Transits of the QCD critical point

We analyze the evolution of hydrodynamic fluctuations in a heavy-ion collision as the system passes close to the QCD critical point. We introduce two small dimensionless parameters lambda and Delta(s) to characterize the evolution. lambda compares the microscopic relaxation time (away from the critical point) to the expansion rate lambda (math) tau(0)/tau(Q), and Delta(s) compares the baryon to entropy ratio, n/s, to its critical value, Delta(s) (math) (n/s - n(c)/S-c) / (n(c)/S-c). We determine how the evolution of critical hydrodynamic fluctuations depends parametrically on lambda and Delta(s). Finally, we use this parametric reasoning to estimate the critical fluctuations and correlation length for a heavy-ion collision and to give guidance to the experimental search for the QCD critical point.