Measurement of the Higgs boson coupling properties in the H → ZZ∗ → 4ℓ decay channel at $$ \sqrt{s}=13 $$ TeV with the ATLAS detector

Abstract

Abstract:The coupling properties of the Higgs boson are studied in the four-lepton (e, µ) decay channel using 36.1 fb −1 of pp collision data from the LHC at a centre-of-mass energy of 13 TeV collected by the ATLAS detector. Cross sections are measured for the main production modes in several exclusive regions of the Higgs boson production phase space and are interpreted in terms of coupling modifiers. The inclusive cross section times branching ratio for H → ZZ * decay and for a Higgs boson absolute rapidity below 2.5 is measured to be 1.73+0.10 −0.08 (exp.)±0.04(th.) pb compared to the Standard Model prediction of 1.34±0.09 pb. In addition, the tensor structure of the Higgs boson couplings is studied using an effective Lagrangian approach for the description of interactions beyond the Standard Model. Constraints are placed on the non-Standard-Model CP-even and CP-odd couplings to Z bosons and on the CP-odd coupling to gluons.

Higgs couplings at high scales

“…The ATLAS and CMS collaborations have so far established a consistent picture of the Higgs boson couplings at the EW scale Q 2 ≈ m 2 h to top quarks directly [13,14] and indirectly [15,16], and to W þ W − [17,18], ZZ [15,16], ττ [19,20], and bb directly [21,22]. Experiments at the LHC will continue to probe the Higgs sector both at the Higgs mass scale as well as at higher scales.…”

Constraining new physics from Higgs measurements with Lilith: update to LHC Run 2 results

“…In order to reasonably reproduce the C F vs. C V fit of ATLAS ( Fig. 8b of [21]), we fit the 1D profile likelihoods for µ(ggH, ZZ * ) and µ(VBF, ZZ * ) shown in Aux. Figs.…”

“…Figs. 7a and 7b of [21] as Poisson distributions. This gives µ(ggH, ZZ * ) 1.12 +0.25 −0.22 and µ(VBF, ZZ * ) 3.88 +1.75 −1.46 , which we implement as a bivariate Poisson distribution with correlation ρ = −0.41 (from Aux.…”

“…Figs. 7a and 7b of [21]; the ggH vs. VBF likelihood is then approximated as a bivariate Poissonian with correlation −0.41 (see text for more details). The 68%, 95% and 99.7% CL regions obtained with Lilith are shown as red, orange and yellow areas, and compared to the 68% and 95% CL contours from ATLAS (in blue).…”

Flavorful two-Higgs-doublet models with a twist

“…As in [30], the BSM predictions are obtained by rescaling the SM results with appropriate combinations of coupling modifiers. For current LHC results we use the run 1 combination from [35], in addition we take the run 2 results for h 1 → ZZ * [36,37], h 1 → W W * [38], h 1 → γγ [39,40],…”