ANOMALOUS FERMION MASS GENERATION AT THREE LOOPS.

We present a novel mechanism for generating fermion masses through global anomalies at the three-loop level. In a gauge theory, global anomalies are triggered by the possible existence of scalar or pseudoscalar states and heavy fermions, whose masses may not necessarily result from spontaneous symmetry breaking. The implications of this mass-generating mechanism for model building are discussed, including the possibility of creating low-scale fermion masses by quantum gravity effects. [ABSTRACT FROM AUTHOR]