Critical viscosity exponent for a classical fluid

The dynamic renormalization group yields a value for the critical exponent which we find to be too large. We believe that the true value is close to the decoupled mode value of $\frac{8}{15}{\pi }^2=0.054\mathrm{}$. The error in the renormalization-group calculation comes from the two-term truncation of the $\epsilon$ expansion. The ${\epsilon }^3$ term that is neglected is of opposite sign and as large as the ${\epsilon }^2$ term that is included. By avoiding the $\epsilon$ expansion entirely, we eliminate any truncation error and achieve greatly improved accuracy.