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

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.

v2: 32 pages, 6 figures, 2 tables, minor changes: references added, some numbers updated, conclusions unchanged; version accepted for publication in JHEP