Probing Higgs couplings at LHC and beyond

TL;DR

This paper explores methods to precisely measure Higgs boson couplings at the 14 TeV LHC using angular distributions, aiming to detect deviations from the Standard Model and probe potential new physics beyond it.

Contribution

It introduces a framework for extracting Higgs couplings and testing their momentum dependence through angular asymmetries in future LHC data, including scenarios with CP violation.

Findings

Angular asymmetries can measure coupling ratios and phases.

The analysis benchmarks SM Higgs and beyond scenarios.

Method to test momentum independence of Higgs couplings.

Abstract

The study of the Higgs couplings following its discovery is the priority of future LHC runs. A hint of anomalous nature will be exhibited via its coupling to the Standard Model(SM) particles and open up new domain of phenomenological study of physics beyond the Standard Model. The enhanced statistics from next LHC runs will enable entry into the precision era to study the properties of Higgs with greater details. In this paper we present how one can extract Higgs couplings in future LHC runs at 14 TeV via $H \rightarrow Z Z^* \rightarrow 4 \ell$, using observables constructed from angular distributions for the Standard Model Higgs and Higgs with mixed CP configuration. We show how angular asymmetries can be used to measure the ratios of the couplings and the relative phases at LHC. We benchmark our analysis finding out the angular asymmetries and the best fit values of the ratios of the couplings for SM Higgs, CP-odd admixture, CP-even higher derivative contribution and when CP-even higher derivative contribution and CP-odd admixture are both present. In the Standard Model, $HZZ$ couplings have no momentum dependence. It is thus essential to demonstrate the momentum independence of the couplings to establish the couplings are SM like in nature. In this work we show how one can test the momentum independence of the Standard Model like coupling using angular asymmetries. We develop the necessary tools and demonstrate how to study the momentum dependence can be studied at future LHC runs.