The universal Higgs fit

TL;DR

This paper introduces the universal Higgs fit, a global, model-independent framework that condenses Higgs-rate data from LHC and Tevatron into a first-order perturbative form around Standard Model predictions, enabling rapid testing of a wide range of beyond-SM scenarios. By extracting Higgs production cross sections, couplings, and invisible widths, the authors show the data cluster near SM expectations and provide a practical Gaussian-based representation of deviations through parameters $r_i$ and $\epsilon_i$. They apply the framework to composite Higgs models, 2HDMs, SUSY, dilaton scenarios, loop-induced effects, and DM portals, consistently finding that current data prefer the SM Higgs and disfavor alternatives like the pure dilaton, while constraining new physics in both tree-level and loop processes. Overall, the universal fit proves to be a powerful, adaptable tool for interpreting Higgs data as more precise measurements become available, with direct implications for model-building and future collider analyses. The derived SM Higgs mass from rates, $M_h = 125.0 \pm 1.8$ GeV, aligns with peak-based determinations, reinforcing the SM Higgs interpretation and guiding subsequent precision studies.

Abstract

We perform a state-of-the-art global fit to all Higgs data. We synthesise them into a 'universal' form, which allows to easily test any desired model. We apply the proposed methodology to extract from data the Higgs branching ratios, production cross sections, couplings and to analyse composite Higgs models, models with extra Higgs doublets, supersymmetry, extra particles in the loops, anomalous top couplings, invisible Higgs decay into Dark Matter. Best fit regions lie around the Standard Model predictions and are well approximated by our 'universal' fit. Latest data exclude the dilaton as an alternative to the Higgs, and disfavour fits with negative Yukawa couplings. We derive for the first time the SM Higgs boson mass from the measured rates, rather than from the peak positions, obtaining $M_h = 125.0 \pm 1.8$ GeV.

Figures (9)

• Figure 1: Measured Higgs boson rates at ATLAS, CMS, CDF, D0 and their average (horizontal gray band at $\pm1\sigma$). Here 0 (red line) corresponds to no Higgs boson, 1 (green line) to the SM Higgs boson (including the latest data point, which describes the invisible Higgs rate).
• Figure 2: $\chi^2$ as function of the model-independent Higgs couplings $r_i$ to the various SM particles, varying them one-by-one (the others are set to unity).
• Figure 3: Left: reconstruction of the Higgs production cross sections in units of the SM prediction. Right: reconstruction of the Higgs couplings to the $t,Z,W,b,\tau$, assuming that no new particles exist. The SM predicts a proportionality between the Higgs couplings and the masses of the fermions and the squared masses of the vector bosons (diagonal line).
• Figure 4: Left: fit of the Higgs boson couplings assuming common rescaling factors $a$ and $c$ with respect to the SM prediction for couplings to vector bosons and fermions, respectively. The two sets of contour lines are our full fit (continuous) and our approximated 'universal' fit (dotted). Middle: $1\sigma$ bands preferred by the three independent overall rates within the model. Right: values of the $\chi^2$ along the trajectories in the $(a,c)$ plane shown in the left panel, and given by $a=\sqrt{1-\xi}$ and $c=a$ (magenta) $c=(1-2\xi)/a$ (blue) $c=(1-3\xi)/a$ (red), as motivated by composite Higgs models models. The black dashed curve corresponds to $a=1$ and $c=1-\xi$.
• Figure 5: Left: fit for the Higgs boson branching fraction to photons and gluons, with $1$ and $2 \sigma$ contours. The dashed curves shows the possible effect of extra scalar partners of the top (red), of the bottom (blue), of the tau (black). Dotted lines show the Gaussian approximation. Right: Upper bound at $90\%$ (solid) and $99\%$ (dashed) C.L. on the new scalar coupling $r_S$ to the Higgs as a function of the new scalar mass $m_S$.