Comparison of Dijet Cross Sections vs Q^2 with Various Monte Carlo Models

Abstract

The dijet cross section as a function of both the fraction of the photon momentum participating in the hard process, x_\gamma^{OBS}, and the photon's virtuality, Q^2, is compared with the predictions of Herwig 5.9 for various photon parton distribution functions. The ratio of dijet cross sections with x_\gamma^{OBS} < 0.75 and x_\gamma^{OBS} > 0.75 is measured as a function of Q^2. This ratio is found to decrease as Q^2 increases consistent with the hypothesis that the photon parton distribution functions decrease with increasing photon virtuality.