Scalar nonet quarkonia and the scalar glueball: mixing and decays in an   effective chiral approach
  We study the strong and electromagnetic decay properties of scalar mesons above 1 GeV within a chiral approach. The scalar-isoscalar states are treated as mixed states of quarkonia and glueball configurations. A fit to the experimental mass and decay rates listed by the Particle Data group is performed to extract phenomenological constraints on the nature of the scalar resonances and to the issue of the glueball decays. A comparison to other experimental results and to other theoretical approaches in the scalar meson sector is discussed. 
F. Giacosa, Th. Gutsche, V. E. Lyubovitskij and Amand Faessler