Interpretation of precision tests in the Higgs sector in terms of physics beyond the Standard Model

TL;DR

This paper explores how deviations in Higgs couplings from Standard Model predictions can be interpreted through effective operators, providing a model-independent framework for understanding potential new physics in the Higgs sector.

Contribution

It introduces a model-independent approach using effective $d=6$ operators to interpret Higgs coupling deviations, linking them to possible new physics mediators and correlations.

Findings

Current measurements suggest the need for multiple new mediators.

Specific relationships among couplings can be identified with improved measurements.

Future data from Higgs decay channels will refine the interpretation of new physics.

Abstract

We demonstrate how the measurements of the Higgs-fermion and Higgs-gauge boson couplings can be interpreted in terms of physics beyond the Standard Model in a model-independent way. That is, we describe deviations from the Standard Model by effective $d=6$ operators made of Higgs fields and gauge fields, under the hypothesis that the new physics may show up in the Higgs sector only and the effective operators are generated at tree level. While the effective operator coefficients are independent in general, the completion of the theory at high energies will lead to specific correlations which will be recovered between Higgs-fermion and Higgs-gauge boson couplings. We demonstrate that the current measurement of these couplings in terms of tree-level new physics requires several new mediators with specific relationships among different couplings. New insights in the effective theory and mediator spaces can be expected for improved measurements from the inclusive $H \rightarrow \tau \tau$ and the exclusive vector boson fusion-dominated $H \rightarrow \gamma \gamma$ search channels, as well as the measurement of the Higgs self-couplings, including higher order couplings which do not exist in the Standard Model.