Toponium production at future hadron colliders is investigated. Perturbative QCD corrections to the production cross section for gluon fusion are calculated as well as the contributions from gluon-quark and quark-antiquark collisions to the total cross section. The dependence on the renormalization and factorization scales and on the choice of the parton distribution functions is explored. QCD corrections to the branching ratio of ${\eta }_t$ into $\gamma \gamma$ are included and the two-loop QCD potential is used to predict the wave function at the origin. The branching ratio of ${\eta }_t$ into $\gamma Z$, $\mathrm{ZZ}$, $\mathrm{HZ}$, and $\mathrm{WW}$ is compared with the $\gamma \gamma$ channel.

• Received 21 December 1992

DOI:https://doi.org/10.1103/PhysRevD.48.179