Global Analysis of the Higgs Candidate with Mass ~ 125 GeV

TL;DR

The paper tests whether the 125 GeV Higgs candidate behaves like the Standard Model Higgs by performing a global fit to its couplings using a two-parameter framework for vector bosons (a) and fermions (c) and a generalized mass-scaling description (ε,M). It combines Tevatron, CMS, and ATLAS data and also maps composite Higgs scenarios (pseudo-dilaton, MCHM4, MCHM5) onto the same parameter space. The results show SM-like couplings are consistent within uncertainties and that the data prefer mass-proportional scaling (ε≈0, M≈v); several non-SM scenarios are disfavoured unless they closely mimic the SM. Overall, the analysis demonstrates that the Higgs candidate walks and quacks like the SM Higgs, with current data constraining potential deviations to the ~20% level and pointing toward future improved precision.

Abstract

We analyze the properties of the Higgs candidate with mass ~ 125 GeV discovered by the CMS and ATLAS Collaborations, constraining the possible deviations of its couplings from those of a Standard Model Higgs boson. The CMS, ATLAS and Tevatron data are compatible with Standard Model couplings to massive gauge bosons and fermions, and disfavour several types of composite Higgs models unless their couplings resemble those in the Standard Model. We show that the couplings of the Higgs candidate are consistent with a linear dependence on particle masses, scaled by the electroweak scale ~ 246 GeV, the power law and the mass scale both having uncertainties ~ 20%.

Figures (9)

• Figure 1: The constraints on the couplings $(a, c)$ of the Higgs candidate $h$ with mass $\sim 125$ GeV obtained from our global analysis of the available CMS, ATLAS, CDF and D0 data. The Standard Model is represented by a black star, and the yellow lines represent various composite Higgs models described in the text, which are disfavoured if they deviate strongly from the Standard Model.
• Figure 2: Marginalized one-dimensional projections on (left) the $a$ and (right) the $c$ axes of the likelihood function for our global fit result shown in Fig \ref{['fig:ac2']}.
• Figure 3: The constraints on the scaling parameters $(\epsilon, M)$ of the Higgs candidate $h$ with mass $\sim 125$ GeV obtained from our global analysis of the available CMS, ATLAS, CDF and D0 data. The Standard Model corresponds to the intersection of the yellow cross-hairs. The data are close to the 'bull's eye'.
• Figure 4: Marginalized one-dimensional projections on (left) the $\epsilon$ and (right) $M$ axes of the likelihood function for our global fit result shown in Fig \ref{['fig:epsilonM2']}.
• Figure 5: The mass dependence of the $h$ couplings found in our $(\epsilon, M)$ fit. The vertical error bars correspond to the uncertainties shown in Fig. \ref{['fig:epsilonM1']}. The dashed line is our best fit, and the dotted lines correspond to $\pm 1 \sigma$ variations in $(\epsilon, M)$. The Standard Model prediction that Higgs couplings should be proportional to the masses of other particles with $M = v$, shown by the diagonal solid red line, is completely consistent with the data.