This page is documentary purpose.

 Motivation:

Follow the d+Au Ridge - FTPC charge identification discussion, www.star.bnl.gov/protected/bulkcorr/yili/dAuRidge/1stGPC.html

If there may artificial effect in FTPC Primary tracks leading to the ftpc positive and negative difference, it may also have similar influence on BField. But BField dependence is not observed in primary tracks. See drupal.star.bnl.gov/STAR/blog/yili/dau-ridge-bfield-dependence.

Here we investigate BField dependence on global tracks for dihadron correlations with different associate particle charges.
 

Method:

1. Global track positive and negative distribution ratio in FTPC

2. TPC-FTPC dihadron correlation with ZDC centrality ReservedFullField vs FullField. 

Data set:

Run3

|Vz| < 50 cm
global track for both TPC and FTPC
nHitsFit > 25 points for TPC, 5 points for FTPC
nHitsFit/nHitsPoss >= 51%
globa dca < 3 cm
|eta|<1 for TPC, 2.8<|eta|<3.8 for FTPC

Results:

FF	RF