  The QCD critical point can be found in heavy ion collision experiments via
the non-monotonic behavior of many fluctuation observables as a function of the
collision energy. The event-by-event fluctuations of various particle
multiplicities are enhanced in those collisions that freeze out near the
critical point. Higher, non-Gaussian, moments of the event-by-event
distributions of such observables are particularly sensitive to critical
fluctuations, since their magnitude depends on the critical correlation length
to a high power. We present quantitative estimates of the contribution of
critical fluctuations to the third and fourth moments of the pion and proton,
as well as estimates of various measures of pion-proton correlations, all as a
function of the same five non-universal parameters. We show how to use
nontrivial but parameter independent ratios among these more than a dozen
fluctuation observables to discover the critical point. We also construct
ratios that, if the critical point is found, can be used to overconstrain the
values of the non-universal parameters.
