Spin Observables in Hadron Spectroscopy

高能光子的散射已经被研究了几十年。对这一努力的长期兴趣在很大程度上是由对核子和介子激发的研究推动的，核子和介子激发表现为夸克的特定配置或胶子激发。强相互作用理论预测了介子中将夸克和反夸克紧密结合在一起的胶水的激发，但尚未从实验上证实。正在弗吉尼亚州纽波特纽斯的托马斯·杰斐逊国家加速器设施(JLab)建造的GlueX实验将致力于寻找这种激发。通过使用高能、高偏振的光子束和具有全角覆盖的高分辨率探测器，GlueX实验预定解决这一问题。通过美国国家科学基金会的支持，CUA能够继续为本实验建造和维护宽带标记示波器和偏振光子源。此外，多年来，在JLab的偏振目标计划中，CUA一直是领先的机构，旨在以偏振可观测的形式测量散射幅度的所有分量，从而明确地区分对散射的共振贡献。NSF提供的拨款还将支持CUA继续努力分析JLab B厅的冷冻自旋目标数据。他们的研究旨在解决我们对由夸克和胶子组成的核物质的长期理解问题。为此，他们开发了最先进的设备和先进的软件包。学生和博士后研究人员强烈参与了这一努力。他们在专业指导下接受的培训将加强他们的分析能力，并为他们在现代技术社会中担任负责任的领导职位做好准备。

The scattering of high-energetic photons has been studied for many decades. The long interest in this endeavor is largely motivated by the study of nucleon and meson excitations, which manifest themselves as specific configurations of quarks or as gluonic excitation. The excitation of the glue that holds quarks and antiquarks closely together in mesons is predicted by the theory of strong interaction but has not been experimentally established. The GlueX experiment being constructed at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, VA, will be devoted to the search for such excitation. By using a high-energetic, highly polarized photon beam and a high-resolution detector with complete angular coverage, the GlueX experiment is predetermined to settle the question. Through NSF support, CUA is able to proceed with constructing and maintaining the broad-band tagging hodoscope and the polarized photon source for this experiment. Moreover, for many years CUA has been a leading institution in the polarized target program at JLab, aimed to measure all components of the scattering amplitudes in form of polarization observables, and thus to disentangle unambiguously the resonant contributions to the scattering. The grant provided by NSF will also support CUA's continuing efforts in the analysis of data taken on frozen-spin targets in JLab's Hall B.Their research aims for settling long-standing questions in our understanding of nuclear matter, which is comprised of quarks and gluons. To this end they develop state-of-the-art equipment and advanced software packages. Students and postdoctoral researchers are strongly involved in this effort. Their training under professional guidance will strengthen their analytical competence and prepare them for responsible and leading positions in the modern technological society.