Tree-level Interference in VBF production of Vh

TL;DR

This paper investigates a process where two electroweak vector bosons scatter into a vector boson and a Higgs, revealing interference effects that are sensitive to deviations in Higgs couplings, especially at high-energy lepton colliders.

Contribution

It demonstrates that high-energy lepton colliders can effectively probe the sign of the Higgs coupling ratio to W and Z bosons through VBF processes.

Findings

High-energy lepton colliders can exclude $\, ilde{ ext{lambda}}_{WZ} \,\simeq -1$ with modest data.

Tree-level interference in $VV ightarrow Vh$ is sensitive to Higgs coupling deviations.

The process grows with energy if Higgs couplings deviate from Standard Model values.

Abstract

Vector boson scattering is a well known probe of electroweak symmetry breaking. Here we study a related process of two electroweak vector bosons scattering into a vector boson and a Higgs boson ($VV \rightarrow Vh, V=W,Z$). This process exhibits tree level interference and grows with energy if the Higgs couplings to electroweak bosons deviate from their Standard Model values. Therefore, this process is particularly sensitive to the relative sign of the ratio of the coupling between the Higgs and the $W$ and $Z$, $\lambda_{WZ}$. In this work we show that a high energy lepton collider is well suited to study this process through vector boson fusion, estimate the potential sensitivity to this ratio, and show that a relatively modest amount of data can exclude $\lambda_{WZ} \simeq -1$.