Search for Second-Generation Leptoquark Pairs in p̄p Collisions at √s = 1.8 TeV

We have searched for second-generation leptoquark (LQ) pairs in the mm+jets channel using 94+/-5 pb(-1) of pp collider data collected by the D0 experiment at the Fermilab Tevatron during 1993-1996. No evidence for a signal is observed. These results are combined with those from the mnu+jets and nunu+jets channels to obtain 95% confidence level (C.L.) upper limits on the LQ pair production cross section as a function of mass and beta, the branching fraction of a LQ decay into a charged lepton and a quark. Lower limits of 200(180) GeV/c(2) for beta = 1(1 / 2) are set at the 95% C.L. on the mass of scalar LQ. Mass limits are also set on vector leptoquarks as a function of beta.