Drell-Yan hadron tensor: contour gauge and gluon propagator

We consider the gauge invariant Drell-Yan hadron tensor which includes the standard and non-standard diagram contributions. The non-standard diagram contribution is appeared owing to the complexity of the twist three BV (x1;x2)-function where the gluon pole manifests. We use the contour gauge conception which allows us to fix easily the spurious uncertainties in the gluon propagator. The contour gauge condition is generated by the correspondingWilson lines in both the standard and non-standard diagrams. We demonstrate the substantial role of the non-standard diagram for forming of the relevant contour in theWilson path-ordered exponential that leads to the spurious singularity fixing