Spectroscopy "windows" of quark-antiquark mesons and glueballs with   effective Regge trajectories
  Regge trajectories of quark-antiquark mesons can be well approximated for phenomenology purposes by a specific nonlinear form, reflecting that the flux tubes cannot be arbitrarily large, but break due to the effect of pair-production. If confirmed, this would imply that there is only a finite number of bound states on each trajectory, and consequently, an existence of ``spectroscopy windows'' for each flavor. Here we present our results for these windows. 
M.M. Brisudova, L. Burakovsky, T. Goldman