Physics of Extra Dimensions

This report is organized as follows: In chapter 1 an introduction to the Kaluza-Klein theory is presented including the very basic concepts on which the Kaluza-Klein picture and Brane-world scenarios are based. It is far from being a complete review, neither in topics covered nor in list of references, however it is meant to serve as a background material mainly for Chapter 4. In Chapter 2, the idea of warped extra dimensions and localization of matter fields on a hyperspace in 4 + d dimensions is reviewed with the help of some examples taken from the literature. Chapter 3 discusses some of the physical implications of theories with extra dimensions, mainly the modification of the Cosmological evolution of the Universe and the fast proton decay. The last part if this chapter contains an example of generating baryon number violation in theories with extra dimensions and low gravity scales. Chapter 4 is devoted to a solution to the hierarchy problem, where an understanding of a single source responsible to both electroweak symmetry breaking and standard model fermion chirality is provided. The references are listed according to the order in which they appear first in the text. Unfortunately, it was not possible to refer to all the interesting and important papers written in this subject due to the limitation of space and time allowed for writing and submitting this dessertation. Therefore, only "samples" of such contributions to the literature could be provided