Aspectos da eletrodinâmica quântica em dimensões espaciais extras

Abstract

An explicit evaluation of the pentadimensional Quantum Eletrodynamics (QED5) vacuum polarization tensor is presented. The calculations are made preserving all the intrinsic arbitrariness involved in such type of problem. The internal momenta are assumed arbitrary in order to preserve the possibility of dependence on such kind of choice. An arbitrary scale is introduced in the separation of terms having di¤erent degree of divergences in order to preserve the possibility of scale ambiguities. In the performed steps it is avoided the e¤ects of regularizations by using an adequate strategy to handle the problem of divergences in Quantum Field Theory perturbative calculations. Given this attitude it is possible to get clean and sound conclusions about the consistency requirements involved in perturbative calculations D=4+1 space-time dimension. At the final a symmetry preserving and ambiguities free result is obtained allowing the renormalization of the photon propagator at the one-loop level. The simplicity, added to the general character, of the adopted procedure, allows to believe that such a strategy can be used as an alternative to the traditional regularization procedures, in particular em situations where such methods present restrictions of aplicability or leds to not consistent results. The refered procedure does not possesse restrictions of applicability of any order and can be aplied in pertubative calculations associated to theories formulated in a space-time having extra dimensions relative to the physical one (D=3+1), producing consistent results, in odd and in even dimensions, in spite of the possible nonrenormalizable character of such theories.