The hadronic structure function of the photon F2γ (x, Q2) is measured as a function of Bjorken x and of the photon virtuality Q2 using deep-inelastic scattering data taken by the OPAL detector at LEP at e+e- centre-of-mass energies from 183 to 209 GeV. Previous OPAL measurements of the x dependence of F2γ are extended to an average Q2 of (Q2) = 780 GeV2 using data in the kinematic range 0.15 < × < 0.98. The Q2 evolution of F2γ is studied for 12.1 < (Q2) < 780 GeV2 using three ranges of x. As predicted by QCD, the data show positive scaling violations in F2γ with F2γ (Q2)/α = (0.08 ± 0.02-0.03+0.05)+(0.13 ± 0.01 -0.01+0.01) 1n Q2, where Q2 is in GeV2, for the central x region 0.10-0.60. Several parameterisations of F2γ are in qualitative agreement with the measurements whereas the quark-parton model prediction fails to describe the data.
|Number of pages||16|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - May 9 2002|