Investigating the Electromagnetic Structure of the Nucleon and Light Nuclei at Jefferson Lab

该研究项目的主要目标是继续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(“杰斐逊实验室”)进行合作，专门针对使用高能电子束探测核子结构。这项工作将与杰斐逊实验室A厅的超级大比特光谱仪(SBS)合作完成。在此授权期内，杰斐逊实验室将走出过去的过渡“升级期”--将束流能量从6GeV升级到12GeV--并开始使用专门为更高能量设计和制造的设备。这项提议包括一项计划，以确保继续作出科学贡献，并通过早期运行的霍尔A实验(不仅侧重于核子结构，而且侧重于轻核--特别是Triton三核子系统的实验)培训学生，但主要重点仍然是与一系列具体的后来运行的SBS实验有关的准备/开发项目，这些实验将以非常高的动量转移探索核子结构功能。这个项目所有方面的主要物理目标都与提高对从相对较大的距离尺度(大约1到几个费米(其中强子自由度最合适)的“强(非微扰)QCD”体制)到短得多距离尺度的“微扰QCD”体制的理解有关。

The primary objective of this research project is to continue collaborative efforts at the Thomas Jefferson National Accelerator Facility ("Jefferson Lab") in Newport News, Virginia, which are specifically aimed at probing the structure of the nucleon using a high energy electron beam. This work will be accomplished in collaboration with the Super BigBite Spectrometer (SBS) Collaboration in Hall A at Jefferson Lab. During this grant period, Jefferson Lab will be emerging from the past transition "upgrade period" phase - having upgraded the beam energy from 6 GeV to 12 GeV - and beginning to utilize equipment specifically designed and built for the higher energy. This proposal includes a plan to ensure continued scientific contributions and student training with the early-running Hall A experiments (experiments focusing not only on nucleon structure, but also on that of light nuclei - particularly the triton three-nucleon system), but with primary emphasis remaining on preparation/development projects associated with a series of specific later-running SBS experiments that will probe nucleon structure functions at very high momentum transfers. The driving physics goals of all aspects of this project are related to improving understanding of the transition from the 'strong (non-perturbative) QCD' regime of relatively large distance scales of approximately 1 to a few fermis (where hadronic degrees of freedom are most appropriate), to the 'perturbative QCD' regime of much shorter distance scales.