Effet d'un défaut topologique sur les spectres des hadrons et confinement des quarks dans un espace-temps avec une métrique de type schwarzchild induite par un champ scalaire non gravitationnel

Abstract

In this thesis, we propose a new approach that combines the principles of quan tum mechanics and those of general relativity to study the properties of hadrons and the effects of space-time curvature on them. On the one hand, we analyze the effects of the gravitational field of a linear topological defect on the spectra of heavy quarkonia. The investigated particles are moving in a space-time curved by the presence of a cosmic string, whose metric is assumed to be torsion-free. The full spectrum of each particle is obtained by solving the radial Schr¨odinger equation with an extended version of the Cornell potential. On the other hand, we propose a purely geometric description of the strong interaction, in other words, one capable of affecting the structure of space-time. We use the approach proposed by Barros to study hadron spectra and few properties linked to the confinement of quarks and gluons in an Einstein-Schwarzchild type space time, whose metric is generated by a non-gravitational scalar field. The theoretical re sults of our model were used to calculate the mass spectra, decay constants and thermo dynamic properties of some mesons, the masses of some baryons and atomic nuclei as well as the confinement radius of some hadrons. The obtained results were compared with the available experimental data and the predictions from other relevant theoretical studies. In most considered cases, our predictions are in good agreement with the expe rimental data. It was observed that the role of topological parameter is very significant in this study. Indeed, its gravitational field acts on the mass levels in a manner analo gous to the Zeeman effect due to the magnetic field. Furthermore, from our numerical results, a simple explanation of color confinement was provided, based on black hole theory.