Probing dense and hot matter with low-mass di-leptons and photons
Abstract.Results on low-mass di-leptons, covering the very broad energy range from the BEVALAC up to the SPS, are reviewed. The emphasis is on the open questions raised by the intriguing results obtained so far and the prospects for addressing them in the near future with the second generation of experiments, in particular HADES, NA60 and PHENIX.