Extended Scalar Sectors, Effective Operators and Observed Data

Abstract

The available data on the 125 GeV scalar h is analysed to explore new physics in the electroweak symmetry breaking sector. The first part of the study is model-independent, with h couplings to standard model particles scaled by some free parameters. At the same time, the additional loop contributions to h→γγ and h→Zγ , mediated by charged scalar contributions in the extended scalar sector, are treated in terms of gauge-invariant effective operators. We fit the existing data to obtain marginalized 1 σ and 2 σ regions in the space of the coefficients of such effective operators, by considering the correlation between, say, the gluon fusion and vector-boson fusion channels, as reflected in a non-diagonal covariance matrix. After thus obtaining model-independent fits, the allowed values of the coefficients are translated into permissible regions of the parameter spaces of several specific models.