  Events with isolated leptons play a prominent role in signatures of new
physics phenomena at high energy collider physics facilities. In earlier
publications, we examine the standard model contribution to isolated lepton
production from bottom and charm mesons and baryons through their semileptonic
decays (b, c -> l + X), showing that this source can overwhelm the effects of
other standard model processes in some kinematic domains. In this paper, we
show that we obtain good agreement with recent Tevatron collider data, both
validating our simulations and showing that we underestimate the magnitude of
the heavy-flavor contribution to the isolated lepton yields. We also show that
the isolation requirement acts as a narrow bandpass filter on the momentum of
the isolated lepton, and we illustrate the effect of this filter on the
background to Higgs boson observation in the dilepton mode. We introduce and
justify a new rule of thumb: isolated electrons and muons from heavy flavor
decay are produced with roughly the same distributions as b and c quarks, but
with 1/200 times the rates of b and c production, respectively.
