Symmetries in one loop solutions: The AV, AVV, and AVVV diagrams, from 2D, 4D, and 6D dimensions and the role of breaking integration linearity

TL;DR

This paper explores the role of surface terms and linearity breaking in fermionic amplitudes across various dimensions, revealing how symmetry violations are independent of divergences and can be managed through different regularization choices.

Contribution

It introduces an analysis of symmetry relations in fermionic amplitudes using Implicit Regularization, highlighting the impact of surface terms and the independence of symmetry violations from divergences.

Findings

Surface terms depend on finite amplitudes and affect symmetry.

Breaking linearity influences Ward identities and amplitude expressions.

Symmetry violations are independent of divergences and can be managed.

Abstract

We investigated relations among green functions defined in the context of an alternative strategy for coping with the divergences, also called Implicit Regularization. Our targets are fermionic amplitudes in even space-time dimensions, where anomalous tensors connect to finite amplitudes. Those tensors depend on surface terms, whose non-zero values arise from finite amplitudes as requirements of consistency with the linearity of integration and uniqueness. Maintaining these terms implies breaking momentum-space homogeneity and in a later step the Ward identities. Meanwhile, eliminating them allows more than one mathematical expression for the same amplitude. That is a consequence of choices related to the involved Dirac traces. Independently of divergences, it is impossible to satisfy all symmetry implications that require the vanishing of surface terms and linearity simultaneously. Nonetheless, the symmetry violations are globally independent of divergences and can be allocated appropriately. From this perspective, we cast all the choices involved and the different meanings, whose implications go beyond the scenario described.