Which scalar meson is the glue-state ?
  Preliminary results of a work in collaboration with M.R. Pennington are presented. Extending a scheme introduced by Tornqvist, we investigate a dynamical model in which the spectrum of scalar mesons can be derived, with the aim of locating the lightest glue-state. Adding hadronic interaction contributions to the bare propagator, to `dress' the bare quark-model $q \overline q$ states, we are able to write the amplitudes and the phase shifts in the approximation in which scalar resonances decay only into two pseudoscalar channels. The fit of these quantities to experimental data gives a satisfactory understanding of how hadronic interactions modify the underlying `bare' spectrum. In particular, we examine the case in which a glue-state is introduced into the model. 
M. Boglione