| Abstrakt: |
We propose to measure the semi-inclusive double-spin asymmetries in deep-inelastic pvector (evector ,e′h)X and dvector (evector ,e′h)X reactions (h = π+, π-, K+ and K-) on longitudinally polarized NH3 and LiD targets. The high statistic data will allow a leading order five-flavor decomposition (Δu, Δd, Δū, Δd, Δs = Δs) of the nucleon spin structure in the region of x = 0.12 ∼ 0.43 at a Q2 of 1.21 ∼ 3.22 GeV2. The combined spin dependent π+ + π- yield ratios will be measured, since the acceptance and the hadron efficiencies of the detectors can be accurately determined. Independent of fragmentation functions and parton distributions, the z-dependence (z = 0.38 ∼ 0.71) of the combined ratios provides a build-in test of factorization at the moderate Q2. We estimate statistical uncertainties associated with such measurements. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR] |
