English

Fermion Traces Without Evanescence

High Energy Physics - Phenomenology 2020-02-12 v2

Abstract

We outline the evaluation of nn-dimensional fermion traces (nNn\in\mathbb{N}) built by products of Dirac-γ\gamma matrices suitable for a uniform dimensional continuation. Such a continuation is needed for calculations employing a dimensional regulator whenever intrinsically integer dimensional tensors yield non-vanishing contributions. A prime example for such a tensor is given by γ5\gamma_5 for n=4n=4. The main difference between Dimensional Regularization (DREG) and a Dimensionally Continued Regularization (DCREG) is that DCREG does not attempt to lift the algebra to continuous dd dimensions (dRd\in\mathbb{R}). As a consequence one has to properly deal with evanescent structures in order to ensure the uniform application of the regulator. In basic steps we identify evanescent structures in fermion traces and show that their proper treatment is crucial for example when calculating the VVAVVA anomaly in four dimensions. We checked that the performed considerations enable the evaluation of Standard Model (SM) ZZ-factors within DCREG up to including three loops.

Cite

@article{arxiv.1911.06345,
  title  = {Fermion Traces Without Evanescence},
  author = {Nikolai Zerf},
  journal= {arXiv preprint arXiv:1911.06345},
  year   = {2020}
}

Comments

33 pages, 3 figures, v2 journal version

R2 v1 2026-06-23T12:16:30.362Z