Abstract: The proton is a complex composite object. Its structure, the dynamics of its constituents, and its mass cannot be calculated from Quantum Chromo Dynamics (QCD) without simplifying model assumptions. Momentum- and spin-dependent distributions of quarks and gluons have been determined with increasing precision through 50 years of deep inelastic lepton-proton scattering experiments and the QCD analysis of 30 years of high-energy proton-proton collider data. Despite this significant effort, there remain important shortcomings in the knowledge of proton structure.
The seminar will review the present knowledge of transverse proton spin structure, introduce the Drell-Yan process, and summarize results from Drell-Yan experiments that aim to constrain transverse proton spin structure, sea-quarks, and nuclear effects. A focus of the talk will be future plans for Drell-Yan experiments with high-intensity meson and anti-proton beams at the CERN SPS.