Measurement of the proton structure functions using inelastic electron scattering

Measurements of inclusive electron scattering cross sections from hydrogen are reported for beam energies between 6.5 GeV and 19.5 GeV and for electron scattering angles of 6, 10, 15, 18, and 20.60. These measurements were taken using the Stanford Linear Accelerator and the 20 GeV spectrometer. Details of the experiment and the analysis are presented along with an estimate of the systematic errors on the cross section. The data were taken simultaneously (but not in coincidence) with similar measurements at 50 and 600 using the SLAC 1.6 GeV spectrometer, sharing beam target. By combining large angle data taken on the 1.6 GeV spectrometer with the data taken on the 20 GeV spectrometer, the proton structure functions sigma/sub L/ and sigma/sub T/ (or equivalently, νW2 and 2MW1) were able to be separately determined. It was determined that data are consistent within systematic errors with earlier MIT-SLAC cross section measurements. A combined data set for the experiments was constructed. From the combined data set an average value of sigma/sub L//sigma/sub T/ = 0.21 +- 0.1 over the kinematic range covered, 3 GeV2 < Q2 < 18 GeV2 and 4 GeV2 < W2 < 16 GeV2 was determined. The dependence of sigma/sub L//sigma/sub T/ on different kinematic variables was studied. The Q2 dependence was compared with theoretical predictions on quantum chromodynamics. The scaling behavior of the structure functions νW2 and 2MW1 was investigated. The values of νW2 and 2MW1 are evaluated along contours for which the scaling variables are constants. The Q2 dependence along such contours is determined and agrees qualitatively with the predictions of asymptotically free gauge theories. 1 reference