Total hadronic cross-section
photon-photon interactions at LEP
The OPAL Collaboration
G.Abbiendi - et al.
Dipartimento di Fisica dell' Università di Bologna and INFN,
40126 Bologna, Italy
Received: 3 June 1999 / Published online: 6 April 2000 - © Springer-Verlag 2000
The total hadronic cross-section for the interaction of real photons, , is measured for centre-of-mass energies GeV. The cross-section is extracted from a measurement of the process , using a luminosity function for the photon flux together with form factors for extrapolating to real photons (Q2=0 GeV2). The data were taken with the OPAL detector at LEP at centre-of-mass energies and 183 GeV. The cross-section is compared with Regge factorisation and with the energy dependence observed in p and pp interactions. The data are also compared to models which predict a faster rise of compared to p and pp interactions due to additional hard interactions not present in hadronic collisions.
Copyright Società Italiana di Fisica, Springer-Verlag 2000