EPJ

2021 Impact factor 4.991
EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 14, 199-212
DOI 10.1007/s100520000352

Total hadronic cross-section
of photon-photon interactions at LEP

The OPAL Collaboration

G.Abbiendi$^{\rm 2}$ - et al.

$^{\rm 2}$ Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy

Received: 3 June 1999 / Published online: 6 April 2000 - © Springer-Verlag 2000

Abstract
The total hadronic cross-section $\sigma_{\gamma\gamma}(W)$ for the interaction of real photons, $\gamma\gamma\rightarrow\mbox{~hadrons}$, is measured for $\gamma\gamma$ centre-of-mass energies $10\le W \le 110$ GeV. The cross-section is extracted from a measurement of the process $\mbox{${\rm e}^+{\rm e}^-$ }\rightarrow\mbox{${\rm e}^+{\rm e}^-$ }\gamma^*\gamma^*\rightarrow \mbox{${\rm e}^+{\rm e}^-$ }+\mbox{~hadrons}$, 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 $\mbox{${\rm e}^+{\rm e}^-$ }$centre-of-mass energies $\mbox{$\sqrt{s}_{\rm ee}$ }=161, 172$ and 183 GeV. The cross-section $\sigma_{\gamma\gamma}(W)$ is compared with Regge factorisation and with the energy dependence observed in $\gamma$p and pp interactions. The data are also compared to models which predict a faster rise of $\sigma_{\gamma\gamma}(W)$ compared to $\gamma$p and pp interactions due to additional hard $\gamma\gamma$ interactions not present in hadronic collisions.

Copyright Società Italiana di Fisica, Springer-Verlag 2000

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