Heavy Quarkonium Production in Single Transverse Polarized High Energy Scattering

Understand

We formulate the single transverse spin asymmetry in heavy quarkonium production in lepton-nucleon and nucleon-nucleon collisions in the non-relativistic limit.

• We find that the asymmetry is very sensitive to the production mechanism.
• The final state interactions with the heavy quark and antiquark cancel out among themselves when the pair are produced in a color-single configuration, or cancel out with the initial state interaction in pp scattering when they are in color-octet.
• As a consequence, the asymmetry is nonzero in ep collisions only in the color-octet model, whereas in pp collisions only in the color-singlet model.