Nucleon structure functions from deep inelastic muon scattering

The New Muon Collaboration has measured deep inelastic muon scattering simultaneously on hydrogen and deuterium at incident muon energies of 90 and 280 Ge V. The data cover a wide kinematic range 0.008 < x < 0. 7 and 0.8 < Q2 < 50 GeV2 • Preliminary results are presented on the nucleon structure functions Ff and Ff, In the region of kinematic overlap the data are in good agreement with previous results from SLAC and BCDMS (x > 0.07) but disagree with those obtained from a recent analysis of EMC (x > 0.03). Presented is a next-to-leading order QCD analysis of the NMC data. We find good agreement between theory and data. The flavour non-singlet and singlet quark distributions as well as the gluon distribution are extracted with good precision down to low values of x (0.008). These results are compared to low-x extrapolations based on recent parton distribution fits. Also given is a preliminary result on the strong coupling constant as.