| Experiments at Jefferson Lab have been conducted to extract the nucleon spin-dependent structure functions over a wide kinematic range. Higher moments of these quantities provide tests of QCD sum rules and predictions of chiral perturbation theory (chiPT). While precise measurements of g n1, gn2, and gp1 have been extensively performed, the data of gn2 remain scarce. Discrepancies were found between existing data related to g 2 and theoretical predictions. Results on the proton at large Q2 show a significant deviation from the Burkhardt-Cottingham sum rule, while results for the neutron generally follow this sum rule. The next-to-leading order chiPT calculations exhibit discrepancy with data on the longitudinal-transverse polarizability delta nLT. Further measurements of the proton spin structure function gp2 are desired to understand these discrepancies.;Experiment E08-027 (g2p) was conducted at Jefferson Lab in experimental Hall A in 2012. Inclusive measurements were performed with polarized electron beam and a polarized ammonia target to obtain the proton spin-dependent structure function gp2 at low Q2 region (0.02 |
