Total Cross Section in gamma gamma Collisions at LEP

TL;DR

This paper measures the total cross section of gamma-gamma collisions at LEP energies, revealing a steeper energy dependence than in other hadronic interactions, and compares results with theoretical models.

Contribution

It provides new measurements of gamma-gamma total cross sections at high energies and compares them with theoretical predictions, highlighting differences in energy dependence.

Findings

Total cross section described by Regge parametrisation

Steeper rise with energy compared to hadron-hadron interactions

Data compared to various theoretical models

Abstract

The reaction e+e- -> e+e- gamma* gamma* -> e+e- hadrons for quasi-real photons is studied using data from root(s) = 183 GeV up to 202 GeV. Results on the total cross sections sigma(e+e- -> e+e- hadrons) and sigma(+e- gamma* gamma* -> e+e- hadrons) are given for the two-photon centre-of-mass energies 5 GeV < Wgammagamma < 185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the hadron-hadron and the photon-proton cross sections. The data are also compared to the expectations of different theoretical models.