A Procedure g5anchor to Anchor in Feynman Diagrams for the Standard Model
Sep 12, 2024Citations per year
Abstract: (arXiv)
We present a procedure g5anchor to anchor in the definition of a Dirac trace with in Dimensional Regularization (DR) in Feynman diagrams for the Standard Model, based on a recent revision of the works by Kreimer, Gottlieb and Donohue. For each closed fermion chain with an odd number of primitive (i.e.~not-yet-clearly-defined) in a given Feynman diagram, g5anchor returns a definite set of anchor points for , in terms of pairs of ordered fermion propagators; at each of these anchor points a fixed expression in terms of the Levi-Civita tensor and elementary Dirac matrices will be inserted together with a sign determined by anticommutatively shifting all from their original places (dictated by the Feynman rules) to this anchor point. The defining expressions for the cyclic -odd Dirac traces in DR associated with closed fermion chains in amplitudes, or more generally squared amplitudes, thus follow from this procedure, where the Levi-Civita tensors are not necessarily treated strictly in 4-dimensions. We propose utilizing this definition in practical perturbative calculations in the Standard Model at least to three-loop orders with the current implementation, and maybe to higher loop orders in absence of Yukawa couplings to Higgs fields. Certain limitations and modifications of the KKS and/or the Kreimer scheme are addressed.Note:
- 45 pages
References(0)
Figures(11)
Loading ...