Chiral Symmetries in the Standard Model of Particle Physics and its Extensions

Abstract: Chiral gauge theories are a central focus of research in theoretical particle physics due to the parity symmetry breaking observed in the Standard Model. Left-Right Symmetric Models (LRM) explain the breaking of parity through a Spontaneous Symmetry Breaking Mechanism, predicting new $W_R$ and $Z_R$ gauge bosons. The absence of direct BSM physics detection at the LHC has driven research towards precision observables and Effective Field Theories (EFTs), particularly the SMEFT framework. Precision radiative calculations in chiral theories using dimensional regularization require a $D$-dimensional $γ_5$ prescription, such as the mathematically consistent Breitenlohner-Maison-'t Hooft-Veltman (BMHV) scheme. However, this scheme introduces gauge symmetry-breaking terms that obstruct Slavnov-Taylor identities. A primary objective of this thesis is to provide a pedagogical introduction to cancelling these spurious anomalies via algebraic renormalization, and to derive the one-loop symmetry-restoring finite counterterms required to renormalize the four-fermion operators of the $ν$SMEFT. Furthermore, the thesis explores UV completions like LRMs embedded in other BSM theories like the Grand Unified Theories. This embedding implies that no discrete symmetries remain at the TeV scale and allows LRMs to be treated as EFTs with the minimal scalar content needed to perform the Spontaneous Symmetry Breaking Mechanism. The second main objective is to derive robust lower bounds on the masses of the new gauge bosons and the LR scale using collider observables. This analysis is performed for both the effective and traditional LRMs, ensuring that the results are independent of other parameters of the theory.