Abstract
The strength and tensor structure of the Higgs boson's interactions are investigated using an effective Lagrangian, which introduces additional CP-even and CP-odd interactions that lead to changes in the kinematic properties of the Higgs boson and associated jet spectra with respect to the Standard Model. The parameters of the effective Lagrangian are probed using a fit to five differential cross sections previously measured by the ATLAS experiment in the H→γγ decay channel with an integrated luminosity of 20.3 fb−1 at s=8 TeV. In order to perform a simultaneous fit to the five distributions, the statistical correlations between them are determined by re-analysing the H→γγ candidate events in the proton–proton collision data. No significant deviations from the Standard Model predictions are observed and limits on the effective Lagrangian parameters are derived. The statistical correlations are made publicly available to allow for future analysis of theories with non-Standard Model interactions.
Highlights
The discovery of a Higgs boson at the ATLAS and CMS experiments [1,2] offers a new opportunity to search for physics beyond the Standard Model (SM) by examining the strength and structure of the Higgs boson’s interactions with other particles
The φ jj distribution is sensitive to the cg parameter through the gluon fusion production mechanism (Figs. 2 and 3) and the limit on cg is improved with the inclusion of this data in the fit
The 68% and 95% confidence regions obtained from scanning cHW and cHW are shown in Fig. 6, after setting cHB = cHW and cHB = cHW to ensure that the partial width for H → Z γ is unchanged from the SM prediction
Summary
The discovery of a Higgs boson at the ATLAS and CMS experiments [1,2] offers a new opportunity to search for physics beyond the Standard Model (SM) by examining the strength and structure of the Higgs boson’s interactions with other particles. An alternative framework for probing physics beyond the SM is the effective field theory (EFT) approach [3,4,5,6,7,8], whereby the SM Lagrangian is augmented by additional operators of dimension six or higher Some of these operators produce new tensor structures for the interactions between the Higgs boson and the SM particles, which can modify the shapes of the Higgs boson kinematic distributions as well as the associated jet spectra. To perform a simultaneous analysis of these distributions, the statistical correlations between bins of different distributions need to be included in the fit procedure These correlations are evaluated by analysing the H → γ γ candidate events in the data, and are published as part of this Letter to allow future studies of new physics that produces non-SM kinematic distributions for H → γ γ
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