Confinamento de partículas bosônicas e superpartículas teste em modelos de mundo brana

Abstract

In this thesis we study the confinement of bosonic and spinning test particles in smooth Randall-Sundrum models. For this, we show that it is possible to find an effective potential hat describes the motion of the particle over the extra dimension. For the bosonic case, it is a known fact that free test particles {can be localized neither on thin nor on thick branes. Recently, a coupling to a scalar field has been used to localize a limited range of masses. Up to now, no mechanism has been found that can trap test particles of any mass over the brane. To solve this, we show that a coupling with the dilaton can trap particles of any mass. Next, we analyze the spinning particle. The spin variables, $\psi^{P}$, introduces an interaction with the Riemann curvature tensor. This introduces a correction to the effective potential. By analyzing it, we find that the spinning particle can be localized at a position different of that of the brane. We also show that a spinning particle over the brane can escape to infinity. Therefore, we can conclude that free bosonic and spinning particles are not trapped in the brane.