The Measurement of Azimuthal Asymmetries in Deep Inelastic Scattering
  The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time. 
N H Brook (University of Bristol, on behalf of the ZEUS Collab.)