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Download or read book RESULTS AND INTERPRETATIONS OF THE SPIN STRUCTURE EXPERIMENTS AT SLAC. written by and published by . This book was released on 2003 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the recent experiments E154 and E155 at SLAC the spin-dependent structure functions g1(superscript n), g1{sup p}, and g1{sup d} of the neutron, proton, and deuteron were measured by scattering longitudinally polarized 48:3 GeV electrons off longitudinally polarized targets. We report on the measurement of g1(superscript n) by E154, and on the preliminary results on g1° from E155. The SLAC results provide the most precise determination to date of the polarized structure functions. We observe relatively large values of g1(superscript n) at low x that call into question the reliability of data extrapolation to x -> 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. We perform a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin-dependent structure functions. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, we evolve the data to Q2 = 5 GeV2, determine the first moments of the polarized structure functions of the proton and neutron, and find agreement with the Bjorken sum rule.