We are continuing to try to figure out if the tracking resolution in the Run 9 dijet embedding sample is as expected.  My previous attempts to calculate the resolution seemed to be wrong, so we gave another method a shot.  Now we're trying to recreate the plot on page 12 of this presentation by Kolja:

https://drupal.star.bnl.gov/STAR/system/files/2017-05-24%20momentum_resolution.pdf

So how I went about doing this is I'd plot the matched 'pTreco' distribution for a "fixed" (within some bin) 'pTmc'.  Then I'd fit the resulting 'pTreco' distribution with a gaussian, and the RMS of that fit I assume to be the tracking efficiency for the given 'pTmc'.  Here's what I got for 'pTmc' = [5, 5.2] GeV/c:

And now, here's the calculated values of sigma as a function of average 'pTreco' (the 'pTmc' bin size was 2 GeV/c):

Where the average 'pTreco' is the mean of the gaussian fit.  And here's the same calculation using a substantially smaller bin size (0.2 GeV/c in 'pTmc') and using the "average" 'pTmc' (meaning the bin center) in the x-axis:

I also checked another method: I made a plot of 'pTmc - pTreco' vs. 'pTmc', then I fit each slice in 'pTmc' (the size of each slice was 0.1 GeV/c) with a guassian, and plotted the calculated RMS values vs. 'pTmc'.  This produces a very similar result:

Edit [05.06.2018]: previously, this post stated that our distributions had the opposite curvature of Kolja's.  However, I had forgot to put the y-axes of our distributions in a log-scale when I made that assessment.  The corrected plots can be found in the link below (plotted alongside Kolja's distribution).  With the proper axes, the distributions look very similar as expected.
https://drupal.star.bnl.gov/STAR/blog/dmawxc/05062018-run-9-pp-resolution-study-another-method-log-scales