Search for $\mathrm{Charge}-1/3$ Third-Generation Leptoquarks in $\mathit{p}\overline{p}\mathit{}$ Collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$

We report on a search for $\mathrm{charge}-1/3$ third-generation leptoquarks (LQ) produced in $p\overline{p}$ collisions at $\surd s=1.8\mathrm{}\mathrm{TeV}$ using the $\mathrm{D}0$ detector at Fermilab. Third-generation leptoquarks are assumed to be produced in pairs and to decay to a tau neutrino and a $b$ quark with branching fraction $B$. We place upper limits on $\sigma (p\overline{p}\to \mathrm{LQ}\overline{\mathrm{LQ}})B^2$ as a function of the leptoquark mass $M_{\mathrm{LQ}}$. Assuming $B=1\mathrm{}$, we exclude at the 95% confidence level third-generation scalar leptoquarks with $M_{\mathrm{LQ}}<94\mathrm{}\mathrm{GeV}{/c}^2$, and third-generation vector leptoquarks with $M_{\mathrm{LQ}}<216\mathrm{}\mathrm{GeV}{/c}^2(M_{\mathrm{LQ}}<148\mathrm{}\mathrm{GeV}{/c}^2$) assuming Yang-Mills (anomalous) coupling.