Tests of Low Scale Quantum Gravity in $e^-e^-$ and $\gamma \gamma$ Collisions

TL;DR

This paper investigates how theories of large extra dimensions could modify scattering processes in electron-electron and gamma-gamma collisions, potentially revealing signs of low-scale quantum gravity at TeV energies.

Contribution

It analyzes the effects of Kaluza-Klein graviton exchanges on specific scattering processes and highlights the importance of polarization in enhancing detection sensitivity.

Findings

Kaluza-Klein graviton exchanges introduce new dimension-8 operators affecting scattering.

Polarization of initial and final states improves sensitivity to graviton effects.

Results suggest possible observable deviations from Standard Model predictions at TeV energies.

Abstract

Arkani-Hamed, Dimopoulos and Dvali have recently proposed that gravity may become strong at energies near 1 TeV due to the existence of large extra dimensions thus `removing' the hierarchy problem. In this talk we examine the exchange of towers of Kaluza-Klein gravitons and their influence on Moller scattering as well as the production of pairs of massive gauge bosons in $\gamma \gamma$ collisions. These tower exchanges lead to a set of new dimension-8 operators that can significant alter the Standard Model expectations for these processes. In the case of $\gamma \gamma$ collisions, the role of polarization for both the initial state photons and the final state gauge bosons in improving sensitivity to graviton exchange is emphasized.