Codes for Z+b analysis

General descriptions

The codes are based on ROOT TSelector. They include a reader (Reader class), processor (Processor class derived from Reader), abstracted selector (Selector class) and one or more selections (ZbSelection for example). Analyzers can add a selection to do a specific analysis. All selections are added to the processor to analyze the events. Note that all selections are independent. Therefore, multiple analyses can be performed independently on the same events.

The cuts used in selections are defined in Configs/inputParameters. Users can provide different cut file at command line. These cut values are read into the global variable CUTS, which is an instance of Parameters, defined in src/Global.h. The histograms can be grouped in src/Plots.cxx and initalized in SlaveBegin of the selection. They can also included directly as a member of the selection class.

For convenience, the physics objects, leptons and jets for example, are wrapped by objects in src/Obj.cxx. They contain a TLorentzVector together with other variables (for example isolation for lepton and deepCSV for jet). All corrections are implemented in these object classes.

To build the code type "make". Use "make name_of_class.o" to compile a specific class. To clean: "make clean". The easiest way to compile the code is to execute the "make" inside CMSSW environment (after eval scramv1 runtime -csh).

The workflow starts from executing the command line

./main -filelist fileList.txt -cfg Configs/inputParameters.txt -data 0 -out out.root -syst none -firstentry 0 -lastentry 10000

fileList.txt: list of data files -cfg: file with input parameters (cuts for example) -data 0: this is MC (set 1 for data) out.root: output data name -syst none: do not valuate systematics. -firstentry 0 -lastentry 10000: loop from entry 0 to 10000. These setting are for testing purpose. All events are processed by default.

Code contents

Main program: Ana.cxx

StdArg.hpp: command line parser

Configs: configuration for example cuts

src: codes

1. Global.h Global.cxx: global constants and variables. They contain Parameters class to read parameters (cuts for example) from configuration
2. Reader.h Reader.cxx: derived class from TSelector to handle ROOT tree (chain) reading. It is created automatically by MakeSelector
3. Processor.h Processor.cxx: derived class from "Reader" to handle processing of events
4. Selector.h Selector.cxx: base class for all selections
5. ZbSelection.h ZbSelection.cxx: a selection to select Z+b-jet events
6. SelectionTemplate.h SelectionTemplate.cxx: templates for creating a selection

Howto

1. Define a new cut: Add it to the Configs/inputParameters.txt. In Parameters class: add the name to the constructor of Parameters, add a private variable, define how to get and set it in "Get" and "Set"
2. To make histograms: Define a class for a group of them in src/Plots.cxx or define them as members of the selection class. Book them and add them to the list of output in SlaveBegin of the selection class Fill them in Process of the selection class Finally, save them in SlaveTerminate of the Processor class
3. To save a cut values used in a selection to the output root file: Add the value to TParameter and append this TParameter to a list in Terminate of selection class