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The deep-inelastic electromagnetic structure functions of deuterium and aluminum nuclei have been measured. The kinematic dependence of the ratio of aluminum and deuterium structure functions is similar to the dependence of the ratio of steel and deuterium structure functions, and provides further evidence for the distortion of the quark momentum distributions of nucleons bound in a nucleus.
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We report the extraction of R = σ L / σ T from a global analysis of eight SLAC deep inelastic experiments on e-p and e-d scattering performed between 1970 and 1985. Values of R p , R d , and R d − R p are determined over the entire SLAC kinematic range: 0.1⩽ x ⩽0.9 and 0.6⩽ Q 2 ⩽20.0 (GeV/ c ) 2 . We find that R p = R d . Measured values of R ( x , Q 2 ) are larger than predictions based on perturbative QCD and on QCD with the inclusion of kinematic target mass terms, indicating that dynamical higher twist effects may be important in the SLAC kinematic range.
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Data from experiment E-140.
Global extracting of R from all the experiments.
We present a next-to-leading order QCD analysis of the presently available data on the spin structure function g1 including the final data from the Spin Muon Collaboration. We present results for the first moments of the proton, deuteron, and neutron structure functions, and determine singlet and nonsinglet parton distributions in two factorization schemes. We also test the Bjorken sum rule and find agreement with the theoretical prediction at the level of 10%.
The second systematic (DSYS) error is due to QCD evolution.
First moments of the fitted function G1 evaluated on unmeasured X regions. Total uncertainties due to experimental systematics and theoretical sourc es in the QCD evolution.
First moment of fitted G1 evaluated on the whole X region.
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This paper presents the results of the analysis of a single-arm inelastic-electron-scattering experiment at an angle of 4°. We present data on the turnon of scaling in the low-q2 region 0.1<q2<1.8, the neutron-proton comparison at large values of the scaling variable ω, resonance excitation, and the shadowing in scattering from heavy nuclei.
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The deep-inelastic electromagnetic structure functions of steel, deuterium, and hydrogen nuclei have been measured with use of the high-energy electron beam at the Stanford Linear Accelerator Center. The ratio of the structure functions of steel and deuterium cannot be understood simply by corrections due to Fermi-motion effects. The data indicate that the quark momentum distributions in the nucleon become distorted in the nucleus. The present results are consistent with recent measurements with high-energy muon beams.
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We have carried out an experimental study of the neutron and proton deep-inelastic electromagnetic structure functions. The structure functions were extracted from electron-proton and electron-deuteron differential cross sections measured in three experiments spanning the angles 6°, 10°, 15°, 18°, 19°, 26°, and 34°. We report primarily on the large-angle (15°-34°) measurements. Neutron cross sections were extracted from the deuteron data using an impulse approximation. Our results are consistent with the hypothesis that the nucleon is composed of pointlike constituents. The variation of the cross section with angle suggests that the hypothetical constituents have spin ½. The data for σnσp, the ratio of the neutron and proton differential cross sections, are in the range 0.25 to 1.0, and are within the limits imposed by the quark model. Detailed studies of the structure functions were made for a range of the scaling variable ω from ω=1.3 to ω=10.0, and for a range of invariant four-momentum transfer Q2 from 1.0 to 20.0 GeV2. These studies indicate that the structure functions approximately scale in the variable ω, although significant deviations from scaling in ω are apparent in the region 1.3<ω<3.3. These deviations from scaling are in the same direction and of similar magnitude for both neutron and proton. The interpretation of the data in terms of various theoretical models is discussed.
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