  Theoretical arguments, supported by other indirect evidence, suggest that the
wave function of high-x partons should be narrower than that of low-x ones. In
this article, we present a modification to the variable impact parameter
framework of Pythia 8 to model this effect. In particular, a Gaussian hadronic
matter profile is introduced, with a width dependent on the x value of the
constituent being probed. Results are compared against the default single- and
double-Gaussian profiles, as well as an intermediate overlap function.
