QCD Symmetries in $\eta $- and $\eta '$-Mesic Nuclei

Abstract

We discuss the role of QCD symmetries and confinement in understanding eta\nand etaprime mesic nuclei. Eta and etaprime bound states in nuclei are\nsensitive to the flavour-singlet component in the meson. The bigger the singlet\ncomponent, the more attraction and the greater the binding. Recent results on\nthe etaprime mass in nuclei from the CBELSA/TAPS collaboration are very similar\nto the prediction of the Quark Meson Coupling model. In the model eta-etaprime\nmixing induces a factor of two enhancement of the eta-nucleon scattering length\nrelative to the prediction with a pure octet eta, with real part about 0.8 fm.\n