Unitarization of gluon exchange amplitudes and rapidity gaps at the Fermilab Tevatron

Abstract

Rapidity gaps between two hard jets at the Fermilab Tevatron have been interpreted as being due to the exchange of two gluons which are in an overall color-singlet state. We show that this simple picture involves unitarity violating amplitudes. Unitarizing the gluon exchange amplitude leads to qualitatively different predictions for the fraction of $t$-channel color singlet exchange events in forward $qq,$ $\mathrm{qg}$ or $\mathrm{gg}$ scattering, which better fit Tevatron data.