Higgs Up-Down CP Asymmetry at the LHC

TL;DR

This paper introduces a novel observable for detecting CP-violation in Higgs interactions with W bosons at the LHC, utilizing an asymmetry based on lepton distributions relative to a defined plane.

Contribution

It proposes a new CP-sensitive asymmetry measurement in Higgs production that leverages initial state fermion directions in proton-proton collisions.

Findings

Defines a CP-violating asymmetry observable.

Suggests rapidity cuts to enhance quark-antiquark discrimination.

Provides a method to probe Higgs CP properties at the LHC.

Abstract

We propose a new observable designed to probe CP-violating coupling of the Higgs boson to W bosons using associated Higgs production. We define an asymmetry that measures the number of leptons from W decays relative to the plane defined by the beam line and the Higgs boson momentum. The orientation of that plane is determined by the direction of fermions in the initial state, so that in a proton-proton collider it requires rapidity cuts that preferentially select quarks over antiquarks.