The gamma gamma to Z Z process and the search for virtual SUSY effects at a gamma gamma Collider

TL;DR

This paper analyzes the gamma gamma to ZZ process at high energy to identify potential virtual SUSY effects, proposing it as a tool for discovering new physics beyond the Standard Model.

Contribution

It provides the first detailed study of helicity amplitudes for gamma gamma to ZZ, including SUSY particle loop effects, and explores their signatures for new physics detection.

Findings

Amplitudes are mainly helicity-conserving and imaginary at 300 GeV.

Virtual SUSY particles like charginos and stops induce detectable signatures.

Combined analysis with other gamma gamma processes aids in identifying new physics.

Abstract

We study the helicity amplitudes of the process gamma gamma to ZZ in the Standard Model at high energy. These amplitudes receive contributions from the W and charged quark and lepton loops, analogous to those encountered in the gamma gamma to gamma gamma, gamma Z cases studied before. But gamma gamma to ZZ also receives contributions from the Higgs s-channel poles involving the effective Higgs-gamma gamma vertex. At energies of about 300 GeV, the amplitudes in all three processes are mainly helicity-conserving and almost purely imaginary; which renders them a very useful tool in searching for New Physics. As an example, a SUSY case is studied, and the signatures due to the virtual effects induced by a chargino-, charged slepton- or a lightest stop-loop in gamma gamma to ZZ, are explored. These signatures, combined with the analogous ones in gamma gamma to gamma gamma and gamma gamma to gamma Z, should help identifying the nature of possible New Physics particles.