Superstring-inspired ${\mathrm{E}}_6$ models suggest the existence of scalar leptoquarks, $\tilde{D}$ and ${\tilde{D}}^{c*}$, with fractional charge and color interactions. These particles can be produced in hadron collisions via their Yukawa couplings to a quark and an electron. We analyze the production of a single scalar leptoquark in future $\mathrm{pp}$ and $p\overline{p}$ colliders assuming various couplings and leptoquark masses. Soft-gluon corrections, namely, ${\pi }^2$ terms, are estimated. They lead to an enhancement of the cross section by a significant factor, as well as an increase in the signal-to-background ratio.

• Received 13 February 1989

DOI:https://doi.org/10.1103/PhysRevD.40.2869