Glossary

Framework and CMS-computing vocabulary, in plain terms. For the quick on-ramp version see Key terms.

anaTuple

The analysis-level ntuple FLAF produces from NanoAOD — a slimmed, skimmed ROOT tree with the objects, weights and flags an analysis needs. Produced by AnaTupleFileTask, merged by AnaTupleMergeTask.

AnaProd

The part of FLAF (AnaProd/) that produces anaTuples from NanoAOD, including anaTupleProducer.py (run in the FLAF environment, or inside CMSSW when the analysis sets use_cmssw_env_AnaTupleProduction, as HH→bb̄ττ does).

Branch

One independent work unit of a workflow task. What it represents depends on the task — an input file, a dataset, or a variable. Select with --branches; over several eras a branch is numbered era id × 1 000 000 + its number in the era's own map (see Eras).

Bundle

A tarball of code/environment shipped to a batch worker so a job can run without the shared AFS area. See HTCondor.

Combine

The CMS statistical tool (HiggsAnalysis/CombinedLimit) used for limits and fits. FLAF builds v11.1.0 in the CMSSW area and standalone against the ROOT of flaf_env (see The environment).

Corrections

The shared submodule providing object corrections and systematic variations (pileup, b-tag, triggers, …). The analysis configuration (corrections: in global.yaml, optionally per dataset or process) gives each correction the stage(s) where it is applied: AnaTuple (anaTuple production), AnaTupleMerge, AnalysisCache or HistTuple (e.g. HH→bb̄ττ applies its τ-ID, muon, electron and trigger scale factors at HistTuple). A Corrections object is built per dataset, era and stage and handed to the analysis hooks as corrections= (see Architecture).

CMSSW

The CMS software framework, installed by env.sh under soft/. Pipeline steps that need it (e.g. HH→bb̄ττ's anaTuple production, datacard creation and Combine, some payload producers) are run inside it by the tasks themselves; for interactive commands env.sh defines the cmsEnv alias.

CRAB

The CMS service that submits jobs to WLCG sites. FLAF submits workflow branches to it with --workflow crab. See Running on CRAB.

CVMFS

The CERN read-only software-distribution filesystem (/cvmfs/…) from which FLAF gets compilers, Python, ROOT (LCG stacks), CMSSW and the POG correction files (/cvmfs/cms-griddata.cern.ch).

DAS

The CMS Data Aggregation System — the catalogue of official datasets and the source of the dataset name convention (/A/B/TIER). File lists and disk locations are resolved via Rucio (see below); DAS is queried only for per-file event counts, which feed the job-cost estimate and are optional.

Dataset

One CMS sample (a simulated process or a chunk of data), declared under a short name (e.g. TTto2L2Nu) in datasets.yaml, with its DAS name per NanoAOD version in nanoAOD:. See Datasets.

Era

A CMS data-taking period (Run3_2022, Run3_2023BPix, …), passed as --era (one era, or several separated by commas for one run over all of them). Selects datasets, corrections and the NanoAOD version. See Eras.

Filesystem (fs_*)

A named storage location (local, EOS or a WLCG site) where a given output type is read/written. Configured in user_custom.yaml. See Storage.

FLAF

The Flexible LAW-based Analysis Framework — the shared machinery (tasks, config, environment, CI) included as a submodule in each analysis.

histTuple

An ntuple, derived from anaTuples, that carries the computed analysis observables, ready to be histogrammed. Produced by HistTupleProducerTask.

HTCondor

CERN's batch system. FLAF submits workflow branches to it with --workflow htcondor. See HTCondor.

LAW

Luigi Analysis Workflow — the layer over Luigi that gives FLAF its command-line interface, remote-storage handling and batch submission.

Luigi

The Python workflow engine that tracks task dependencies and outputs underneath LAW.

Meta-process

A process template that expands into a family of concrete processes (e.g. all resonant mass points). Marked is_meta_process: true. See Processes & models.

NanoAOD

The compact CMS data format that is the input to the whole pipeline.

Payload producer

A configured component (under payload_producers in global.yaml) that computes analysis observables such as DNN scores or a mass reconstruction. Each producer runs in its own AnalysisCacheTask (--producer-to-run <name>), one branch per merged anaTuple file; HistTupleProducerTask then reads the cached columns, named <producer>_<column>. All three analyses define payload producers.

Physics model

The named set of processes (background/signal/data) an analysis uses. TestModel is the small testing set; production uses the full model. Defined in phys_models.yaml.

PlotKit

FLAF's plotting toolkit (a submodule of FLAF, cms-flaf/PlotKit). Renders the stacked CMS plots with matplotlib + mplhep by default (no ROOT required) and can optionally render through ROOT + cmsstyle. It reads the analysis config/plot/*.yaml files and can also run standalone (python -m PlotKit.cli).

Process

A physics object built from one or more datasets (e.g. "TT", "DY", "signal") — what you plot and fit. Defined in processes.yaml.

Proxy (VOMS)

A short-lived credential derived from your grid certificate that authorises grid/EOS access. Created with voms-proxy-init. FLAF uses the file X509_USER_PROXY points to; env.sh sets that variable to data/voms.proxy only when it is not already set.

Rucio

The CMS data-management service. For a dataset read by its DAS name (a NanoAOD version other than HLepRare), InputFileTask queries it for the list of NanoAOD files and their disk locations; skims listed from a storage directory (fs_nanoAOD) do not use it. See Storage.

RunKit

Workflow utilities vendored into FLAF as a regular directory (formerly a submodule). Imported as FLAF.RunKit.<module>.

StatInference

The shared submodule for datacard creation and limit/fit tooling (used by the HH analyses).

Task

One stage of the pipeline with defined inputs, outputs and a run step. The unit LAW schedules. See Tasks & LAW and the Task reference.

Version

The --version label that namespaces a run's outputs so productions and tests don't collide.

WLCG

The Worldwide LHC Computing Grid — the federation of sites (T1_*, T2_*, T3_*) where CMS data and FLAF outputs are stored.

Workflow

A task that splits into many branches, runnable local, on htcondor or on crab.