基于宇称破缺电子散射测量首次确定27Al中子分布半径
核实验
2022-04-05 v2
摘要
我们报道了在27Al上宇称破缺弹性电子散射不对称的首次测量。27Al弹性不对称度为 A_PV = 2.16 ± 0.11 (统计) ± 0.16 (系统) ppm，在 Jefferson Lab 的 Qweak 装置上于 <Q^2> = 0.02357 ± 0.0001 GeV^2、<theta_lab> = 7.61 ± 0.02 度、<E_lab> = 1.157 GeV 处测得。使用简单 Born 近似以及更复杂的扭曲波计算给出的预测均与这一结果吻合良好。由该不对称度，采用多模型关联技术确定了27Al中子半径 R_n = 2.89 ± 0.12 fm。相应的中子皮厚度 R_n-R_p = -0.04 ± 0.12 fm 很小，正如仅含1个中子过剩的轻核所预期。因此该结果可作为在较重核上用电弱方法确定中子半径的成功基准。采用树级方法提取了27Al弱半径 R_w = 3.00 ± 0.15 fm，以及弱皮厚度 R_wk - R_ch = -0.04 ± 0.15 fm。该 Q^2 下的弱形状因子为 F_wk = 0.39 ± 0.04。
引用
@article{arxiv.2112.15412,
title = {First Determination of the 27Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement},
author = {QWeak Collaboration and D. Androic and D. S. Armstrong and K. Bartlett and R. S. Beminiwattha and J. Benesch and F. Benmokhtar and J. Birchall and R. D. Carlini and J. C. Cornejo and S. Covrig Dusa and M. M. Dalton and C. A. Davis and W. Deconinck and J. F. Dowd and J. A. Dunne and D. Dutta and W. S. Duvall and M. Elaasar and W. R. Falk and J. M. Finn and T. Forest and C. Gal and D. Gaskell and M. T. W. Gericke and V. M. Gray and K. Grimm and F. Guo and J. R. Hoskins and D. C. Jones and M. K. Jones and M. Kargiantoulakis and P. M. King and E. Korkmaz and S. Kowalski and J. Leacock and J. Leckey and A. R. Lee and J. H. Lee and L. Lee and S. MacEwan and D. Mack and J. A. Magee and R. Mahurin and J. Mammei and J. W. Martin and M. J. McHugh and D. Meekins and J. Mei and K. E. Mesick and R. Michaels and A. Micherdzinska and A. Mkrtchyan and H. Mkrtchyan and A. Narayan and L. Z. Ndukum and V. Nelyubin and Nuruzzaman and W. T. H van Oers and V. F. Owen and S. A. Page and J. Pan and K. D. Paschke and S. K. Phillips and M. L. Pitt and R. W. Radloff and J. F. Rajotte and W. D. Ramsay and J. Roche and B. Sawatzky and T. Seva and M. H. Shabestari and R. Silwal and N. Simicevic and G. R. Smith and P. Solvignon and D. T. Spayde and A. Subedi and R. Subedi and R. Suleiman and V. Tadevosyan and W. A. Tobias and V. Tvaskis and B. Waidyawansa and P. Wang and S. P. Wells and S. A. Wood and S. Yang and P. Zang and S. Zhamkochyan and M. E. Christy and C. J. Horowitz and F. J. Fattoyev and Z. Lin},
journal= {arXiv preprint arXiv:2112.15412},
year = {2022}
}
备注
Revised version after referee's comments and suggestions. Some improvements and clarification to the text, no changes to the figures, tables, results or conclusions. 7 pages, 3 figures, 3 tables