Tests of Low Scale Gravity via Gauge Boson Pair Production in $\gamma \gamma$ Collisions

TL;DR

This paper investigates how theories of low-scale gravity with extra dimensions could be tested through gauge boson pair production in gamma-gamma collisions, highlighting the potential for significant deviations from Standard Model predictions.

Contribution

It introduces the impact of Kaluza-Klein graviton tower exchanges on gauge boson pair production and emphasizes the role of polarization in enhancing detection sensitivity.

Findings

Graviton tower exchange can significantly alter gauge boson production rates.

Polarization improves sensitivity to graviton effects.

Gamma-gamma to W+W- channel offers the highest discovery potential.

Abstract

Arkani-Hamed, Dimopoulos and Dvali have recently proposed that gravity may become strong at energies near 1 TeV thus removing the hierarchy problem. This scenario can be tested in several ways at present and future colliders. In this paper we examine the exchange of towers of Kaluza-Klein gravitons and their influence on the production of pairs of massive gauge bosons in $\gamma \gamma$ collisions. These tower exchanges are shown to lead to a new dimension-8 operator that can significant alter the Standard Model expectations for these processes. The role of polarization for both the initial state photons and the final state gauge bosons in improving sensitivity to graviton exchange is emphasized. We find that the discovery reach for graviton tower exchange in the $\gamma \gamma \to W^+W^-$ channel to be significantly greater than for any other process so far examined.