Adding Pseudo-Observables to the Four-Lepton Experimentalist's Toolbox

TL;DR

This paper introduces the use of pseudo-observables in analyzing the Higgs boson decaying to four leptons, enhancing the toolkit for probing Higgs properties and potential new physics effects.

Contribution

It relates pseudo-observables to amplitude and Lagrangian approaches, and provides sensitivity projections and analysis methods for $H\to 4\ell$ studies.

Findings

Pseudo-observables offer a versatile parametrization method.

Kinematic distributions and rate ratios improve sensitivity.

Projections indicate enhanced detection capabilities in novel scenarios.

Abstract

The "golden" channel, in which the newly-discovered Higgs boson decays to four leptons by means of intermediate vector bosons, is important for determining the properties of the Higgs boson and for searching for subtle new physics effects. Different approaches exist for parametrizing the relevant Higgs couplings in this channel; here we relate the use of pseudo-observables to methods based on specifying the most general amplitude or Lagrangian terms for the $HVV$ interactions. We also provide projections for sensitivity in this channel in several novel scenarios, illustrating the use of pseudo-observables, and analyze the role of kinematic distributions and (ratios of) rates in such $H\to4\ell$ studies.