UNIFICATION BEYOND GUTS - GAUGE-YUKAWA UNIFICATION

Gauge-Yukawa Unification (GYU) is a renormalization group invariant fu nctional relation among gauge and Yukawa couplings which holds beyond the unification point in Grand Unified Theories (GUTs). We present her e various models where GYU is obtained by requiring the principles of finiteness and reduction of couplings. We examine the consequences of these requirements for the low energy parameters, especially for the t op quark mass. The predictions are such that they clearly distinguish already GYU from ordinary GUTs. It is expected that it will be possibl e to discriminate among the various GYUs when more accurate measuremen ts of the top quark mass are available.