In the energy domain of 1-2 GeV per nucleon, HADES has measured rare penetrating probes in C+C, Ar+KCl, pp, dp and pNb collisions. For the first time the electron pairs were reconstructed from quasi-free np sub-reactions by detecting the proton spectator from the deuteron breakup. The experimentally constrained NN reference spectrum was established. Our results demonstrate that the di-electron yield in C+C collisions can be explained as a superposition of independent NN collisions. On the other hand, a direct comparison of the NN reference spectrum with the e+e- invariant mass distribution measured in the heavier system Ar+KCl at 1.76 GeV/u shows an excess yield above the reference, which we attribute to radiation from resonance matter. Moreover, the combined measurement of di-electrons and strangeness in Ar+KCl collisions has provided further intriguing results which we are happy to discuss with you.
Hyperon Σ, Λ(1405), K0 and pion production have been studied in propon-proton collisions at 3.5 GeV. At lower beam energy one pion and two pion production have been investigated in proton-proton and proton-neutron collisions at 1.25 GeV. Total and differential cross section have been measured and are available for comparison with model predisctions inside HADES acceptance. Respective acceptance filteres are avalaible upon request.Whom to contact? Interested in di-electrons: Tetyana Galatyuk, Romain Holzmann Interested in strangeness/hadrons: Laura Fabbietti, Manuel Lorenz, Beatrice Ramstein Interested in reaction plane and global event characterisation: Christoph Blume, Pavel Tlusty