$Q^2>1$ GeV $^2$的π介子独家电产生中的靶和束靶自旋不对称性。I. $e p \rightarrow e π^+ n$
Target and Beam-Target Spin Asymmetries in Exclusive Pion Electroproduction for $Q^2>1$ GeV$^2$. I. $e p \rightarrow e π^+ n$
P. E. Bosted, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, … 展开作者
P. E. Bosted, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, W. J. Briscoe, S. Bültmann, V. D. Burkert, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Clark, L. Colaneri, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, R. De Vita, A. Deur, E. De Sanctis, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J. A. Fleming, T. Forest, A. Fradi, N. Gevorgyan, G. P. Gilfoyle, F. X. Girod, C. Gleason, W. Gohn, E. Golovatch, R. W. Gothe, K. A. Griffioen, M. Guidal, H. Hakobyan, M. Hattawy, K. Hicks, M. Holtrop, S. M. Hughes, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, H. Jiang, H. S. Jo, K. Joo, S. Joosten, G. Khachatryan, M. Khandaker, A. Kim, W. Kim, F. J. Klein, S. Koirala, V. Kubarovsky, S. E. Kuhn, L. Lanza, L. A. Net, P. Lenisa, K. Livingston, I. J. D. MacGregor, M. E. McCracken, B. McKinnon, C. A. Meyer, M. Mirazita, V. I. Mokeev, R. A. Montgomery, E. Munevar, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, S. Niccolai, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, P. Peng, W. Phelps, S. Pisano, O. Pogorelko, J. W. Price, Y. Prok, D. Protopopescu, B. A. Raue, M. Ripani, G. Rosner, P. Rossi, R. A. Schumacher, Iu. Skorodumina, G. D. Smith, D. Sokhan, N. Sparveris, I. Stankovic, I. I. Strakovsky, S. Strauch, M. Taiuti, B. Torayev, M. Ungaro, H. Voskanyan, E. Voutier, X. Wei, L. B. Weinstein, J. Zhang, I. Zonta
备注：
27 pages, 11 figures, 1 supplemental data file. This version was submitted to Phys. Rev. C on October 7, 2016. arXiv admin note: substantial text overlap with arXiv:1604.04350
测量了排他性$π^+$电产生反应$γ^* p \to n π^+$的束靶双自旋不对称性和靶单自旋不对称性。这些结果是用杰斐逊实验室的CEBAF大型接收谱仪从6 GeV的纵向极化电子与纵向极化质子的散射中得到的。所涵盖的运动学范围是$1.1<W<3$ GeV和$1<Q^2<6$ GeV $^2$。在$W$、$Q^2$、$\cos(θ^*)$和$ϕ^*$中获得了约6000个箱的结果。除了在向前的角度，非常大的目标自旋不对称性观察到整个$W$区域。合理的协议被发现与现象学适合以前的数据为$W<1.6$ GeV，但非常大的差异被认为是在较高的$W$值。基于GPD的模型与数据的一致性较差。当结合横截面测量，目前的结果提供了强大的约束在中等和大的$Q^2$值的核子共振振幅，共振质量高达2.4 GeV。
英文摘要：
Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive $π^+$ electroproduction reaction $γ^* p \to n π^+$. The results were obtained from scattering of 6 GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Lab. The kinematic range covered is $1.1<W<3$ GeV and $1<Q^2<6$ GeV$^2$. Results were obtained for about 6000 bins in $W$, $Q^2$, $\cos(θ^*)$, and $ϕ^*$. Except at forward angles, very large target-spin asymmetries are observed over the entire $W$ region. Reasonable agreement is found with phenomenological fits to previous data for $W<1.6$ GeV, but very large differences are seen at higher values of $W$. A GPD-based model is in poor agreement with the data. When combined with cross section measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of $Q^2$, for resonances with masses as high as 2.4 GeV.
Hard exclusive pion electroproduction at backward angles with CLAS
我们报告的第一次测量的横截面独家深虚拟π电生产的质子，$e p \to e^\prime n π^+$，以上的共振区在向后π质心角。测量了$φ^*_π$依赖的截面，从中我们提取了质子的三种结构函数组合。我们的结果与基于核子到π介子跃迁分布振幅（TDAs）的计算结果是一致的，并为核子结构提供了新的解释。
Studying the Strangeness $D$-Term in Hall C via Exclusive $ϕ$ Electroproduction
Argonne National Laboratory（阿贡国家实验室）；A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute)（阿·伊·阿里哈尼扬国家科学实验室（耶烈万物理研究所））；Brookhaven National Laboratory（布鲁克海文国家实验室）；Florida International University（佛罗里达国际大学）；James Madison University（詹姆斯麦迪逊大学）；Jefferson Lab（杰斐逊实验室）；Old Dominion University（老道明大学）；Temple University（天普大学）；Mississippi State University（密西西比州立大学）；New Mexico State University（新墨西哥州立大学）；University of Regina（雷吉纳大学）；Southern University at New Orleans（新奥尔南南方大学）；Stony Brook University（石溪大学）；Department of Physics, Virginia Tech（弗吉尼亚理工大学物理系）；University of York（约克大学）
New Results from the Studies of the $N(1440)1/2^+$, $N(1520)3/2^-$, and $Δ(1620)1/2^-$ Resonances in Exclusive $ep \to e'p' π^+ π^-$ Electroproduction with the CLAS Detector
