Testing gauge-Yukawa-unified models by M

Abstract

Gauge-Yukawa Unification (GYU) is obtained in GUTs by searching for renormalization group invariant relations among gauge and Yukawa couplings beyond the unification scale. Of particular interest are two supersymmetric GUTs, the finite and the minimal SU (5) models. Both models provided us,among others,with predictions of the top quark mass which so far have passed successfully the tests of progressively more accurate measurements.

Constraints on finite soft supersymmetry-breaking terms

“…Taking into account the new constraints an all-order finite SU(5) model has been constructed [4], which among others successfully predicted the bottom and the top quark masses [4,6]. The later is due to the Gauge-and-Yukawa-of-the-third-generation Unifi- [15] and has been revived [21] taking into account the recent data.…”

Constraints on Finite Soft Supersymmetry Breaking Terms

“…Thus, the idea of gauge-Yukawa unification (GYU) [4]- [6] relies not only on a symmetry principle, but also on the principle of reduction of couplings [7,8] (see also [9]). This principle is based on the existence of RGI relations among couplings, which do not necessarily result from a symmetry, but nevertheless preserve perturbative renormalizability or even finiteness.…”

Reduction of couplings in the MSSM

“…Grand Unified Theories (GUTs) which support SU(5) symmetry is an example of how to reduce three gauge couplings into a unified one. Besides this great achievement SU (5) GUT can also relate Yukawa couplings via the prediction of the ratio M τ /M b . However imposing larger symmetries seems not to help, because of the new degrees of freedom that are introduced.…”