Evidence for the t-quark in anti pp collider data

We propose a simple method to identify semileptonic weak decays t -> e#betta#b of any heavy particle t and to determine its mass independent of the t-production mechanism, using anti pp collider events that contain a single electron (or muon) and missing transverse momentum. Events with transverse mass Msub(T)(e#betta#) > 3 GeV originate either from t-decays of mass msub(t) > Msub(T)(e#betta#) + msub(b) or from W -> e#betta# decays; the latter is a distinctive background that can be subtracted. The Msub(T)(e#betta#) distribution of electron events with jets recently observed in the UA1 experiment at CERN may be interpreted as being due to a t-quark with mass 25 to 40 GeV. (orig.)