Abstract:
It is an intriguing possibility that our universe may consist of more than three spatial dimensions, compactified on such a small scale that they are so far have not seen (escaped detection). This compactification will lead to a tower of new particle states in the effective four dimensional theories. In this thesis, a particular realization of this idea the scenario of so-called universal extra dimensions (UED) is studied in some detail, with a focus on exploring the particle at high energy scales (the evolution of Yukawa couplings). We derived the renormalization group equations for the gauge and Yukawa couplings at one-loop level. It is found that the evolution of the gauge couplings has a rapid variation in the presence of the KK modes and this leads to a much lower unification scale than the SM. The running of Yukawa couplings for the three families has a sizable variation in five
dimensional models. We quantitatively discussed these quantities for
observing similar behaviors for all values of the compactification radius below these scale their trajectory run in the usual SM logarithmic fashion.
