Inelastic Physics Asymmetries

Dr. Tony Forest
Idaho State University
Department of Physics
Jefferson National Laboratory

ISU's intermediate energy nuclear physics group is presently involved in several fundamental physics measurements.  This talk will describe two measurements that use inelastic polarized electron scattering.  The first measurement investigates the response of the nucleon's first excited state, the Delta resonance, to polarized electro-magnetic probes.  The excitation of the nucleon to its first excited state is commonly described in terms of a quark spin flip induced by an electromagnetic probe.  Recently, however, there has been increasing interest in a second method that uses a  different neutral particle called the Z-boson to induce the quark spin flip via the Weak force.  A fundamental constant known as d-delta can be measured using this interaction.  A second program to measure quark polarization distributions by looking at the response of a polarized nucleon to a polarized electron is also underway.  This program will test the predictions of a fundamental theory known as quantum-chromodynamics.  The physics implications of these experiments and the roles of graduate students in the physics program will be described.