A fully differential SMEFT analysis of the golden channel using the method of moments

TL;DR

This paper employs the Method of Moments for a detailed differential analysis of Higgs decay to four leptons, effectively constraining gauge-Higgs couplings and reducing parameter degeneracies, leading to the strongest bounds on anomalous couplings.

Contribution

It introduces a fully differential SMEFT analysis of the Higgs to four leptons channel using the Method of Moments, improving constraints on gauge-Higgs couplings.

Findings

Provides very good constraints on effective operators.

Minimizes degeneracies in parameter space.

Achieves the strongest bounds on anomalous gauge-Higgs couplings.

Abstract

The Method of Moments is a powerful framework to disentangle the relative contributions of amplitudes of a specific process to its various phase space regions. We apply this method to carry out a fully differential analysis of the Higgs decay channel $h \to 4\ell$ and constrain gauge-Higgs coupling modifications parametrised by dimension-six effective operators. We find that this analysis approach provides very good constraints and minimises degeneracies in the parameter space of the effective theory. By combining the decay $h \to 4\ell$ with Higgs-associated production processes, $Wh$ and $Zh$, we obtain the strongest reported bounds on anomalous gauge-Higgs couplings.