Nucleon Structure and Nuclear Force Studies

Kent State University, Kent OH

Investigators

Abstract

This award is for support for a group of researchers at Kent State University to perform work in experimental medium-energy nuclear physics. The goals of this research include determining the origin of the intrinsic angular momentum, or spin, of the proton, measuring the charge distribution inside the neutron, and studying short-range correlations in the nuclear force inside nuclei. The work to study the origin of the spin of the proton will be performed as part of the STAR detector collaboration at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The measurements of the charge distribution inside the neutron and the study of nuclear short-range correlations will be performed at the Jefferson National Accelerator Facility (JLab). The research to be performed builds on the strength and experience of this group using large-volume neutron detectors and measuring asymmetries of particles emitted in nuclear reactions. The measured asymmetries of emitted particles in high-energy proton-proton collisions with the STAR detector at RHIC will allow one to determine the contributions of gluons to the spin of the proton. Gluons are the exchange particle responsible for the force between the quarks that make up the proton. The gluon contribution to the spin of the proton can be determined only from collisions of polarized (spin aligned) protons. This group has contributed elements to a new end-cap calorimeter for the STAR detector that will allow better measurements of the particle asymmetries. The measurements of the charge distribution of the neutron and of nuclear short-range correlations at JLab involve the use of large-volume, fast neutron detector arrays developed by this group over a number of years. All of these measurements will provide an increased understanding of the structure of the nucleon and the nature of the nuclear force. This work will provide also critically needed training of doctoral-level physicists needed in modern industry, medical fields, and academia.