Anomalous mass dependence of glueball exclusive decay rates

Exclusive decays such as G->ππ are studied in the framework of perturbative QCD. We discuss the possibility of the constituent gluons' virtualness scaling as the glueball mass Msub(G), which is a picture equivalent to a glueball containing a few slow-moving, heavy gluons. In this case, the decay rate exhibits a pinch singularity which enhances it by a factor of order (Msub(G)2/msub(q)2)2 over the dimensional scaling expectation. This singularity is partially suppressed by Sudakov effects which reduce the enhancement factor to (Msub(G)2/msub(q)2)sup(2n), where n approx.= 0.4. (orig.)