학술논문
First Determination of the 27Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement
Document Type
Working Paper
Author
QWeak Collaboration; Androic, D.; Armstrong, D. S.; Bartlett, K.; Beminiwattha, R. S.; Benesch, J.; Benmokhtar, F.; Birchall, J.; Carlini, R. D.; 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.; Elaasar, M.; Falk, W. R.; Finn, J. M.; Forest, T.; Gal, C.; Gaskell, D.; Gericke, M. T. W.; Gray, V. M.; Grimm, K.; Guo, F.; Hoskins, J. R.; Jones, D. C.; Jones, M. K.; Kargiantoulakis, M.; King, P. M.; Korkmaz, E.; Kowalski, S.; Leacock, J.; Leckey, J.; 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.; Mei, J.; Mesick, K. E.; Michaels, R.; Micherdzinska, A.; Mkrtchyan, A.; Mkrtchyan, H.; Narayan, A.; Ndukum, L. Z.; Nelyubin, V.; Nuruzzaman; 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.; Suleiman, R.; Tadevosyan, V.; Tobias, W. A.; Tvaskis, V.; Waidyawansa, B.; Wang, P.; Wells, S. P.; Wood, S. A.; Yang, S.; Zang, P.; Zhamkochyan, S.; Christy, M. E.; Horowitz, C. J.; Fattoyev, F. J.; Lin, Z.
Source
Phys. Rev. Lett. 128, 13250 (2022)
Subject
Language
Abstract
We report the first measurement of the parity-violating elastic electron scattering asymmetry on 27Al. The 27Al elastic asymmetry is A_PV = 2.16 +- 0.11 (stat) +- 0.16 (syst) ppm, and was measured at =0.02357 +- 0.0001 GeV^2, = 7.61 +- 0.02 degrees, and = 1.157 GeV with the Qweak apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the 27Al neutron radius R_n = 2.89 +- 0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_n-R_p = -0.04 +- 0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the 27Al weak radius R_w = 3.00 +- 0.15 fm, and the weak skin thickness R_wk - R_ch = -0.04 +- 0.15 fm. The weak form factor at this Q^2 is F_wk = 0.39 +- 0.04.
Comment: 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
Comment: 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