Position Space Interpretation for Generalized Parton Distributions

connection with ⊥ SSA
example: γp → πX (Breit frame)
⃗p γ ⃗p N d
π +
u, d distributions in ⊥ polarized proton have left-right asymmetry in
⊥ position space (T-even!); sign determined by κ u & κ d
attractive FSI deflects active quark towards the center of
momentum
↩→ FSI converts left-right position space asymmetry of leading quark
into right-left asymmetry in momentum
compare: convex lens that is illuminated asymmetrically
↩→ semi-classical picture for recent results by Brodsky et al.
natural explanation for correlation between sign of κ q and sign of
SSA
u
Position Space Interpretation for Generalized Parton Distributions – p.23/55