Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm, A cut on x(gamma)(OBS), the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and in the photon, The oss dependence of the dijet cross sections on pseudorapidity has been measured for x(gamma)(OBS)greater than or equal to 0.75 and x(gamma)(OBS)<0.75. The former is sensitive to the gluon momentum density in the proton. The latter is sensitive to the gluon in the photon. The cross sections are corrected for detector acceptance and compared to leading order QCD calculations.
Derrick, M., Krakauer, D., Magill, S., Mikunas, D., Musgrave, B., Repond, J., et al. (1995). DIJET CROSS-SECTIONS IN PHOTOPRODUCTION AT HERA RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008. PHYSICS LETTERS. SECTION B, 348(3-4), 665-680 [10.1016/0370-2693(95)00275-P].