Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering
Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering
复制标题
前角弹性电子质子散射中束流法线单自旋不对称性的精密测量
DOI：
10.1103/physrevlett.125.112502
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发表时间：
2020
影响因子：
8.6
通讯作者：
Carlini, R.D.
中科院分区：
文献类型：
--
作者：
Androic, D.;Armstrong, D.S.;Asaturyan, A;Bartlett, K.;Beaufait, J.;Beminiwattha, R.S.;Benesch, J.;Benmokhtar, F.;Birchall, J.;Carlini, R.D.
在横向极化的电子与未极化的核子的散射中产生的束流法线单自旋不对称是一个与双光子交换过程的虚部有关的可观测性。我们报道了平均散射角为1.149 GeV，平均能量为1.149 GeV的弹性电子-质子散射中束流法线单自旋不对称性的2%精度测量。不对称的结果是(系统)ppm。这是迄今为止对这一量进行的最精确的测量，因此在远向散射角()处对双光子交换模型进行了严格的测试，在该角度下它们应该是最可靠的。
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle ofand a mean energy of 1.149 GeV. The asymmetry result is(syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles () where they should be most reliable.