Hadron Spin Polarization - where the Spin-Orbit Interaction?

The hadron polarization induced by the high energy hadron collisions seemed to have been well established as its origin for producing the spin asymmetry is the spin-orbit interaction. However after one theoretical work which indicated a failour of the spin-orbit interaction to provide correct p_T dependence of the spin polarizations, its genuine origin to creat spin asymmetry distributions became obscure. We discuss here intuitively and numerically what kind of spin-orbit we should argue for origin of the spin polarizations and we solve the existing confusions.