Large - Distance Effects in QCD and Spin Asymmetries in Diffractive Reactions

Abstract

Large - distance effects in the hadron wave function for the hadron-Pomeron vertex in the QCD -model are discussed. It is shown that they lead to the spin-flip part of the Pomeron coupling which can reach $10 \div 20 %$ with respect to the non-flip part. The obtained structure of the Pomeron coupling modifies spin asymmetries in high--energy diffractive reactions where the Pomeron structure becomes determinative. We study spin asymmetries in exclusive reactions and in the diffractive $Q \bar Q$ and $J/\Psi$ production. We have found that spin effects in these diffractive processes are sensitive to the spin-flip part of the Pomeron coupling.