Efeito Casimir, espalhamento de mésons e correções radioativas em uma eletrodinâmica escalar estendida: aspectos de temperatura finita

Abstract

In this thesis we investigate zero and finite temperature effects on a Lorentz-violating scalar electrodynamics of the Standard-Model Extension. At first, we calculate the thermal cross section for the scattering of distinct mesons at finite temperature through the Thermal Field Dynamics formalism, where we show that the induced temperature corrections are extremely large. In particular, we also show that the cross section appears to be only affected by the component of the violation coefficient in the propagation direction of the initial mesons. Next, we compute the one-loop corrections to the self-energy of the gauge field at finite temperature by using the Matsubara formalism. We focus on both CPT-even and CPT-odd contributions and we use the dimensional regularization technique. Specially, we show that the temperaturedependent parts do not have singularities and discuss how Furry’s theorem is broken with the presence of non-zero temperature. Subsequently, we investigate how the Casimir energy at zero temperature is modified by the CPT-even sector of extended scalar electrodynamics, where through a tensor parameterization we were able to investigate different configurations of the model: isotropic, anisotropic parity-even and anisotropic parity-odd. We show that although the net effect of Lorentz symmetry violation is very small, they tend to decrease or increase the Casimir energy depending on the configuration in which the system is found.