Measurements of R = σL/σT for 0.03 < x < 0.1 and Fit to World Data

To be submitted to Physics Letters. SLAC-PUB-7927, August 1998Measurements were made at SLAC of the cross section for scattering 29 GeV electrons from carbon at a laboratory angle of 4.5◦, corresponding to 0.03 < x < 0.1 and 1.3 < Q2 < 2.7 GeV2. Values of R = σL/σT were extracted in this kinematic range by comparing these data to cross sections measured at a higher beam energy by the NMC collaboration. The results are in reason- able agreement with pQCD calculations and with extrapolations of the R1990 parameterization of previous data. A new fit is made including these data and other recent results.Work supported by Department of Energy contract DE–AC03–76SF00515

Measurements of the proton and deuteron spin structure function g<inf>2</inf> and asymmetry A<inf>2</inf>

We have measured proton and deuteron virtual photon-nucleon asymmetries A2p and A2d and structure functions g2p and g2d over the range 0.03 < x < 0.8 and 1.3 < Q2 < 10 (GeV/c)2 by inelastically scattering polarized electrons off polarized ammonia targets. Results for A2 are significantly smaller than the positivity limit √R for both targets. Within experimental precision the g2 data are well described by the twist-2 contribution, g2ww .Twist-3 matrix elements have been extracted and are compared to theoretical predictions.Link_to_subscribed_fulltex