We study J/ψ survival probability, using short-distance QCD, in an equilibrating parton gas. The evolution of the system is determined within the Parton Cascade Model. Due to the formation of a large number of partons within this model, a large fraction of J/ψ are found to be suppressed. In a thermal equilibrating plasma this suppression is found to be almost 95 percent, while it is around 90 p...

We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms ...