  We show that measurements of the rapidity dependence of transverse momentum
correlations can be used to determine the characteristic time $\tau_\pi$ that
dictates the rate of isotropization of the stress energy tensor, as well as the
shear viscosity $\nu = \eta/sT$. We formulate methods for computing these
correlations using second order dissipative hydrodynamics with noise. Current
data are consistent with $\tau_\pi/\nu \sim 10$, but targeted measurements can
improve this precision.
