Contribution superstring Z' boson on the polarization effects in   proton-proton collisions
  In this work we investigate the single- and the double- spin asymmetries at the collisions of polarized protons $pp \to (\gamma*, Z^0,Z')+X within the scope of QCD, electroweak interaction and superstring E_6 theory. The helicity amplitude method is used. Analytical expressions for the single- and the double- spin asymmetries are obtained and their dependence from the transverse momentum of lepton pair is investigated at the three different values of invariant masses of lepton pair. Has been extracted pure contribution coming from superstring Z' boson on the single- and double- spin asymmetries. The obtained results allow to investigate the spin structure of the proton. 
R.Kh.Muradov and A.I.Ahmadov