Data description Datasets generated using Key4HEP and the CLD detector model for FCC-ee suitable for particle flow reconstruction studies. The datasets contain generator particles, reconstructed tracks and calorimeter hits, reconstructed Pandora PF particles and their respective links in the EDM4HEP format. The following processes have been simulated with Pythia 8: p8_ee_tt_ecm365: ee -> ttbar, center of mass energy at 365 GeV The detector simulation has been done with Geant4, the reconstruction with Marlin interfaced via Key4HEP which includes PF reconstruction with Pandora, all using publicly available models and code. Contents This record includes the following files: p8_ee_tt_ecm365_rootfiles.tgz: small subset of files suitable for testing dataset_full.txt: the full list of files, hosted on the EOS storage system at CERN, ~2TB total p8_ee_tt_ecm365.cmd: the Pythia8 card pythia.py: the pythia steering code for Key4HEP run_sim.sh: the steering script for generating, simulating and reconstructing a single file of 100 events from the p8_ee_tt_ecm365 PandoraSettings.zip: the settings used for Pandora PF reconstruction CLDReconstruction.py: the steering configuration of the reconstruction modules in Key4HEP cld_steer.py: the steering configuration of the Geant4 simulation modules in Key4HEP Dataset semantics Each file consists of event records. Each event contains structured branches of the relevant physics data. The branches relevant to particle flow reconstruction include: MCParticles: the ground truth generator particles ECALBarrel, ECALEndcap, ECALOther, HCALBarrel, HCALEndcap, HCALOther, MUON: reconstructed hits in the various calorimeter subsystems SiTracks_Refitted: the reconstructed tracks PandoraClusters: the calorimeter hits, clustered by Pandora to calorimeter clusters MergedRecoParticles: the reconstructed particles from the Pandora particle flow algorithm CalohitMCTruthLink: the links between MC particles and reconstructed calorimeter hits SiTracksMCTruthLink: the links between MC particles and reconstructed tracks The full details of the EDM4HEP format are available here. Dataset characteristics The p8_ee_tt_ecm365_rootfiles.tgz consists of about 50k events stored in a total of 500 files, 22GB in the ROOT EDM4HEP format. The full dataset is hosted on the EOS storage system at CERN, ~2TB total. Detector geometry The key4hep CLD geometry version used to generate the events is CLD_o2_v05 and can be found on github here. How can you use these data? The ROOT files can be directly loaded with the uproot Python library. Disclaimer These are simulated samples suitable for conceptual machine learning R&D and software performance studies. They have not been calibrated with respect to real data, and should not be used to derive physics projections about the detectors. Neither FCC nor CERN endorse any works, scientific or otherwise, produced using these data. All releases will have a unique DOI that you are requested to cite in any applications or publications.