Abstract
Abstract We consider the Higgs boson decay processes and its production, and provide a parameterisation tailored for testing models of new physics beyond the Standard Model. We also compare our formalism to other existing parameterisations based on scaling factors in front of the couplings and to effective Lagrangian approaches. Different formalisms allow to best address different aspects of the Higgs boson physics. The choice of a particular parameterisation depends on a non-obvious balance of quantity and quality of the available experimental data, envisaged purpose for the parameterisation and degree of model independence, importance of the radiative corrections, scale at which new particles appear explicitly in the physical spectrum. At present only simple parameterisations with a limited number of fit parameters can be performed, but this situation will improve with the forthcoming experimental LHC data. Detailed fits can only be performed by the experimental collaborations at present, as the full information on the different decay modes is not completely available in the public domain. It is therefore important that different approaches are considered and that the most detailed information is made available to allow testing the different aspects of the Higgs boson physics and the possible hints beyond the Standard Model.
Highlights
We consider the Higgs boson decay processes and its production, and provide a parameterisation tailored for testing models of new physics beyond the Standard Model
It is important that different approaches are considered and that the most detailed information is made available to allow testing the different aspects of the Higgs boson physics and the possible hints beyond the Standard Model
We propose an extension of the parameterisation in ref. [2], where the contribution of loops of New Physics to the H → gg and H → γγ modes is explicitly disentangled from the modification of tree level couplings, removing correlations among the various parameters
Summary
The data analysed by the two collaborations (ATLAS and CMS) is presented in terms of measured cross sections in the relevant decay channels and for various selection rules: in the following, we will make use of as much information as it is available. H → γγ: in CMS, information was given in [14]: in table 2 of the reference, one can find the product σpi = (σpSMǫip)/( p′ σpS′Mǫip′) for each selection and production channel, whereas the best fit values as well as the uncertainties can be found in another table on the corresponding TWiki [15], for a Higgs mass of mH = 125 GeV Those results are shown in table 1. The results from the ATLAS collaboration, on the other hand, can be found in note [16], where the selection channel efficiencies are given, and the best fit values had to be extracted from figures 14a and 14b for 7 TeV and 8 TeV respectively The values of χ2 computed this way are compared to the exclusion thresholds at 68 and 95% CL for a m degrees of freedom χ2 distribution, where m is the number of channels i minus the number of independent fitted parameters (i.e. the number of independent parameters which value are fitted to the data)
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