SMuK 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

T: Fachverband Teilchenphysik

T 84: Theory EW

T 84.6: Vortrag

Mittwoch, 22. März 2023, 18:45–19:00, HSZ/0204

Algebraic Renormalization of abelian chiral Gauge Theories with non-anticommuting γ₅ at the Multi-Loop Level — •Matthias Weißwange — Institut für Kern- und Teilchenphysik, TU Dresden, Dresden, Deutschland

Divergences emerging in quantum corrections need to be handled via regularization and renormalization. However, treating manifestly 4-dimensional quantities such as γ₅ and ε^µνρσ naively within dimensional regularization (DReg) may lead to inconsistencies. This constitutes a problem in chiral gauge theories, such as the electroweak Standard Model. In order to avoid such inconsistencies, γ₅ needs to be treated rigorously as a non-anticommuting object using the Breitenlohner-Maison/’t Hooft-Veltman (BMHV) scheme within DReg. Employing the BMHV scheme, however, violates gauge invariance, which subsequently needs to be restored using symmetry-restoring counterterms guaranteed to exist by the methods of algebraic renormalization. These counterterms may be calculated via special Feynman diagrams with an insertion of the Δ-operator, which reflects the breaking of chiral gauge invariance, using the regularized quantum action principle of DReg. In the case of an abelian chiral gauge theory this is consistently done at the multi-loop level, showing that the counterterm structure in the BMHV scheme may be written in a very compact form, suitable for computer implementations. Ultimately, this renormalization procedure will be needed for high-precision calculations of e.g. electroweak observables.