We present the results of a search for second generation leptoquarks $S_2$ using $19.3{\mathrm{pb}}^{-1\mathrm{}}$ of data collected at the Collider Detector at Fermilab (CDF) in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}$ TeV during the 1992–93 collider run. We have searched for $S_2\overline{S_2}$ pairs assuming that each leptoquark decays to a muon $+$ quark with a branching ratio $\beta$. We find two candidate events, consistent with an expected background of $1.11\pm 0.48$. We obtain upper limits on $\sigma (p\overline{p}\to S_2\overline{S_2}){\beta }^2$ as a function of $M_{S_2}$. Using a Monte Carlo prediction for $S_2\overline{S_2}$ pair production, we exclude $M_{S_2}<131\mathrm{GeV}/c^2$ for $\beta =1\mathrm{}$ and $M_{S_2}<96\mathrm{GeV}/c^2$ for $\beta =0.5\mathrm{}$ at 95% C.L.

• Received 21 March 1995

DOI:https://doi.org/10.1103/PhysRevLett.75.1012