Scattering of W and Z Bosons at High-Energy Lepton Colliders

TL;DR

This paper investigates high-energy W and Z boson scattering at future electron-positron colliders, using effective theories and simplified models to explore potential deviations from the Standard Model and assess collider sensitivities.

Contribution

It introduces a unitarization approach for modeling W/Z scattering in effective theories and simplified models, providing benchmark scenarios for collider studies.

Findings

Benchmark scenarios for W/Z scattering at 1-3 TeV colliders.

Optimized cuts for vector boson scattering modes.

Sensitivity estimates for new physics parameters.

Abstract

We present a new study of quasi-elastic $W$ and $Z$ scattering processes in high-energy $e^+e^-$ collisions, based on and extrapolating the low-energy effective theory which extends the Standard Model with a 125 GeV Higgs boson. Besides parameterizing deviations in terms of the dimension-8 operators that arise in the effective theory, we also study simplified models of new physics in $W/Z$ scattering in terms of scalar and tensor resonance multiplets. The high-energy asymptotics of all models is regulated by a universal unitarization procedure. This enables us to provide benchmark scenarios which can be meaningfully evaluated off-shell and in exclusive event samples, and to determine the sensitivity of an $e^+e^-$ collider to the model parameters. We analyze the longitudinal vector boson scattering modes, where we optimize the cuts for the fiducial cross section for different collider scenarios. Here, we choose energy stages of 1.0, 1.4 and 3 TeV, as motivated by the extendability of the ILC project and the staging scenario of the CLIC project.