Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces.
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
Posik, M; Flay, D; Parno, DS; Allada, K; Armstrong, W; Averett, T; Benmokhtar, F; Bertozzi, W; Camsonne, A; Canan, M; Cates, GD; Chen, C; Chen, J-P; Choi, S; Chudakov, E; Cusanno, F; Dalton, MM; Deconinck, W; de Jager, CW; Deng, X; Deur, A; Dutta, C; El Fassi, L; Franklin, GB; Friend, M; Gao, H; Garibaldi, F; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Gomez, J; Guo, L; Hansen, O; Higinbotham, DW; Holmstrom, T; Huang, J; Hyde, C; Ibrahim, HF; Jiang, X; Jin, G; Katich, J; Kelleher, A; Kolarkar, A; Korsch, W; Kumbartzki, G; LeRose, JJ; Lindgren, R; Liyanage, N; Long, E; Lukhanin, A; Mamyan, V; McNulty, D; Meziani, Z-E; Michaels, R; Mihovilovič, M; Moffit, B; Muangma, N; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Nuruzzaman, ; Oh, Y; Peng, JC; Qian, X; Qiang, Y; Rakhman, A; Riordan, S; Saha, A; Sawatzky, B; Shabestari, MH; Shahinyan, A; Širca, S; Solvignon, P; Subedi, R; Sulkosky, V; Tobias, WA; Troth, W; Wang, D; Wang, Y; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y-W; Zhao, B; Zheng, X; Jefferson Lab Hall A Collaboration,
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