Physics Letters B ( IF 4.4 ) Pub Date : 2021-11-25 , DOI: 10.1016/j.physletb.2021.136798 T. Kolar , S.J. Paul , P. Achenbach , H. Arenhövel , A. Ashkenazi , J. Beričič , R. Böhm , D. Bosnar , T. Brecelj , E. Cline , E.O. Cohen , M.O. Distler , A. Esser , I. Friščić , R. Gilman , C. Giusti , M. Heilig , M. Hoek , D. Izraeli , S. Kegel , P. Klag , I. Korover , J. Lichtenstadt , I. Mardor , H. Merkel , D.G. Middleton , M. Mihovilovič , J. Müller , U. Müller , M. Olivenboim , E. Piasetzky , J. Pochodzalla , G. Ron , B.S. Schlimme , M. Schoth , F. Schulz , C. Sfienti , S. Širca , R. Spreckels , S. Štajner , Y. Stöttinger , S. Strauch , M. Thiel , A. Tyukin , A. Weber , I. Yaron
We present measurements of the electron helicity asymmetry in quasi-elastic proton knockout from 2H and 12C nuclei by polarized electrons. This asymmetry depends on the fifth structure function, is antisymmetric with respect to the scattering plane, and vanishes in the absence of final-state interactions, and thus it provides a sensitive tool for their study. Our kinematics cover the full range in off-coplanarity angle , with a polar angle coverage up to about 8°. The missing energy resolution enabled us to determine the asymmetries for knock-out resulting in different states of the residual 11B system. We find that the helicity asymmetry for p-shell knockout from 12C depends on the final state of the residual system and is relatively large (up to ≈0.16), especially at low missing momentum. It is considerably smaller (up to ≈0.01) for s-shell knockout from both 12C and 2H. The data for 2H are in very good agreement with theoretical calculations, while the predictions for 12C exhibit differences with respect to the data.
中文翻译:
准弹性 A(e→,e′p) 过程中电子螺旋度不对称性的测量
我们展示了通过极化电子从2 H 和12 C 核中敲除准弹性质子中电子螺旋度不对称性的测量结果。这种不对称性取决于第五结构函数,相对于散射平面是反对称的,并且在没有终态相互作用的情况下消失,因此它为他们的研究提供了一个敏感的工具。我们的运动学涵盖了偏离共面角的全部范围, 极角 覆盖范围可达约 8°。缺失的能量分辨率使我们能够确定敲除的不对称性,导致残余11 B 系统的不同状态。我们发现从12 C敲除p壳层的螺旋度不对称性取决于残差系统的最终状态,并且相对较大(高达 ≈0.16),尤其是在低动量缺失时。它是相当小的(高达≈0.01),用于小号-shell敲除来自12 C和2 H.用于数据2 H的在与理论计算非常一致,而预测为12相对于Ç表现出的差异的数据.