Study of elementary reactions with the hades dielectron spectrometer

Results obtained with the HADES dielectron spectrometer at GSI are discussed, with emphasis on dilepton production in elementary reactions. Díaz Medina, José, Jose.Diaz@uv.es ; Gil Ortiz, Alejandro, Alejandro.Gil@ific.uv.es

Deep sub-threshold $K^\ast (892)^{\circ}$ production in collisions of Ar + KCl at 1.76 A GeV

Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76A GeV

Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)0 are reported for collisions of Ar + KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)0 production probability per central collision of \( P_{K^{*0}}=(4.4\pm 1.1 \pm 0.5)\times 10^{-4}\) and the K*(892)0/K0 ratio of \( P_{K^{*0}}/P_{K^0}=(1.9\pm 0.5\pm 0.3)\times 10^{-2}\) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, \( \sqrt{s_{NN}}-\sqrt{s_{thr}}=-340\) MeV). The K*0/K0 ratio is compared with results of other experiments and with the pre…