John Lajoie, Department of Physics and Astronomy
Spin-polarized deep-inelastic scattering in the late 1980's and early 1990's made a remarkable discovery, namely, that the spin of a proton was not carried predominantly by the constituent quarks. This discovery, often referred to as the "spin crisis", implied that the spin of a proton is generated by the dynamics of Quantum Chromodynamics (or QCD, the "strong" nuclear force). Because of this, we can use spin as a tool to further our understanding of bound systems of quarks in QCD. The PHENIX experiment at the Relativistic Heavy Ion Collider has an extensive physics program to study both transverse and longitudinally spin-polarized p+p collisions over a range of energies. In this presentation I will review what the PHENIX experiment has learned from the first ten years of operation of the world's only spin-polarized collider. I will also discuss the plans the PHENIX collaboration has been developing for the next decade of RHIC operations, where we will greatly extend the physics reach of spin measurements in polarized p+p collisions.