反应$^3$ He $^\uparrow(e,e^\prime)$准弹性散射中靶向单自旋不对称性的测量
Measurement of the Target-Normal Single-Spin Asymmetry in Quasi-Elastic Scattering from the Reaction $^3$He$^\uparrow(e,e^\prime)$
Y. -W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, W. Boeglin, P. Bradshaw, A. Camsonne, M. Canan, G. D. Cates,… 展开作者
Y. -W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, W. Boeglin, P. Bradshaw, A. Camsonne, M. Canan, G. D. Cates, C. Chen, J. P. Chen, E. Chudakov, R. De Leo, X. Deng, A. Deur, C. Dutta, L. El Fassi, D. Flay, S. Frullani, F. Garibaldi, H. Gao, S. Gilad, R. Gilman, O. Glamazdin, S. Golge, J. Gomez, O. Hansen, D. W. Higinbotham, T. Holmstrom, J. Huang, H. Ibrahim, C. W. de Jager, E. Jensen, X. Jiang, J. St. John, M. Jones, H. Kang, J. Katich, H. P. Khanal, P. King, W. Korsch, J. LeRose, R. Lindgren, H. -J. Lu, W. Luo, P. Markowitz, M. Meziane, R. Michaels, B. Moffit, P. Monaghan, N. Muangma, S. Nanda, B. E. Norum, K. Pan, D. Parno, E. Piasetzky, M. Posik, V. Punjabi, A. J. R. Puckett, X. Qian, Y. Qiang, X. Qiu, S. Riordan, G. Ron, A. Saha, B. Sawatzky, R. Schiavilla, B. Schoenrock, M. Shabestari, A. Shahinyan, S. Širca, R. Subedi, V. Sulkosky, W. A. Tobias, W. Tireman, G. M. Urciuoli, D. Wang, K. Wang, Y. Wang, J. Watson, B. Wojtsekhowski, Y. Ye, Z. Ye, X. Zhan, Y. Zhang, X. Zheng, B. Zhao, L. Zhu
We report the first measurement of the target single-spin asymmetry, $A_y$, in quasi-elastic scattering from the inclusive reaction $^3$He$^{\uparrow}(e,e^\prime)$ on a $^3$He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A non-zero $A_y$ can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the sub-structure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at $Q^{2}=$ 0.13, 0.46 and 0.97 GeV$^{2}$. These measurements demonstrate, for the first time, that the $^3$He asymmetry is clearly non-zero and negative with a statistical significance of (8-10)$σ$. Using measured proton-to-$^{3}$He cross-section ratios and the effective polarization approximation, neutron asymmetries of $-$(1-3)% were obtained. The neutron asymmetry at high $Q^2$ is related to moments of the Generalized Parton Distributions (GPDs). Our measured neutron asymmetry at $Q^2=0.97$ GeV$^2$ agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.
Physics Department, Brookhaven National Laboratory（布鲁克海文国家实验室）；RIKEN BNL Research Center, Brookhaven National Laboratory（布鲁克海文国家实验室）；Joint Institute for Nuclear Research（联合核研究所）
Transverse Single-Spin Asymmetry for Inclusive and Diffractive Electromagnetic Jets at Forward Rapidity in $p^{\uparrow}$+p Collisions at $\sqrt{s} = 200$ GeV and $510$ GeV at STAR
Study of Two-Photon Exchange via the Beam Transverse Single Spin Asymmetry in Electron-Proton Elastic Scattering at Forward Angles over a Wide Energy Range
Measurement of the Transverse Beam Spin Asymmetry in Elastic Electron Proton Scattering and the Inelastic Contribution to the Imaginary Part of the Two-Photon Exchange Amplitude
Nuclear dependence of the transverse single-spin asymmetry in the production of charged hadrons at forward rapidity in polarized $p+p$, $p+$Al, and $p+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV
