ATLAS-CONF-2015-044; CMS-PAS-HIG-15-002

ATLAS-CONF-2015-044; CMS-PAS-HIG-15-002
Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC $pp$ collision data at $\sqrt{s} =$ 7 and 8 TeV
ATLAS and CMS Collaborations
September 2015

Abstract: Combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes and of the $H \to ZZ$, $WW$, $\gamma\gamma$, $\tau\tau$, $bb$ and $\mu\mu$ decay modes. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined Higgs boson mass measurement by ATLAS and CMS. The analysis uses the LHC proton-proton collision datasets recorded by the ATLAS and CMS detectors in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb$^{-1}$ at $\sqrt{s}=$ 7 TeV and 20 fb$^{-1}$ at $\sqrt{s} =$ 8 TeV. The Higgs boson production and decay rates of the two experiments are combined within the context of two generic parameterisations: one based on ratios of cross sections and branching ratios and the other based on ratios of coupling modifiers, introduced within the context of a leading-order Higgs boson coupling framework. The combined signal yield relative to the Standard Model expectation is measured to be 1.09 $\pm$ 0.11 and the combination of the two experiments leads to observed significances of the $V$BF production process and of the $H \to \tau \tau $ decay at the level of 5.4$\sigma$ and 5.5$\sigma$, respectively. Several interpretations of the results with more model-dependent parameterisations, derived from the generic ones, are also given. The data are consistent with the Standard Model predictions for all parameterisations considered.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 08 (2016) 045. The superseded preliminary plots can be found here.

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