Precision measurement of the neutron twist-3 matrix element d2n: Probing color forces

M. Posik, D. Flay, D. S. Parno, K. Allada, W. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, G. D. Cates, C. Chen, J. P. Chen, S. Choi, E. Chudakov, F. Cusanno, M. M. Dalton, W. Deconinck, C. W. De Jager, X. DengA. Deur, C. Dutta, L. El Fassi, G. B. Franklin, M. Friend, H. Gao, F. Garibaldi, S. Gilad, R. Gilman, O. Glamazdin, S. Golge, J. Gomez, L. Guo, O. Hansen, D. W. Higinbotham, T. Holmstrom, J. Huang, C. Hyde, H. F. Ibrahim, X. Jiang, G. Jin, J. Katich, A. Kelleher, A. Kolarkar, W. Korsch, G. Kumbartzki, J. J. Lerose, R. Lindgren, N. Liyanage, E. Long, A. Lukhanin, V. Mamyan, D. McNulty, Z. E. Meziani, R. Michaels, M. Mihovilovič, B. Moffit, N. Muangma, S. Nanda, A. Narayan, V. Nelyubin, B. Norum, Nuruzzaman, Y. Oh, J. C. Peng, X. Qian, Y. Qiang, A. Rakhman, S. Riordan, A. Saha, B. Sawatzky, M. H. Shabestari, A. Shahinyan, S. Širca, P. Solvignon, R. Subedi, V. Sulkosky, W. A. Tobias, W. Troth, D. Wang, Y. Wang, B. Wojtsekhowski, X. Yan, H. Yao, Y. Ye, Z. Ye, L. Yuan, X. Zhan, Y. Zhang, Y. W. Zhang, B. Zhao, X. Zheng

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


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 He3 target. In this dedicated experiment, the spin structure function g2He3 was determined with precision at large x, and the neutron twist-3 matrix element d2n was measured at 〈Q2〉 of 3.21 and 4.32GeV2/c2, 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 〈Q2〉=5GeV2/c2. Combining d2n and a newly extracted twist-4 matrix element f2n, the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30MeV/fm in magnitude.

Original languageEnglish
Article number022002
JournalPhysical Review Letters
Issue number2
StatePublished - Jul 11 2014

ASJC Scopus subject areas

  • General Physics and Astronomy


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