Precision Measurements of \(A_1^n\) in the Deep Inelastic Regime

• Published in: arXiv.org 2019-08
• Main Authors: Parno, D S, Flay, D, Posik, M, Allada, K, Armstrong, W, Averett, T, Benmokhtar, F, Bertozzi, W, Camsonne, A, Canan, M, Cates, G D, Chen, C, J -P Chen, Choi, S, Chudakov, E, Cusanno, F, Dalton, M M, Deconinck, W, de Jager, C W, Deng, X, Deur, A, Dutta, C, L El Fassi, Franklin, G B, Friend, M, Gao, H, Garibaldi, F, Gilad, S, Gilman, R, Glamazdin, O, Golge, S, Gomez, J, Guo, L, Hansen, O, Higinbotham, D W, Holmstrom, T, Huang, J, Hyde, C, Ibrahim, H F, Jiang, X, Jin, G, Katich, J, Kelleher, A, Kolarkar, A, Korsch, W, Kumbartzki, G, LeRose, J J, Lindgren, R, Liyanage, N, Long, E, Lukhanin, A, Mamyan, V, McNulty, D, Z -E Meziani, Michaels, R, Mihovilovič, M, Moffit, B, Muangma, N, Nanda, S, Narayan, A, Nelyubin, V, Norum, B, Nuruzzaman, Y Oh, Peng, J C, Qian, X, Qiang, Y, Rakhman, A, Riordan, S, Saha, A, Sawatzky, B, Shabestari, M H, Shahinyan, A, Širca, S, Solvignon, P, Subedi, R, Sulkosky, V, Tobias, W A, Troth, W, Wang, D, Wang, Y, Wojtsekhowski, B, Yan, X, Yao, H, Y Ye, Z Ye, Yuan, L, Zhan, X, Zhang, Y, Y -W Zhang, Zhao, B, Zheng, X, The Jefferson Lab Hall A Collaboration
• Format: Article
• Language: English
• Subjects: Distribution functions; Inelastic scattering; Kinematics; Neutrons; Quarks
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1406.1207

We have performed precision measurements of the double-spin virtual-photon asymmetry \(A_1\) on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer. Our data cover a wide kinematic range \(0.277 \leq x \leq 0.548\) at an average \(Q^2\) 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 extract 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 \(A_1^n\) zero crossing near \(x=0.5\). We find no evidence of a transition to a positive slope in \((\Delta d + \Delta \bar{d})/(d + \bar{d})\) up to \(x=0.548\).