Extraction of parton distributions and

Abstract

We have performed a NLO QCD global fit of BCDMS, NMC, H1 and ZEUS data with full account of point-to-point correlations using the Bayesian approach to the treatment of systematic errors. Parton distributions in the proton with their experimental uncertainties, including both statistical and systematic, are obtained. The gluon distribution in a wide region of x is found to be softer than the gluon distribution extracted in standard global analyses which include prompt photon data. We obtain a robust estimate of $\alpha_{\mathrm{s}}(M_Z)=0.1146\pm0.0036 (\ge75\%$ C.L.) based on Chebyshev's inequality, which is compatible with an earlier determination of $\alpha_{\mathrm{s}}$ from the DIS data, but is less dependent on high-twist effects.