Measurement of the hadronic photon structure function F2(gamma)(x,Q**2) in two-photon collisions

A measurement of the hadronic structure function F γ 2 (x, Q2 ) is performed with data taken by the ALEPH Collaboration in the years 1998 to 2000. At LEP centre-of-mass energies between 189 GeV and 207 GeV an integrated luminosity of 548.4 pb−1 is analyzed in two bins of the virtuality Q2 . Single-tag γ ∗γ events are selected in the low Q2 region with hQ2 i = 17.3 GeV2 and at high Q2 with hQ2 i = 67.2 GeV2 . The properties of the selected events are compared to Monte-Carlo calculations. A regularized Tikhonov unfolding technique is applied to correct for the detector acceptance and efficiency. Emphasis is put on a complete treatment of statistical and systematic uncertainties. The final results are compared to theoretical predictions and measurements from other experiments.