Next-to-leading-order radiative parton model analysis of polarized deep inelastic lepton-nucleon scattering

A next-to-leading-order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton-nucleon scattering is presented within the framework of the radiative parton model. A consistent NLO formulation of the Q2 evolution of polarized parton distributions yields two sets of plausible NLO spin-dependent parton distributions in the conventional MS factorization scheme. They respect the fundamental positivity constraints down to the low resolution scale Q2=μ2NLO=0.34 GeV2. The Q2 dependence of the spin asymmetries Ap,n,d1(x,Q2) is similar to the leading-order (LO) one in the range 1≤Q2≤20 GeV2 and is shown to be non-negligible for x values relevant for the analysis of the present data and possibly forthcoming data at DESY HERA. copyright 1996 The American Physical Society