Precision calculations for h->WW/ZZ->4 fermions in the Two-Higgs-Doublet Model with PROPHECY4F

TL;DR

This paper provides precise NLO electroweak and QCD corrections for Higgs decays into four fermions within various Two-Higgs-Doublet Models, highlighting the importance of renormalization schemes and their impact on decay width predictions.

Contribution

It presents the first detailed NLO calculations for h -> 4f decays in 2HDMs across different schemes, implemented in the PROPHECY4F generator.

Findings

Corrections are sensitive to renormalization scheme choices.

Differential distributions show constant offsets, not distinguishing 2HDMs from the SM.

Decay widths are largely unaffected by the specific 2HDM type.

Abstract

We have calculated the next-to-leading-order electroweak and QCD corrections to the decay processes h -> WW/ZZ -> 4 fermions of the light CP-even Higgs boson h of various types of Two-Higgs-Doublet Models (Types I and II, "lepton-specific" and "flipped" models). The input parameters are defined in four different renormalization schemes, where parameters that are not directly accessible by experiments are defined in the MSbar scheme. Numerical results are presented for the corrections to partial decay widths for various benchmark scenarios previously motivated in the literature, where we investigate the dependence on the MSbar renormalization scale and on the choice of the renormalization scheme in detail. We find that it is crucial to be precise with these issues in parameter analyses, since parameter conversions between different schemes can involve sizeable or large corrections, especially in scenarios that are close to experimental exclusion limits or theoretical bounds. It even turns out that some renormalization schemes are not applicable in specific regions of parameter space. Our investigation of differential distributions shows that corrections beyond the Standard Model are mostly constant offsets induced by the mixing between the light and heavy CP-even Higgs bosons, so that differential analyses of h -> 4f decay observables do not help to identify Two-Higgs-Doublet Models. Moreover, the decay widths do not significantly depend on the specific type of those models. The calculations are implemented in the public Monte Carlo generator PROPHECY4F and ready for application.