MESONIC DECAYS OF BARYON RESONANCES IN NUCLEI AND COMPRESSED HADRONICMATTER

As any composite, complex system the nucleon exhibits a rich excitatio n energy spectrum. The structure of these excitations - often called r esonances because of their large decay widths - can be studied in pi-i nduced and photonuclear reactions. In experiments at the electron acce lerator MAMI mesonic decays of free resonances and of resonances bound in complex nuclei have been studied with the photon spectrometer TAPS . By comparing free to bound resonances, one is sensitive to possible modifications of baryon properties within the surrounding nuclear envi ronment. An ensemble of mutually interacting baryon resonances can be generated in the central zone of relatvistic heavy ion collisions as d emonstrated in systematic studies of meson production at the heavy ion synchrotron SIS, utilizing TAPS and other detector systems.