Experimental Studies of Nucleon Structure: Commissioning Jefferson Lab Halls A and C

核子结构的实验研究：调试杰斐逊实验室 A 厅和 C 厅

• 批准号: 1508272
• 负责人: Michael Christy
• 金额: $ 22.5万
• 依托单位: Hampton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1508272&HistoricalAwards=false
• 关键词: Experimental; Studies; Nucleon; Structure; Commissioning

It is now a well-established fact that nucleons, protons and neutrons, are made up of more elementary particles called quarks. While the theory known as Quantum Chromodynamics (QCD) has become accepted as describing the strong interaction, which binds the constituent quarks and gluons in the nucleon, numerous questions still remain about the quark spatial and momentum distributions. The principle investigator and students will take a leading role in the first experiment to take place at Jefferson Lab after the recent upgrade, with the goal of measuring the quark spatial and momentum distributions in the nucleon, called the F_2 structure function. These distributions will be compared with predictions from models of the nucleon inspired by QCD theory. In addition to the scientific focus the research program will address a critical need for training of the next generation of physicists. As part of an Historically Black College or University, the graduate physics program at Hampton University broadly supports the education and training of both undergraduate and graduate studentsfrom this under-represented group. This project will continue to provide access to advanced, internationally-competitive, scientific training for these students.This research will study the transition from the momentum transfer region in which the quarks are asymptotically free to the region in which the quarks are bound into mesons and baryons. This will be accomplished through experiments to measure the proton magnetic form factor, GMp , and the F_2 inclusive structure function of the proton, neutron, and deuteron at large momentum transfer with significantly better precision than currently available. The project will additionally support required preparations for a later-to-run Hall B experiment to measure the F_2 structure function of the nearly free neutron in the poorly understood large x regime, and which was chosen by the Jefferson Lab Program Advisory Committee for the "High Impact" designation.

核子、质子和中子都是由更基本的夸克组成的，这一点现在已是公认的事实。虽然被称为量子色动力学（QCD）的理论已经被接受为描述强相互作用，它将夸克和胶子结合在核子中，但关于夸克的空间和动量分布仍然存在许多问题。主要研究者和学生将在杰斐逊实验室最近升级后的第一个实验中发挥主导作用，其目标是测量核子中的夸克空间和动量分布，称为F_2结构函数。 这些分布将与受QCD理论启发的核子模型的预测进行比较。除了科学重点，研究计划将解决下一代物理学家培训的关键需求。作为历史上黑人学院或大学的一部分，汉普顿大学的研究生物理课程广泛支持来自这一代表性不足的群体的本科生和研究生的教育和培训。本项目将继续为这些学生提供先进的、具有国际竞争力的科学培训。本研究将研究从夸克渐近自由的动量转移区域到夸克束缚成介子和重子的区域的过渡。这将通过测量质子磁形状因子GMp和质子、中子和氘核在大动量转移下的F_2结构函数的实验来实现，其精度比现有的要高得多。该项目还将支持稍后运行的霍尔B实验所需的准备工作，以测量几乎自由中子的F_2结构函数，在人们知之甚少的大x制度，这是由杰斐逊实验室计划咨询委员会选择的“高影响”指定。