Anomalia de escala e invariância de calibre em eletrodinâmica quântica: um estudo diagramático

• Ano de defesa: 2012
• Autor(a) principal: Joilson Silva Porto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Física
• Link de acesso: http://hdl.handle.net/1843/MPDZ-8XSGFU

Symmetry under dilatation appears at classical level should a Lagrangian be free of dimensionful constants. The Noether current associated to this symmetry is called dilatation current. Quantum symmetry breaking of dilation current (scaling anomaly) is related to the trace of the energy momentum tensor. For this reason it is also known as trace anomaly. In this work we calculate perturbatively, at one loop order, the trace anomaly of massless quantum electrodynamics. The purpose is to study the interplay between dilation and gauge Ward identities in connection with momentum routing invariance bearing in mind a similar analysis done for the Adler-Bardeen-Bell-Jackiw anomaly. We perform the calculations in a regularization independent fashion in order to exclude spurious anomalies.