Combined measurements of Higgs boson couplings in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This CMS collaboration paper delivers a comprehensive combination of Higgs boson production, decay, and coupling measurements using 2016 data at √s = 13 TeV (35.9 fb^{-1}). By unifying analyses across ggH, VBF, VH, and ttH with decays to γγ, ZZ, WW, ττ, bb, μμ and including invisible decays, the study extracts a global signal strength μ = 1.17 ± 0.10 at m_H = 125.09 GeV and explores multiple coupling parametrizations (κ-framework, cross-section/branching ratios, and stage-0 template cross sections). The results are broadly SM-consistent, with notable precision gains such as a ~50% improvement in ggH precision and substantial constraints on ttH, while also providing limits on possible BSM scenarios including 2HDM and MSSM frameworks. The work also emphasizes systematic treatment and cross-channel consistency, offering a robust set of tools for future Higgs precision tests and informing searches for extended Higgs sectors.

Abstract

Combined measurements of the production and decay rates of the Higgs boson, as well as its couplings to vector bosons and fermions, are presented. The analysis uses the LHC proton-proton collision data set recorded with the CMS detector in 2016 at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a W or Z boson, or a top quark-antiquark pair) and the following decay modes: H $\to$ $γγ$, ZZ, WW, $ττ$, bb, and $μμ$. Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be $μ$ $=$ 1.17 $\pm$ 0.10, assuming a Higgs boson mass of 125.09 GeV. Additional results are given for parametrizations with varying assumptions on the scaling behavior of the different production and decay modes, including generic ones based on ratios of cross sections and branching fractions or coupling modifiers. The results are compatible with the standard model predictions in all parametrizations considered. In addition, constraints are placed on various two Higgs doublet models.

Figures (8)

• Figure 1: Examples of leading-order Feynman diagrams for Higgs boson decays in the $H\xspace\to b\xspace b\xspace\xspace$, $H\xspace\to\tau\tau\xspace$, and $H\xspace\to{\mu}{\mu}\xspace$ (upper left); $H\xspace\to ZZ\xspace$ and $H\xspace\to\mathrm{W}\mathrm{W}\xspace$ (upper right); and $H\xspace\to\gamma\xspace\gamma\xspace\xspace$ (lower) channels.
• Figure 2: Examples of leading-order Feynman diagrams for the $g\xspace g\xspace H\xspace$ (upper left), $\mathrm{VBF}$ (upper right), $\mathrm{V}H\xspace$ (lower left), and $ttH\xspace$ (lower right) production modes.
• Figure 3: Examples of leading-order Feynman diagrams for the $g\xspace g\xspace\to ZH\xspace\xspace$ production mode.
• Figure 4: Examples of leading-order Feynman diagrams for $tH\xspace$ production via the $tH\xspace\mathrm{W}$ (upper left and right) and $tH\xspace\mathrm{q}$ (lower) modes.
• Figure 5: Summary plot of the fit to the per-production mode (left) and per-decay mode (right) signal strength modifiers. The thick and thin horizontal bars indicate the $\pm1\sigma$ and $\pm2\sigma$ uncertainties, respectively. Also shown are the $\pm1\sigma$ systematic components of the uncertainties. The last point in the per-production mode summary plot is taken from a separate fit and indicates the result of the combined overall signal strength $\mu$.