Tree files are produced under /psn0777/Mudst directory. Following this description, the warning from StTriggerStudyMaker during the cons process was suppressed in this code QA task.
The cons command successfully ran and its log can be found here.
Because all the MuDsts used in the original analysis may not be available at this time due to file relocation, PAs and GPC selected the following two MuDst from Run15 p+p 200 GeV data set for the reproducibility check of tree files.
root://xrdstar.rcf.bnl.gov:1095//home/starlib/home/starreco/reco/production_pp200trans_2015/ReversedFullField/P15ik/2015/089/16089005/st_fms_16089005_raw_5000001.MuDst.root

root://xrdstar.rcf.bnl.gov:1095//home/starlib/home/starreco/reco/production_pp200trans_2015/ReversedFullField/P15ik/2015/089/16089005/st_fms_16089005_raw_5000016.MuDst.root

Tree files generated by PA can be found here:

/star/u/xchu/work/Run15/DiHadronCorr/Ana/ForMudstTest/jobs/output/35B4C034960F09FA01BD4C6CA36B5B00_0.local.tree.root

/star/u/xchu/work/Run15/DiHadronCorr/Ana/ForMudstTest/jobs/output/35B4C034960F09FA01BD4C6CA36B5B00_1.local.tree.root

Tree files generated by GPC can be found here:
/star/u/tdrk/GPC/324/psn0777/Mudst/jobs/22F26F2D3C1233A09A3A3C10A8993A49_0.local.tree.root

/star/u/tdrk/GPC/324/psn0777/Mudst/jobs/22F26F2D3C1233A09A3A3C10A8993A49_1.local.tree.root

Confirmed tree files from both sides are identical. See printouts of these root files (PA0, PA1, GPC0, GPC1).

 2: Analysis of tree files
Tree analyses were done using codes in /psn0777/Cal/<system> (<system>=pp, pAu1, pAu2, pAl).
As was done for the cons in the tree production, the warning from StTriggerStudyMaker was suppressed in this study.
The cons command successfully ran and its logs can be found in the attachments (pp, pAu1, pAu2, pAl).
From this point forward, this code QA work uses tree files generated by PA for their original analysis. See <system>.tree.list files in each CVS area for the complete list.

All jobs submitted to the condor system successfully finished without any issue. All output root files that contain histograms could be merged according to the procedure in the README files.

 3: Analysis of histograms
Histograms analyses were done in /psn0777/Draw. The analysis macro of dipi0.C runs without problem with 4 different sets of entities specified in the README file.
Its outputs are identical to the last digits with those from PA's original analysis stored in /star/u/xchu/pwg/DiPion0Corr/Ana/Draw/txt
 4: Plotting paper figures
Paper figures are also prepared in /psn0777/Draw. Macros f1(2,3,4).C run well.

The latest physics plots (as of 2021 Aug. 28) were successfully reproduced. See the attached figures.