Twist-3 quark-gluon correlation contribution to single-transverse spin   asymmetry for direct-photon and single-jet productions in pp collision
  We study the contribution of the collinear twist-3 quark-gluon correlation to the single transverse-spin asymmetry in direct-photon and single-jet productions in pp collision. At typical RHIC kinematics we find sizable asymmetries in the forward region of the polarized nucleon while they are almost zero in the backward region. We also find the soft-fermion pole contribution is vanishingly small, suggesting the measurement of these asymmetries provides us with an unique opportunity to determine the net soft-gluon pole function. 
Koichi Kanazawa and Yuji Koike
hep-ph hep-ex