Update README.md

README.md

@@ -7,23 +7,31 @@ python3 -m pip install coffea --user
 ```
 All coffea documentation is hosted at https://coffeateam.github.io/coffea/
 ## Getting Started
-Begin by cloning the repository:
+Begin by cloning the repository,
 ```
 git clone git@github.com:UMN-CMS/WrCoffea.git
 cd WrCoffea
 ```
 ## Running the analyzer
 ### Example
-The command below will locally analyze one DY nanoAOD root file and one $t\bar{t}$  file from the 2018 UL MC samples:
+The command below will locally analyze one root file from each of the 2018 UL background MC samples:
 ```
-python3 run_analysis.py UL18_bkg --output_hists example_hists.root  --max_files 1
+python3 run_analysis.py UL18_bkg allMC --hists example_hists.root --masses example_masses.root  --max_files 1
 ```
-The output is a root file (`example_hists.root`) containing histograms of kinematic variables, across all basic analysis regions. 
+Two files are outputted: a root file containing histograms of kinematic variables across all basic analysis regions (`example_hists.root`), and a root file with branches of the 3-object invariant mass ($m_{ljj}$) and 4-object invariant mass ($m_{lljj}$) (`example_masses.root`).
 
 ### Arguments
-To run the analyzer, a sample set must be given as an argument. Currently, only `UL18_bkg` has been created, but there are also plans to include `UL18_signal` and `UL18_data` sample sets, as well as the rest of Run II (2016 and 2017). 
+To run the analyzer, a sample set and process must be specified as arguments:
 
-There is an additional optional flag `--output_masses` that outputs a root file with branches of the 3-object invariant mass ($m_{ljj}$) and 4-object invariant mass ($m_{lljj}$). To analyze over all files in each dataset, simply omit the `--max_files` flag. To run the analyzer without computing any output files, omit both `--output_hists` and `--output_masses`.
+ - Sample sets: Currently, only `UL18_bkg` has been created, but there are also plans to include `UL18_signal` and `UL18_data` sample sets, as well as the rest of Run II (2016 and 2017).
+ - Process: The MC process to be analyzed. Options for individual processes are `DYJets`, `tt+tW`, `WJets`, `Diboson`, `Triboson`, `ttX`, `SingleTop`, or to analyze the entire sample set, use `allMC`.
+
+To analyze over all files for the given process, simply omit the `--max_files` flag. To run the analyzer without computing any output files (perhaps for debugging purposes), omit both `--output_hists` and `--output_masses`.
+
+For more information, enter:
+```
+python3 run_analysis.py --help
+```
 
 ## Future Work
 In the near future there are plans to scale out the framework to use distributed computing resources needed to analyze all 2018 UL MC samples and files.