Previously, I had determined the relevant tracks to consider for calculating the tracking efficiency:

https://drupal.star.bnl.gov/STAR/blog/dmawxc/update-03072018-run-9-pp-efficiency-adjusting-dca-idvxend-and-pid-selection

However, I made a few silly mistakes when I was doing the calculation.  First, I was selecting pions by requiring that the track ID (not particle ID) be 7 or 8.  And second, I forgot that the PID's for pi+ and pi- are 8 and 9 respectively (not 7 and 8).  After fixing these mistakes, the pion tracking efficiency for the pTparton = (9, 11) GeV/c bin comes out to be:

And the tracking efficiency for all charged hadrons in the bin pTparton = (9, 11) GeV/c comes out to be:

With these issues resolved, I went ahead and calculated the tracking efficiency using all bins of partonic pT:

As you can, see the fit has the wrong functional form, so please ignore those functional parameters.