The collaboration has concerns about the SMD, and not without reason.  They, they SMDs, have been notoriously hard to understand and model.  And the SMD is central to my analysis so I need to be able to trust that I understand it.  To this end, I am using a comparison of Zgg in Data and MC to claim that I understand the SMDs well enough.  The SMDs are mainly used in my analysis to split the energy of tower clusters into single photons.  Zgg is a measurement of this splitting.  This effect is exaggerated at higher values of Pt, where the two photons from a single pion are most likely to fall in a single pion.

Below is nine plots of Data (black) Vs MC (red) for my 9 pt bins in my cross section analysis.  The MC is normalized (over all pt bins) to the integral of the data.

As you can see, the data and MC line up very well within statistics.  The last bin should be taken with multiple grains of salt considering the number of entries in the hists.  This is the justification I offer for using simulated SMD response in calculating correction factors and background shapes to compare to the data.