  The latest CTEQ6.6 parton distributions, obtained by global analysis of hard
scattering data in the framework of general-mass perturbative QCD, are employed
to study theoretical predictions and their uncertainties for significant
processes at the Fermilab Tevatron and CERN Large Hadron Collider. The
previously observed increase in predicted cross sections for the
standard-candle W and Z boson production processes in the general-mass scheme
(compared to those in the zero-mass scheme) is further investigated and
quantified. A novel method to constrain PDF uncertainties in LHC observables,
by effectively exploiting PDF-induced correlations with benchmark standard
model cross sections, is presented. Using this method, we show that the
top-antitop pair cross section can potentially serve as a standard candle
observable for the LHC processes dominated by initial-state gluon scattering.
Among other benefits, precise measurements of $t\bar{t}$ cross sections would
reduce PDF uncertainties in predictions for single-top quark and Higgs boson
production in the standard model and minimal supersymmetric standard model.
