Chiral Symmetry and Poincaré Invariance in Nuclei

Dan-Olof Riska

Helsinki Institute of Physics

An overview of the remarkable role of the "long range" pion mediated interactions in nuclei and baryons and their origin in the approximate chiral symmetry of QCD is given. The recent experimental discoveries of new heavy flavor hyperons have proven the phenomenological value of Skyrme's topological soliton model, which combines this "chiral dynamics" with heavy quark symmetry. Finally an overview is given of the possible ways to implement the requirement of Poincaré invariance in the models of nuclear and nucleon structure.