Towards the Ultimate SM Fit to Close in on Higgs Physics

TL;DR

This paper performs a comprehensive, model-independent analysis of potential beyond the Standard Model effects in Higgs physics using dimension-six operators, identifying which deviations are still allowed by current data.

Contribution

It provides independent bounds on Wilson coefficients of dimension-six operators, clarifying where BSM effects could still manifest in Higgs observables.

Findings

Deviations in h->Vff distributions are constrained by existing data.

Triple gauge-boson couplings relate to certain Higgs decay deviations.

Large deviations in h->Z+gamma remain possible.

Abstract

With the discovery of the Higgs at the LHC, experiments have finally addressed all aspects of the Standard Model (SM). At this stage, it is important to understand which windows for beyond the SM (BSM) physics are still open, and which are instead tightly closed. We address this question by parametrizing BSM effects with dimension-six operators and performing a global fit to the SM. We separate operators into different groups constrained at different levels, and provide independent bounds on their Wilson coefficients taking into account only the relevant experiments. Our analysis allows to assert in a model-independent way where BSM effects can appear in Higgs physics. In particular, we show that deviations from the SM in the differential distributions of h->Vff are related to other observables, such as triple gauge-boson couplings, and are then already constrained by present data. On the contrary, BR(h-> Z+gamma) can still hide large deviations from the SM.