Gauge-independent Renormalization of the 2-Higgs-Doublet Model

TL;DR

This paper develops a gauge-independent renormalization scheme for the 2-Higgs-Doublet Model, enabling precise higher-order predictions of Higgs observables crucial for experimental analysis and model differentiation.

Contribution

It introduces a process-independent, gauge-independent, and numerically stable renormalization scheme for the 2HDM, focusing on the critical mixing angles and their impact on Higgs observables.

Findings

The new scheme improves the stability of higher-order corrections.

It ensures gauge independence in the renormalization process.

The scheme is applicable to key Higgs decay processes.

Abstract

The 2-Higgs-Doublet Model (2HDM) belongs to the simplest extensions of the Standard Model (SM) Higgs sector that are in accordance with theoretical and experimental constraints. In order to be able to properly investigate the experimental Higgs data and, in the long term to distinguish between possible models beyond the SM, precise predictions for the Higgs boson observables have to be made available on the theory side. This requires the inclusion of the higher order corrections. In this work, we investigate in detail the renormalization of the 2HDM, a pre-requisite for the computation of higher order corrections. We pay particular attention to the renormalization of the mixing angles $\alpha$ and $\beta$, which diagonalize the Higgs mass matrices and which enter all Higgs observables. The implications of various renormalization schemes in next-to-leading order corrections to the sample processes $H^\pm \to W^\pm h/H$ and $H \to ZZ$ are investigated. Based on our findings, we will present a renormalization scheme that is at the same time process independent, gauge independent and numerically stable.