Renormalization schemes for mixing angles in extended Higgs sectors

TL;DR

This paper investigates various renormalization schemes for mixing angles in extended Higgs models, comparing their theoretical properties and calculating electroweak corrections to Higgs decays to improve precision in these theories.

Contribution

It introduces and compares new renormalization schemes based on observables and symmetry principles for mixing angles in extended Higgs sectors, including specific conditions for 2HDM and Higgs-Singlet models.

Findings

Renormalization schemes based on observables and symmetries are viable alternatives to $ar{MS}$.

Electroweak corrections to Higgs decays vary depending on the chosen scheme.

Certain schemes show improved gauge invariance and stability in calculations.

Abstract

The proper renormalization of mixing angles in quantum field theories is a long-standing problem. It is relevant for the renormalization of the quark mixing matrix in the Standard Model and for various mixing scenarios in theories beyond. In this contribution we specifically consider theories with extended scalar sectors. We describe renormalization schemes for mixing angles based on combinations of observables or symmetry requirements such as rigid or background-field gauge invariance and compare their properties to previous approaches such as $\bar{MS}$ schemes. We formulate specific renormalization conditions for the mixing angles in the Two-Higgs-Doublet Model and the Higgs-Singlet Extension of the Standard Model and calculate electroweak corrections to Higgs-boson decays via W- or Z-boson pairs within these models for a selection of (new and old) renormalization schemes.