This program runs RooFit on a TTree. The user can define cuts, observables and pdfs for their analysis with a fhicl file.
To download a version:
To setup (on a mu2egpvm machine):
setup mu2e
source setup.sh
If not working on a mu2egpvm machine, you will need to be able to see Mu2e Offline releases on cvmfs and do your equivalent of "setup mu2e"
To compile:
scons -j4
roofitter does not need to run on TrkAna trees, but we will use one for this example:
mu2e -c $MU2E_BASE_RELEASE/TrkDiag/fcl/TrkAnaRecoEnsemble-Data.fcl -s ensemble-file.art --TFileName trkana.root
To fit the momentum spectrum we can use this example:
roofitter -c Main/fcl/example.fcl -i trkana-file.root -t TrkAnaNeg/trkana -o ana.root
And you can plot the result:
root -l Main/scripts/plot_cemDio_mom.C("ana.root")
If you open up example.fcl, you will see that we #include two files specific to TrkAna:
obs_leaves_trkana.fcl -- defines the leaves for the observables cuts_cd3_trkana.fcl -- defines the leaves for the cut variables
The analysis itself is defined in ana_cemDio_mom.fcl. It is worth noting that in a single run of roofitter, you can run more than one analysis by adding to the line:
analyses : [ @local::cemDio_mom ]
in example.fcl.
If you look in ana_cemDio_mom.fcl, you will see that we #include files to define the observable and components of this analysis.
- the observable file defines histogram limits, and possible efficiency and resolution functions for the variable
- the component file defines possible truth PDFs for the component for a given observable
Back in the ana_cemDIO_mom.fcl file, we define the observables ("mom") and components ("cemLL" and "dioPol58") that we want as well as the cuts ("AllCD3Cuts").
Finally, we define the full model that we want to fit. Note that the PDF names for each component are:
- true PDF name + observable + "EffResp"
where "EffResp" is if you want the efficiency and resolution effects included.
-c, --config [cfg file]: input configuration file
-i, --input [root file]: input ROOT file containing the tree (overrides anything in cfg file)
-t, --tree [tree name]: tree name (inc. directory) in the input file (overrides anything in cfg file)
-o, --output [root file]: output ROOT file that will be created (overrides anything in cfg file)
-d, --debug-config [filename]: print out the final config file to file
-h, --help: print this help message