$\gamma \gamma$ cross-sections and $\gamma \gamma$ colliders

Abstract

We summarize the predictions of different models for total $\gamma \gamma$ cross-sections. The experimentaly observed rise of ${\sigma }_{\gamma \gamma }$ with $\sqrt{s_{\gamma \gamma }}$, faster than that for ${\sigma }_{\bar{p}p}$, ${\sigma }_{\gamma p}$ is in agreement with the predictions of the Eikonalized Minijet Models as opposed to those of the Regge-Pomeron models. We then show that a measurement of ${\sigma }_{\gamma \gamma }$ with an accuracy of $⪅8-9$ is necessary to distinguish among different Regge-Pomeron type models (among the different parametrisations of the EMM models) and a precision of $⪅$ 20% is required to distinguish among the predictions of the EMMs and of those models which treat like 'photon like a proton', for the energy range $300<\sqrt{s_{\gamma \gamma }}<500$ GeV. We further show that the difference in model predictions for ${\sigma }_{\gamma \gamma }$ of about a factor 2 at $\sqrt{s_{\gamma \gamma }}=700$ GeV reduces to $\sim$ 30% when folded with bremsstrahlung $\gamma$ spectra to calculate $\sigma (e^{+}{e}^{-}\to e^{+}{e}^{-}\gamma \gamma \to e^{+}{e}^{-}X)$. We point out then the special role that $\gamma \gamma$ colliders can play in shedding light on this

11 pages, 8 figures, LaTeX, uses elsart.cls. Talk to appear in the proceedings of the the International Workshop on High Energy Photon Colliders, DESY, Hamburg, June 2000

References in corpus (2)

• Hadronic cross-sections in gamma gamma processes and the next linear collider
• Models for Photon-photon Total Cross-sections

Cited by in corpus (2)

• TESLA Technical Design Report, Part VI, Chapter 1: The Photon Collider at TESLA
• Gold-plated processes at photon colliders