  Dijet acoplanarity is dominated by vacuum (Sudakov) pQCD radiation even in
Pb+Pb collisions, but future higher precision measurements of the tails of the
acoplanarity distributions can help to resolve {\em separately} the medium
opacity, $\chi=L/\lambda$, and the color screening scale $\mu^2$ from the path
averaged BDMS saturation scale $Q_s^2[\chi,\mu]=\int dL\;
\hat{q}(E,T(L))\propto \mu^2 L/\lambda $, that is already well constrained by
nuclear modification factor data on $R_{AA}(p_T)$. We compare Gaussian (BDMS)
and non-Gaussian (GLV) models of medium broadening of vacuum (Sudakov) induced
acoplanarity distributions in A+A. With few percent accuracy on the ratio of
A+A to p+p distributions, experiments can easily identify non-Gaussian Landau
and Rutherford tails due to multiple collisions. However, we find that
sub-percent precision will be required to constrain $\chi$ and $\mu$ separately
from $Q_s$.
