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.