The RHIC Spin Program: Achievements and Future Opportunities

Understand

This document summarizes recent achievements of the RHIC spin program and their impact on our understanding of the nucleon's spin structure, i.e.

• the individual parton (quark and gluon) contributions to the helicity structure of the nucleon and to understand the origin of the transverse spin phenomena.
• Open questions are identified and a suite of future measurements with polarized beams at RHIC to address them is laid out.
• Machine and detector requirements and upgrades are briefly discussed.