Make simple histograms

Prerequisites and goal

Complete the tutorial setup and build tea. The goal is to histogram the muon multiplicity, transverse momentum, and pseudorapidity for a semileptonic top background sample.

Prepare the configuration

From the analysis root:

cp tea/configs/das_exercises/task1_simple_histograms.py configs/simple_histograms.py

Set the paths and histogram definitions:

base_path = "/eos/cms/store/group/committee_schools/2025-cmsdas-hamburg/llp/samples"
process = "background_ttsemileptonic"

inputFilePath = f"{base_path}/{process}/output_0.root"
histogramsOutputFilePath = f"../results/tutorial/histograms/{process}.root"

defaultHistParams = (
  ("Event", "nMuon", 50, 0, 50, ""),
  ("Muon", "pt", 400, 0, 200, ""),
  ("Muon", "eta", 100, -2.5, 2.5, ""),
)

weightsBranchName = "genWeight"

Build and run

Rebuild so the new config is linked into bin/, then run:

source tea/build.sh
cd bin
./histogrammer --config simple_histograms.py

Expected output

results/tutorial/histograms/background_ttsemileptonic.root should contain Event_nMuon, Muon_pt, Muon_eta, and cut-flow histograms. Inspect the keys with:

rootls ../results/tutorial/histograms/background_ttsemileptonic.root

If the file is missing, check the input path and output directories.

Next step

Plot the histograms and overlay an LLP signal.