vector-meson pole mass [1]. In order to separate Δ Dalitz and np bremsstrahlung we compare the dielectron yield observed in pp with the dp reaction measured at the same beam energy.

[1] K. Shekhter, C. Fuchs, PHYS. REV C 68, 014904 (2003)