The gamma gamma to gamma gamma process in the Standard and SUSY models at high energies

TL;DR

This paper analyzes the high-energy gamma gamma to gamma gamma scattering process within the Standard Model and supersymmetric models, focusing on helicity amplitudes and their observable characteristics.

Contribution

It provides new simple expressions for 1-loop functions and explores the behavior of helicity amplitudes across parameter space in both models.

Findings

SUSY contributions dominate above the superpartner production threshold.

Interference effects are most significant where SM amplitudes are primarily imaginary.

Detailed characteristics of various observables are thoroughly studied.

Abstract

We study the helicity amplitudes of the process \gamma \gamma \to \gamma \gamma at high energy, which in the standard and SUSY models first arise at the one-loop order. In the standard model (SM), the diagrams involve W and charged quark and lepton loops, while in SUSY we also have contributions from chargino, charged sfermion and Higgs loop diagrams. The SUSY contributions are most important in the region above the threshold for producing the supersymmetric partners; since there, they interfere most effectively with the primarily imaginary SM amplitudes. Simple expressions for the relevant 1-loop functions are given, which provide a direct overview of the behaviour of the helicity amplitudes in the whole parameter space at high energies. The various characteristics of a large set of observables are studied in detail.