论文标题
前角弹性电子散射中光束正常单旋不对称的精确测量
Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering
论文作者
论文摘要
从非极化核子横向极化电子散射中产生的光束正态旋转不对称是与两光子交换过程的假想部分相关的可观察到的。我们报告了弹性电子普罗替子散射中梁正常单旋不对称的2%精度测量,其平均散射角度为theta_lab = 7.9度,平均能量为1.149 GEV。不对称结果为b_n = -5.194 +-0.067(stat) +-0.082(Syst)ppm。这是迄今为止可用的该数量的最精确的测量,因此在遥远的散射角(theta_lab-> 0)对两光子交换模型进行了严格的测试,其中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 of theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_n = -5.194 +- 0.067 (stat) +- 0.082 (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 (theta_lab -> 0) where they should be most reliable.