GAUGE INVARIANCE OF ELEMENTARY PARTICLE PROCESSES IN THE PRESENCE OF A BACKGROUND MAGNETIC FIELD

Elementary particle scatterings and decays in the presence of a background magnetic field are very common in physics, especially after the observation that the core of the neutron stars can sustain a magnetic field of the order of 1013 G. The important point about these calculations is that they are done in a background of a gauge field and as a result the calculations are prone to gauge arbitrariness. In this work we will investigate how this gauge arbitrariness is eradicated in processes where the initial and final particles taking part in the interactions are electrically neutral. Some comments on those processes where the initial or final state consists of electrically charged particles is presented at the end of the paper.

Electrodynamic metaphors: communicating particle physics with Feynman diagrams

The aim of this project is to communicate the basic laws of particle physics with Feynman diagrams - visual tools which represent elementary particle processes. They were originally developed as a code to be used by physicists and are still used today for calculations and elaborations of theoretical nature. The technical and mathematical rules of Feynman diagrams are obviously the exclusive concern of physicists, but on a pictorial level they can help to popularize many concepts, ranging from matter and the antimatter; the creation, destruction and transformation of particles; the role of "virtual" particles in interactions; the conservation laws, symmetries, etc.