Measurement of the Q**2 evolution of the photon structure function F2(gamma)

New measurements are presented of the photon structure function F_2^gamma(Q) at four values of Q^2 between 9 and 59 GeV/c^2 based on data collected with the OPAL detector at centre-of-mass energies of 161-172 GeV, with a total integrated luminosity of 18.1 pb^-1. The evolution of F_2^gamma with Q^2 in bins of x is determined in the Q^2 range from 1.86 to 135 GeV/c^2 using data taken at centre-of-mass energies of 91 GeV and 161-172 GeV. F_2^gamma is observed to increase with Q^2 with a slope of 1/alpha_em dF_2^gamma/dln(Q^2) = 0.10 +0.05 -0.03 measured in the range 0.1 < x < 0.6.

Note:

22 pages, LaTeX, 4 eps figures included, accepted by Phys. Lett. B Report-no: CERN-PPE/97-087

electron positron: colliding beams
equivalent photon approximation
photon electron: deep inelastic scattering
hadron: multiple production
energy flow: hadronic
photon: structure function
momentum transfer dependence
flavor: 4
OPAL
experimental results

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