Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering and Drell-Yan Processes

Understand

We examine in detail the diagrammatic mechanisms which provide the change of sign between the single transverse spin asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY).

• This asymmetry is known to arise due to the transverse spin dependence of the target proton combined with a T-odd complex phase.
• Using the discrete symmetry properties of transverse spinors, we show that the required complex phase originates in the denominators of rescattering diagrams and their respective cuts.
• For simplicity, we work in a model where the proton consists of a valence quark and a scalar diquark.