학술논문
Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic Electron Scattering from $^{12}$C and $^{27}$Al
Document Type
Working Paper
Author
QWeak Collaboration; Androic, D.; Armstrong, D. S.; Asaturyan, A.; Bartlett, K.; Beminiwattha, R. S.; Benesch, J.; Benmokhtar, F.; Birchall, J.; Carlini, R. D.; Christy, M. E.; Cornejo, J. C.; Dusa, S. Covrig; Dalton, M. M.; Davis, C. A.; Deconinck, W.; Dowd, J. F.; Dunne, J. A.; Dutta, D.; Duvall, W. S.; Elassar, M.; Falk, W. R.; Finn, J. M.; Forest, T.; Gal, C.; Gaskell, D.; Gericke, M. T. W.; Gray, V. M.; Guo, F.; Hoskins, J. R.; Jones, D. C.; Kargiantoulakis, M.; King, P. M.; Korkmaz, E.; Kowalski, S.; Leacock, J.; Leckey, J. P.; Lee, A. R.; Lee, J. H.; Lee, L.; MacEwan, S.; Mack, D.; Magee, J. A.; Mahurin, R.; Mammei, J.; Martin, J. W.; McHugh, M. J.; Meekins, D.; Mesick, K. E.; Michaels, R.; Mkrtchyan, A.; Mkrtchyan, H.; Narayan, A.; Ndukum, L. Z.; Nuruzzaman; Nelyubin, V.; van Oers, W. T. H; Owen, V. F.; Page, S. A.; Pan, J.; Paschke, K. D.; Phillips, S. K.; Pitt, M. L.; Radloff, R. W.; Rajotte, J. F.; Ramsay, W. D.; Roche, J.; Sawatzky, B.; Seva, T.; Shabestari, M. H.; Silwal, R.; Simicevic, N.; Smith, G. R.; Solvignon, P.; Spayde, D. T.; Subedi, A.; Subedi, R.; Tadevosyan, V.; Tobias, W. A.; Waidyawansa, B.; Wang, P.; Wells, S. P.; Wood, S. A.; Zang, P.; Zhamkochyan, S.
Source
Phys. Rev. C 104, 014606 (2021)
Subject
Language
Abstract
We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of $B_n$ on $^{12}$C and provide a first measurement on $^{27}$Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average lab scattering angle for both targets was 7.7 degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561 GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppm for $^{12}$C and $B_n$ = -12.16 $\pm$ 0.58 (stat) $\pm$ 0.62 (syst) ppm for $^{27}$Al. The results are consistent with theoretical predictions, and are compared to existing data. When scaled by Z/A, the Q-dependence of all the far-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can be described by the same slope out to $Q \approx 0.35$ GeV. Larger-angle data from other experiments in the same Q range are consistent with a slope about twice as steep.
Comment: Minor changes after refereeing; version as accepted for Physical Review C. Cosmetic changes to several figures, one author added. 22 pages, 8 figures
Comment: Minor changes after refereeing; version as accepted for Physical Review C. Cosmetic changes to several figures, one author added. 22 pages, 8 figures