Induced polarization of Λ(1116) in kaon electroproduction
M. Gabrielyan, B. A. Raue, D. S. Carman, K. Park, K. P. Adhikari, D. Adikaram, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, J. Ball, N. A. Baltzell, M. Batta… 展开作者
M. Gabrielyan, B. A. Raue, D. S. Carman, K. Park, K. P. Adhikari, D. Adikaram, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, J. Ball, N. A. Baltzell, M. Battaglieri, V. Baturin, I. Bedlinskiy, A. S. Biselli, J. Bono, S. Boiarinov, W. J. Briscoe, W. K. Brooks, V. D. Burkert, T. Cao, A. Celentano, S. Chandavar, G. Charles, P. L. Cole, M. Contalbrigo, O. Cortes, V. Crede, A. DAngelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, D. Doughty, R. Dupre, L. El Fassi, P. Eugenio, G. Fedotov, S. Fegan, J. A. Fleming, T. A. Forest, B. Garillon, N. Gevorgyan, Y. Ghandilyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, E. Golovatch, R. W. Gothe, K. A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, M. Hattawy, K. Hicks, D. Ho, M. Holtrop, S. M. Hughes, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, D. Jenkins, H. Jiang, H. S. Jo, K. Joo, D. Keller, M. Khandaker, W. Kim, F. J. Klein, S. Koirala, V. Kubarovsky, S. E. Kuhn, S. V. Kuleshov, P. Lenisa, W. I. Levine, K. Livingston, I. J. D. MacGregor, M. Mayer, B. McKinnon, C. A. Meyer, M. D. Mestayer, M. Mirazita, V. Mokeev, C. I. Moody, H. Moutarde, A Movsisyan, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, S. Niccolai, G. Niculescu, M. Osipenko, L. L. Pappalardo, R. Paremuzyan, E. Pasyuk, P. Peng, W. Phelps, J. J. Phillips, S. Pisano, O. Pogorelko, S. Pozdniakov, J. W. Price, S. Procureur, D. Protopopescu, D. Rimal, M. Ripani, A. Rizzo, F. Sabatie, C. Salgado, D. Schott, R. A. Schumacher, A. Simonyan, G. D. Smith, D. I. Sober, D. Sokhan, S. S. Stepanyan, S. Stepanyan, I. I. Strakovsky, S. Strauch, V. Sytnik, W. Tang, M. Ungaro, A. V. Vlassov, H. Voskanyan, E. Voutier, N. K. Walford, D. P. Watts, X. Wei, L. B. Weinstein, N. Zachariou, L. Zana, J. Zhang
我们测量了反应$ep\rightarrow e'K^+Λ$中$Λ(1116)$的激发极化，探测到了最终态的散射$e'$和$K^+$以及来自$Λ\rightarrow pπ^-$衰变的质子。这允许在不变能量$W$中有较大的运动学接受度（$1.6\leq W \leq 2.7$ GeV），并覆盖了平均动量转移$Q^2=1.90$ GeV $^2$的K介子产生角的全部范围。我们已经绘制出的$W$和K介子生产角度的依赖性的诱导极化，并发现显着的差异，从光生数据在大部分的运动学范围内研究。然而，我们还发现，在我们的运动学域中，激发极化基本上是$Q^2$独立的，这表明在这里覆盖的$Q^2$以下的某个地方，必须有一个很强的$Q^2$依赖性。随着以前公布的光和电产生横截面和偏振观测值，这些数据是需要的模型，如有效场理论的发展，并作为输入耦合通道分析，可以提供以前未观察到的$s$通道共振的证据。
英文摘要：
We have measured the induced polarization of the $Λ(1116)$ in the reaction $ep\rightarrow e'K^+Λ$, detecting the scattered $e'$ and $K^+$ in the final state along with the proton from the decay $Λ\rightarrow pπ^-$.The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy $W$ ($1.6\leq W \leq 2.7$ GeV) and covered the full range of the kaon production angle at an average momentum transfer $Q^2=1.90$ GeV$^2$.In this experiment a 5.50 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. We have mapped out the $W$ and kaon production angle dependencies of the induced polarization and found striking differences from photoproduction data over most of the kinematic range studied. However, we also found that the induced polarization is essentially $Q^2$ independent in our kinematic domain, suggesting that somewhere below the $Q^2$ covered here there must be a strong $Q^2$ dependence. Along with previously published photo- and electroproduction cross sections and polarization observables, these data are needed for the development of models, such as effective field theories, and as input to coupled-channel analyses that can provide evidence of previously unobserved $s$-channel resonances.
Probing hard/soft factorization via beam-spin asymmetry in exclusive pion electroproduction from the proton
University of Regina（里贾纳大学）；Thomas Jefferson National Accelerator Facility（托马斯·杰斐逊国家加速器设施）；Catholic University of America（美利坚天主教大学）；University of York（约克大学）；Florida International University（佛罗里达国际大学）；Ohio University（俄亥俄大学）；Research Institute of Basic Sciences, Korea Aerospace University（韩国航空大学基础科学研究院）；Department of Physics, Yonsei University（延世大学物理系）
