Real photon structure at an e^+e^- linear collider

TL;DR

This paper updates the potential for measuring the photon structure function at a future high-energy e^+e^- collider, discusses theoretical evolution, and examines the sensitivity to the strong coupling constant.

Contribution

It provides updated kinematic coverage estimates, revisits the perturbative evolution of F_2^gamma, and analyzes the sensitivity to alpha_s, addressing recent critiques of NLO analyses.

Findings

Updated luminosity and detector parameter estimates improve measurement prospects.

The evolution of F_2^gamma can be reliably modeled within perturbative QCD.

Hadronic and photonic structure functions show different sensitivities to alpha_s.

Abstract

Previous studies of the kinematic coverage for measuring the photon structure function F_2^gamma at a future 500 GeV e^+e^- linear collider are updated using current estimates of luminosities and important detector parameters. The perturbative expansion for the evolution of F_2^gamma is briefly recalled in view of a recent claim that all existing next-to-leading order analyses of the photon structure are incorrect. A simple illustration is given of the different sensitivities of hadronic and photonic structure functions on the strong coupling constant alpha_s.