Correlations with Invariant Mass

Data Set1: STAR 2008 pp data

   - I used the following query conditions in the file_catalog for this study: 

        trgsetupname=ppProduction2008,production=P08ie,filetype=daq_reco_MuDst,filename~st_physics,tpc=1,sanity=1

Trigger: etot-mb-l2

Trigger Simulator: L2Gamma from 2006

The analysis was done using the same algorithm and cuts used in Weihong He's final analysis of the Run 6 data.

Data Set 2: STAR 2006 pp data

    - I used a subsample of Weihong's final pi0 trees to make the same correlation plots for the 2006 data.

Summary:

In my previous posts there has been some discrepancy in the width of the mass peak for the pions between run 6 and run 8 data.  In order to understand this better, I made some correlation plots as well as 1-D distributions of some of the contributing factors.  Hopefully we can see something from these.  The plots are divided into 2 pT bins with ~half of the statistics in each for the 2008 data.

Figure 1:  EEMC Detector Eta vs. Mass

Figure 2: Physical Eta vs. Mass

Figure 3: Zgg vs. Mass

Figure 4: Phigg vs. Mass (note different y scales)

Figure 5:  Z vertex vs. Mass

From here on the entire run 6 data set is used for comparison and the run 8 data is normalized to the run 6 samples.

Figure 6: Zgg Distribution ( Run6 all pT => black : Run8 all pT => blue: Run8 pT < 6.5 => red: Run8 pT >6.5 => green : Run 6 pT < 6.5 => yellow: Run6 pT > 6.5 => magenta)

Figure 7: Point Et Distribution ( Run6 => black : Run8 => red ) 

run 6 points = 14675345 and run 8 points = 14571573

 Figure 8: Pion Energy Distribution ( Run6 => black : Run8 => red : Run8 with L2 Gamma => green)

run 6 pions = 853595 and run 8 pions = 98457

 Figure 9: Pion Pt Distribution ( Run6 => black : Run8 => red : Run8 with L2 Gamma => green)

run 6 pions = 853595 and run 8 pions = 98457