2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82752The observable consequences of a lowering of the restmasses of vector mesons on dilepton spectra in the SIS energy regime (HADES) and on photoabsorption cross sections on nuclei are studied in a transporttheoretical framework. We also investigate the consequences of a mass-shift of kaons in dense matter and compare with recent SIS data. The need for a detailed understanding of the elementary processes is underlined.10 pages, 4 figures. Proc. QCD Phase Transitions, Hirschegg 97Nuclear TheoryNuclear Experimenttext