EDM4hep I.

EDM4hep II.

#-------------  CalorimeterHit
edm4hep::CalorimeterHit:
  Description: "Calorimeter hit"
  Author: "EDM4hep authors"
  Members:
    - uint64_t cellID  // detector specific (geometrical) cell id
    - float energy [GeV]              // energy of the hit
    - float energyError [GeV]         // error of the hit energy
    - float time [ns]                // time of the hit
    - edm4hep::Vector3f position [mm] // position of the hit in world coordinates
    - int32_t type                   // type of hit
            

EDM4hep 1.0

edm4hep::TrackerHit:
  Description: "Tracker hit interface class"
  Author: "Thomas Madlener, DESY"
  Members:
    - uint64_t cellID // ID of the sensor that created this hit
    - int32_t type // type of the raw data hit
    - int32_t quality // quality bit flag of the hit
    - float time [ns] // time of the hit
    - float eDep [GeV] // energy deposited on the hit
    - float eDepError [GeV] // error measured on eDep
    - edm4hep::Vector3d position [mm] // hit position
  Types:
    - edm4hep::TrackerHit3D
    - edm4hep::TrackerHitPlane
            

Podio

Generates Event Data Model and serves as I/O Layer

• Generates EDM from YAML files
• Employs plain-old-data (POD) data structures
• I/O machinery consists of three layers
  • POD Layer - actual data structures
  • Object Layer - helps resolve the relations
  • User Layer - full fledged EDM objects
• Supports multiple backends:
  • ROOT, SIO, ...
• Current version: 0.99

Podio Reader

Constructs the EDM4hep objects for the user

Example usage of Podio Reader in Pyhton:

from podio.root_io import Reader
reader = Reader("one or many input files")
for event in reader.get("events"):
  hits = store.get("hits")
  for hit in hits:
    # ...
                  

Datasets

Plethora of processes are pre-generated and available from EOS

Need to be reprocessed to be usable with EDM4hep 1.0

• Two main production campaigns in use:
• Spring 2021 | EDM4hep v0.3.1 | Podio v0.13
• Winter 2023 | EDM4hep v0.7.2 | Podio v0.16.2
• Samples are identified by their name, e.g.: p8_ee_WW_ecm240
• The production Database is browsable at:
  fcc-physics-events.web.cern.ch
• Example samples list:
  FCCee | Winter 2023 | IDEA | Delphes events
• EOS directory:
  /eos/experiment/fcc/...
• Generation handled by EventProducer
  • Heads up: Will change soon (Dirac, iLCDirac)

EOS Space

ROOT RDataFrame

• Describes processing of data as actions on table columns
  • Defines of new columns
  • Filter rules
  • Result definitions (histogram, graph)
• The actions are lazily evaluated
• Multi threading is available out of the box
• Optimized for bulk processing
• Allows integration of existing C++ libraries

Reading EDM4hep in RDataFrame

• EDM4hep collection is read in by RDataFrame directly and presented to the user in form:
  • This is per event
  • No convenient access to relationships
• Example of a simple function:

• In the course of the analysis the EDM4hep slowly decays into more trivial objects

Relations

• One collection can contain one-to-one or one-to-many relations to other collections, e.g.:
  • CaloHit ⇶ CaloHitContribution
  • MCParticle ⇶ MCParticle
• Typically relationships between derived objects (Sim. side separated from Reco. side)
• Example analyzer (FCC Tutorials link):

Associations

• One-to-one relationships between two collection types, e.g.:
  • MCParticle ↔ ReconstructedParticle
  • SimTrackerHit ↔ TrackerHit
• Relationships between Simulation and Reconstruction side
• Example analyzer: Association between RecoParticle and MCParticle (link):