  Sufficiently energetic collisions of heavy ions result in the formation of a
droplet of a strongly coupled liquid state of QCD matter known as quark-gluon
plasma. By using gauge-gravity duality (holography), a model of a rapidly
hydrodynamizing and thermalizing process like this can be constructed by
colliding sheets of energy density moving at the speed of light and tracking
the subsequent evolution. In this work, we consider the dual gravitational
description of such collisions in the most general bulk theory with a
four-derivative gravitational action containing a dynamical metric and a gauge
field in five dimensions. Introducing the bulk gauge field enables the analysis
of collisions of sheets which carry nonzero "baryon" number density in addition
to energy density. Introducing the four-derivative terms enables consideration
of such collisions in a gauge theory with finite gauge coupling, working
perturbatively in the inverse coupling. While the dynamics of energy and
momentum in the presence of perturbative inverse-coupling corrections has been
analyzed previously, here we are able to determine the effect of such finite
coupling corrections on the dynamics of the density of a conserved global
charge, which we take as a model for the dynamics of nonzero baryon number
density. In accordance with expectations, as the coupling is reduced we observe
that after the collisions less baryon density ends up stopped at mid-rapidity
and more of it ends up moving near the lightcone.
