Bayesian Model comparison of Higgs couplings

TL;DR

This paper uses Bayesian methods to analyze LHC data, assessing Higgs couplings and comparing the Standard Model with alternative models, finding strong support for the SM.

Contribution

It applies Bayesian inference and model comparison to Higgs coupling data, favoring simpler models and confirming compatibility with the Standard Model.

Findings

Good compatibility of Higgs couplings with SM

Models with fewer free parameters are preferred

Moderate to strong evidence supporting the SM

Abstract

We investigate the possibility of contributions from physics beyond the Standard Model (SM) to the Higgs couplings, in the light of the LHC data. The work is performed within an interim framework where the magnitude of the Higgs production and decay rates are rescaled though Higgs coupling scale factors. We perform Bayesian parameter inference on these scale factors, concluding that there is good compatibility with the SM. Furthermore, we carry out Bayesian model comparison on all models where any combination of scale factors can differ from their SM values and find that typically models with fewer free couplings are strongly favoured. We consider the evidence that each coupling individually equals the SM value, making the minimal assumptions on the other couplings. Finally, we make a comparison of the SM against a single "not-SM" model, and find that there is moderate to strong evidence for the SM.