Diphoton Signals for Large Extra Dimensions at the Tevatron and CERN LHC

TL;DR

This paper investigates how hadron colliders like the Tevatron and LHC can detect large extra dimensions through photon pair production, with graviton exchange significantly enhancing the signals if the quantum gravity scale is in the TeV range.

Contribution

It provides a detailed analysis of diphoton production processes including graviton effects, estimating the collider reach for probing extra dimensions up to several TeV.

Findings

Tevatron can probe quantum gravity scale up to 1.5--1.9 TeV

LHC can extend the search to 5.3--6.7 TeV

Graviton exchange can significantly enhance diphoton production

Abstract

We analyze the potentiality of hadron colliders to search for large extra dimensions via the production of photon pairs. The virtual exchange of Kaluza--Klein gravitons can significantly enhance this processes provided the quantum gravity scale ($M_S$) is in the TeV range. We studied in detail the subprocesses $q \bar{q} \to \gamma \gamma$ and $g g \to \gamma \gamma$ taking into account the complete Standard Model and graviton contributions as well as the unitarity constraints. We show that the Tevatron Run II will be able to probe $M_S$ up to 1.5--1.9 TeV at 2$\sigma$ level, while the LHC can extend this search to 5.3--6.7 TeV, depending on the number of extra dimensions.