Anomalous gamma gamma interaction

TL;DR

This paper discusses unexpected experimental results in gamma gamma interactions at high transverse momentum, suggesting possible new physics such as quarks with larger or unit charges, and explores future collider options for testing these anomalies.

Contribution

It highlights discrepancies between LEP2 data and QCD predictions, proposing alternative models with different quark charge assumptions and suggesting future collider experiments for validation.

Findings

LEP2 data exceeds QCD predictions by about an order of magnitude

Data suggests quarks may have unit or larger charges

Future colliders could test these anomalous interactions

Abstract

Data from LEP2 on hadron production in gamma gamma interactions at high pT exceed the predictions of QCD by about an order of magnitude. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges of quarks. The data are suggestive of models where quarks have unit charges, or larger. Unequivocal tests could be made with the ILC or CLIC, but a plasma wakefield e-e- collider might provide the most affordable option.