Measuring GlueX proton-track reconstruction efficiencies using missing-proton events

The analysis is based on PART files that are generated by the ReactionEfficiency plugin in halld_recon (needs at least commit 257a47e; see also PR #739). Scripts to run the plugin reside in launchPlugin.

The PART files are further processed by DSelector_<channel>.{h,C} selectors, which are run over the data by runSelector.py. Currently, the produced custom flat ROOT trees need to be further processed by makeBruFitTree.py, which produces .root.brufit files. These files contain the trees from which missing-mass squared distributions are generated. The proton peak in these distributions is fit using histogram-based shapes for signal and background that are extracted from bggen Monte Carlo. runFits.py is the master script that performs these fits and produces .pdf files with the result plots.

The fits are based on the BruFit package, which bins the data and performs the fits in the kinematic bins using RooFit. Currently, the boot branch and ROOT version 6.28 or higher are needed to run the fits.

Workflow

1. Run the ReactionEfficiency plugin over *.hddm files of a particular data sample using the official launch.py script; instructions are provided in the job_*.config files.
2. Copy/link the tree_<reaction>_Effic_<run number>.root files produced by the the ReactionEfficiency plugin into the corresponding subdir in data.
3. Edit FitConfig values in fitMissingMassSquared.py and variables in runSelector.py.
4. Run runSelector.py to create flat-tree files, histogram files, and Brufit-tree files.
5. Edit and run runFits.py to perform fits and extract efficiency values.