Precision measurements of A1n in the deep inelastic regime

oleh: D.S. Parno, D. Flay, M. Posik, 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. Deng, A. 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

Format: Article
Diterbitkan: Elsevier 2015-05-01

Deskripsi

We have performed precision measurements of the double-spin virtual-photon asymmetry A1 on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized 3He target. Our data cover a wide kinematic range 0.277≤x≤0.548 at an average Q2 value of 3.078 (GeV/c)2, doubling the available high-precision neutron data in this x range. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in the same kinematic range. Our data are consistent with a previous observation of an A1n zero crossing near x=0.5. We find no evidence of a transition to a positive slope in (Δd+Δd¯)/(d+d¯) up to x=0.548. Keywords: Spin structure functions, Nucleon structure, Parton distribution functions, Polarized electron scattering