New renormalization scheme in the two Higgs doublet models

TL;DR

This paper introduces a novel renormalization scheme for two Higgs doublet models that uses Higgs decay rates to determine mixing angles, improving the physical interpretability of these parameters compared to previous methods.

Contribution

The new scheme determines Higgs mixing angles via decay rates at NLO, maintaining their physical meaning and providing a more accurate framework than previous methods based on two-point functions.

Findings

The new scheme aligns Higgs decay predictions with SM at NLO.

It preserves the physical interpretation of the Higgs mixing angles.

Predictions differ from previous schemes, showing the impact of the new approach.

Abstract

We propose a new renormalization scheme in the two Higgs doublet models with a softly-broken $Z_2$ symmetry and CP-conservation in the Higgs sector. In this scheme, counterterms for mixing angles of the Higgs bosons are determined by using the decay rates of the discovered Higgs boson $h$, $i.e.$, $h \to \tau^+\tau^-$ and $h \to ZZ^* \to Z\ell^+\ell^-$ at next leading order (NLO) instead of using the renormalized two-point functions which are adopted in the previous scheme. We require that the decay rates at NLO are determined to be the corresponding predictions at NLO in the Standard Model (SM) times square of the scaling factor which describes the deviation of $h$ couplings at tree level from the SM value. The mixing angles then maintain the meaning of the ``alignmentness", $i.e.$, how the properties of $h$ are close to the SM predictions, while they lose such meaning in the previous scheme. We compare the predictions of the decay rates at NLO given in the new scheme and those in the previous scheme.