Twist expansion of differential cross-sections of forward Drell-Yan   process
  Forward Drell-Yan process at the LHC is a sensitive tool for investigating higher twist effects in QCD. The expansion of all Drell-Yan structure functions is performed assuming GBW saturation model and the saturation scale plays the role of the hadronic scale of OPE. We show that the Lam-Tung relation is broken at twist 4. The results open the way for a forthcoming analysis of multiple scattering and higher twist effects. 
Tomasz Stebel, Leszek Motyka and Mariusz Sadzikowski
hep-ph