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

Hampton University, Hampton VA

Investigators

Abstract

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 students from 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.