Abstract submitted to the
         International Europhysics Conference on High Energy Physics
                  July 12 - 18, 2001, Budapest, Hungary
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               ZEUS NLO-QCD fit to determine proton PDFs and alpha_s

                    
                               ZEUS Collaboration



                                    Abstract


      A next-to-leading-order QCD fit has been performed on e^+p deep 
      inelastic scattering data taken with the ZEUS detector at HERA using 
      an integrated luminosity of 30 pb^{-1}. The gluon and quark densities 
      of the proton have been extracted.  Experimental systematic errors 
      were considered in this analysis taking into account their 
      point-to-point correlations. This allows a correct evaluation 
      of the uncertainties in the extracted parton densities. In addition, 
      the strong coupling constant, alpha_s, was determined simultaneously.