Dijet and multijet photoproduction at HERA/ZEUS

Recent results on high-ET dijet and three jet cross sections in photoproduction at HERA are reported. The measured cross sections are compared with the Next-to-Leading Order (NLO) QCD calculations. In general, the dijet cross sections show good agreement with the NLO calculations for the measured ET range (>14 GeV). However, an excess over the NLO is observed even for the kinematic region where the theoretical uncertainties are small. The three jet cross sections show good agreement with NLO QCD and the Monte Carlo models. The data exclude parton shower (PS) models without colour coherence effects