This page is documentary purpose.

 Motivation:

FTPC charge identification ability is important in d+Au ridge study. 

Signed dca :Signed radial component of global DCA (projected) should be symmetric ideally. 

Here signed dca is invested for BField and Charge combinations in several η windows in TPC and FTPC.

Method:

Signed dca distirbutions (global)

Data set:

Run3

|Vz| < 50 cm
global track in TPC and FTPC
nHitsFit > 25 points for TPC, nHitsFit > 5 points for FTPC
nHitsFit/nHitsPoss >= 51%
globa dca < 3 cm
|eta|<1 for TPC

Results:

	0.15<pT<0.5	0.5<pT<1	1<pT<3
-3.8<η<-3.3
-3.8<η<-2.8
-1<η<-0.6
-0.6<η<-0.3
-0.3<η<0
0<η<0.3
0.3<η<0.6
0.6<η<1
2.8<η<3.3
3.3<η<3.8

Conclusion:






FTPC-Au: 
   Positive charge are not symmetric and flip with BField.
   Negative charge are symmetric

TPC:
   Both positive and negative are not symmetric. They bias towards the same side and flip with BField.

FTPC-d:
   All not symmetric. RF negative and FF positive tend to bias towards the same side. So do RF positive and FF negative.