Testing CP Violation in ZZH Interactions at the LHC

TL;DR

This paper proposes methods to detect CP violation in ZZH interactions at the LHC by analyzing CP-odd observables and asymmetries, demonstrating potential for significant discovery with realistic data samples.

Contribution

It introduces a novel approach to measure CP violation in ZZH couplings using CP-odd observables and asymmetries at the LHC, including detailed analysis strategies.

Findings

CP asymmetry detectable at 3 sigma with 30 fb^-1

CP asymmetry detectable at 5 sigma with 50 fb^-1

Effective analysis suppresses SM backgrounds

Abstract

We study genuine CP-odd observables at the LHC to test the CP property of the ZZH interaction for a Higgs boson with mass below the threshold to a pair of gauge bosons via the process p,p -> Z,H -> l+,l-,b,bbar. We illustrate the analysis by including a CP-odd ZZH coupling, and show how to extract the CP asymmetries in the signal events. After selective kinematical cuts to suppress the SM backgrounds plus an optimal Log-likelihood analysis, we find that, with a CP violating coupling btilde = 0.25, a CP asymmetry may be established at a 3 sigma (5 sigma) level with an integrated luminosity of about 30 (50) fb^-1 at the LHC.