I took a look at the h-/h+ ratio for the 2012 data using code I got from Grant Webb, who had done this for previous years.

Data was from P12id. 

Data is in /star/institutions/ucla/klandry/QAnalysis/2012/pp200/HmHp/

I plotted the h-/h+ ratio vs track Pt for 5 different situations. These were using:
1) Data from a single run early in 2012 (run number 13068034)
2) Data from a single run late in 2012 (run number 13072010)
3) Data from the first 40 runs in 2012
4) Data from the last 40 runs in 2012
5) Data from all of 2012 combined

This was done to find any discrepancies between different times during 2012.

1) A single run early in 2012 (run number 13068034)

2) A single run late in 2012 (run number 13072010)

 

3) The first 40 runs in 2012

4) The last 40 runs in 2012

5) All of 2012


 

This figure is closer look at the above plot in the Pt region between 0 and 3 GeV.

In all the plots, there is a significant decrease of the h-/h+ ratio starting around Pt = 3 GeV.
The west and east sections behave the same.

I also plotted the h-/h+ ratio vs "run number" for all the runs in 2012.
The ratio for each run was found by fitting that run's h-/h+ VS Pt graph with a constant. I did this two ways. First by fitting the entire range, and then fitting just between 0 and 3 GeV. Pt of 3 GeV was chosen because in the plot of h-/h+ vs Pt, 3 GeV is where the ratio noticeably starts to decrease.

There is a slight increase in h-/h+ in both the west and east sections of the TPC from .95 to about .957. We haven't found an explanation of this.

 List of Runs:
13067013
13067014
13067015
13067017
13068017
13068022
13068027
13068029
13068034
13068036
13068037
13068057
13068058
13068059
13068060
13068084
13068085
13068086
13068087
13068088
13068090
13069001
13069002
13069003
13069004
13069005
13069006
13069007
13069008
13069009
13069013
13069014
13069016
13069017
13069018
13069020
13069021
13069022
13069023
13069024
13069026
13069027
13069029
13069030
13069031
13069035
13069036
13069066
13069067
13069068
13069069
13069073
13070006
13070008
13070010
13070011
13070012
13070014
13070015
13070016
13070017
13070018
13070019
13070020
13070021
13070022
13070024
13070025
13070026
13070027
13070030
13070056
13070057
13070058
13070059
13070060
13070061
13071003
13071004
13071005
13071006
13071008
13071009
13071010
13071011
13071012
13071028
13071029
13071031
13071032
13071033
13071034
13071037
13071038
13071040
13071041
13071042
13071043
13071045
13071046
13071048
13071050
13071051
13071055
13071064
13072001
13072002
13072015
13072003
13072004
13072005
13072006
13072007
13072008
13072009
13072010
13072011
13072014
13072016
13072017
13072018
13072019
13072020