The Spin Asymmetries of the Nucleon Experiment
Abstract
The spin structure functions of the proton have been measured for many years now. One kinematic region that suffers from a paucity of accurate data is x_bj>0.3 and Q^2 > 1.5 (GeV/c)^2. While measurements over the last few years at Jefferson Lab with the CEBAF Large Acceptance Spectrometer have measured the asymmetries for much of this large x_bj region with a longitudinally polarized target, we lack accurate data for transversely polarized targets. The transverse data is interesting in that it is more sensitive to higher twist contributions as seen through the g2 spin structure function. The Spin Asymmetries of the Nucleon Experiment (SANE) at Jefferson Lab, will measure inclusive transverse asymmetries over a wide kinematic region, 0.3<x_bj<1.0 and 2.5<Q^2<6.5. We will use the planned Big Electron Telescope Array (BETA) to detect the electrons scattered off a polarized NH3 target. BETA is based on a large Pb-Glass calorimeter coupled with detectors for particle identification. The data will provide the first comprehensive look at the kinematic dependence of g_2^p in x_bj and Q^2 and will enable us to determine higher ordered moments in both g_2^p and g_1^p. For example, we project that we can reduce the uncertainties on d2 as determined by the SLAC experiment 155x ( P.L. Anthony et al.), Phys. Lett. B 553, 18 (2003) by roughly one-half.
- Publication:
-
APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..DNP.BB012W