Dynamics in the conformal window in QCD-like theories

The dynamics with an infrared stable fixed point in the conformal window in QCD-like theories (with a relatively large number of fermion flavors) is studied. The dependence of masses of colorless bound states on a bare fermion mass is described. In particular it is shown that in such dynamics glueballs are much lighter than bound states composed of fermions, if the value of the infrared fixed point is not too large. This yields a clear signature for the conformal window, which in particular can be useful for lattice computer simulations of these gauge theories. [S0556-2821(99)04408-2].