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 60, 100, 150, 180, and 20.60. These measurements were taken with 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 500 and 600 using the SLAC 1.6 GeV spectrometer, sharing beam and target. Combining large-angle data taken on the 1.6 GeV spectrometer with the data taken on the 20 GeV spectrometer enables separate determination of the proton structure functions sigma/sub L/ and sigma/sub T/ (or equivalently, νW2 and 2MW1). The data are consistent within systematic errors with earlier MIT-SLAC across section measurements. A combined data set for the experiments is constructed. From the combined data set an average value of sigma/sub L//sigma/sub T/ = .21 + .1 is determined over the kinematic range covered, 3 GeV2 < Q2 < 18 GeV2 and 4 GeV2 < W2 < 16 GeV2. The dependence of sigma/sub L//sigma/sub T/ on different kinematic variables is studied. The Q2 dependence is compared with theoretical predictions of quantum chromodynamics. The scaling behavior of the structure functions νW2 and 2MW1 is 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