I took a look at recent sDCA distributions for good tracks (used in the SpaceCharge calibrations) vs. phi. I used the SpaceCharge calibration histogram files from Alán, which may not be the final calibration, so there may be some offset from zero. What's more interesting is the observable systematics in phi. Run 12 pp510 shows some particularly unusual behavior near two regions with dead TPC channels: sectors 12 and 1 on the west (phi from 4.5-5.5), and sector 20 on the east (phi from 5.5-6.0) as well as the two sectors next to it.

Here is what I executed: 

root -l /star/institutions/uta/alandav/TemporalSC_GL2012pp500RFF/hists2.734_9.55/Hist*.root
.x ~/str/CODES/MISC/plotDcaPhi.C("Run12_pp510")
...
root -l /star/institutions/uta/alandav/TemporalSC_GL2012UU193RFF/hists4.256_7.25/Hist*root
.x ~/str/CODES/MISC/plotDcaPhi.C("Run12_UU193")

And here are the plots...

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-Gene