Search for new heavy quarks in electron-muon events at the Fermilab Tevatron Collider

A search for tt»e1/4+X in pp» collisions at ss» TeV is described. The production and decay of top-quarke"antiquark pairs is considered in the context of the standard model. The analysis is based on data with an integrated luminosity of 4.4 pb-1 recorded with the Collider Detector at Fermilab. An upper limit on the tt» cross section is obtained, and the top quark in the mass range 28e"72 GeV/c2 is excluded at the 95% C.L. The same limits apply to a possible fourth-generation, charge -(1/3, be quark, decaying via the charged current. © 1990 The American Physical Society.