Unity of forces at the preon level with new gauge symmetries

Abstract

In the context of a viable, supersymmetric,preon model,it has been shown by Babu and Pati that the unity of forces can well occur at the level of preons near the Planck scale.This preonic approach to unification is explored further in this note with the inclusion of threshold effects which arise due to spreading of masses near the scale of suppersymmetry ($M_S=1$ TeV) and the metacolor scale (${\Lambda}_M=10^11$ GeV).These effects,which were ignored in the earlier work,are found to have marked consequences on the running and unification of relevant couplings leading to new possibilities for flavor-color as well as metacolor gauge symmetries.In particular, allowing for seemingly reasonable threshold effects,it is found that the metacolor gauge symmetry,$G_M$ is either $SU(6)_M$ or $SU(4)_M$ (rather than $SU(5)_M$) and the corresponding flavor-color gauge symmetry is either $SU(2)_LXU(1)_RXSU(4)_C$ (for $G_M=SU(6)_M$) or even just the standard model symmetry $SU(2)_LXU(1)_YXSU(3)_C$ (for $G_M=SU(6)_M or SU(4)_M$). Prospects of other preonic gauge symmetries are also investigated.