FCCee_HiggLFV

How to run

root -l -b -q 'analyze_pipeline.cpp("PATH_TO_ROOT_FILE_OR_PATTERN","OUTPUT_ROOT_FILE","CONFIG_JSON_FILE")'

• PATH_TO_ROOT_FILE_OR_PATTERN: e.g. samples/HMuTauE_LFV_125.root or samples/ (to process all ROOT files in the directory)
• OUTPUT_ROOT_FILE: e.g. out_hist_cfg.root contains the histograms after applying the pipeline selections
• CONFIG_JSON_FILE: e.g. pipeline.json defines the selection pipeline and parameters

How to add new selections

1. Implement the new selection class in selections.cpp (e.g. HToMuTauESelection), following the structure of existing selections.
2. Add the new selection class declaration in selection.h.
3. In pipeline_config.cpp, add a case in the selection factory function to create an instance of your new selection class when the corresponding name is encountered in the config.
4. In pipeline.json, add a new entry in the "selections" list with the name that matches the case you added in pipeline_config.cpp and specify any parameters needed for that selection.

How to add new parameters

1. Define the new parameter in type.h (e.g. double my_new_param;) under the Parameters struct.
2. In pipeline_config.cpp, update the code that reads the config file to parse the new parameter and store it in the Parameters struct.
3. In pipeline.json, add the new parameter under the "parameters" section with an appropriate value.
4. (Optional) Add print statements in analyze_pipeline.cpp to verify that the new parameter is being read correctly during execution.

Metadata

The Meta struct is used to store intermediate information about the event that can be accessed by different selections in the pipeline. For example, it can store the indices of the selected leptons, the flavor of the Z boson leptons, and any kinematic variables that are calculated during the selections.

How to use Meta

1. Define new variables in the Meta struct in type.h (e.g. double deltaR_mu_e;).
2. In your selection class (e.g. HToMuTauESelection), calculate the desired variable and store it in the Meta struct (e.g. meta.deltaR_mu_e = deltaR_mu_e;).
3. In subsequent selections in the pipeline, you can access this variable from the Meta struct (e.g. double deltaR = meta.deltaR_mu_e;).