A Study of Two-Prong Two-Photon Events at the Z0 Resonance

Abstract

A study of electron-positron scattering leading to two electron-positron pairs via a two-photon interaction has been carried out at the Stanford Linear Accelerator Center (SLAC). The case where one pair is observed in the detector was investigated. These events were produced at the SLAC Linear Collider (SLC) operating in the center-of-mass energy range from 89.2 to 9.30 GeV. The data was collected using the Mark II detector. Two-photon interactions are described by the theory of quantum electrodynamics (QED). Such processes can be a significant background to new particle searches; consequently, and understanding of their production is imperative. A deviation from the event rate predicted by QED might indicate the existence of new particles. The event rate may also be useful as a luminosity monitor during data collection. The data sample from the Mark II is searched for events which have features indicative of two-photon events. For comparison with theory, the Berends, Daverveldt, and Keiss Monte Carlo event generator is used to simulate events according to QED theory. The data is compared to the theoretical predictions. Given the low event statistics from the SLC data run, the results are consistent with the QED theoretical prediction. However, due to the low statistics, this measurement cannot be used to indicate non-deviation from QED predictions.