Color Transfer in Associated Heavy-Quarkonium Production

TL;DR

This paper investigates heavy quarkonium production alongside a heavy quark pair, highlighting unique non-relativistic phase space effects and color exchange phenomena not captured by standard effective theories.

Contribution

It identifies a novel phase space region with low relative velocities where infrared sensitive color exchange occurs, extending understanding beyond existing effective field theory approaches.

Findings

Infrared sensitive color exchange depends on unpaired quark presence.

Effect diminishes as particles become relativistic.

No such effect for massless quarks or gluons.

Abstract

We study the production of heavy quarkonium in association with an additional heavy pair. We argue that important contributions may come from phase space regions where three heavy fermions are separated by relative velocities much lower than the speed of light, and to which standard effective field theories do not apply. In this region, infrared sensitive color exchange is specific to the presence of the unpaired (anti)quark. This effect vanishes as the motion of the additional particle becomes relativistic with respect to the pair, and is completely absent for massless quarks and gluons in the final state.