Quark Correlations and Single Spin Asymmetries

We analyze the Sivers asymmetry in light-cone gauge. The average transverse momentum of the quark distribution is related to the correlation between the quark distribution and the transverse component of the gauge field at $x^-\pm \infty$. We then use finiteness conditions for the light-cone Hamiltonian to relate the transverse gauge field at $x^{-}=\pm \mathrm{\infty }$ to the color density integrated over $x^{-}$. This result allows us to relate the average transverse momentum of the active quark to color charge correlations in the transverse plane.