What is the difference between e.g. EcalEndcapNClusters and EcalEndcapPClusters?

[wdconinc]

In the reconstructed data files I see collections like "*NClusters" and "*PClusters", for example: "EcalEndcapNClusters" and "EcalEndcapPClusters"? What is the difference and how do I interpret the content of the reconstructed data files?

[wdconinc]

Collections of reconstructed quantities have a standardized naming scheme, typically as follows:

• *Hits, e.g. EcalEndcapNHits: a collection of SimCalorimeterHit objects, i.e. geant4 hits (for calorimeters this is integrated over a unit of segmentation with individual energy contributions accessible as well),
• *RawHits, e.g. EcalEndcapNRawHits: a collection of RawCalorimeterHit objects, i.e. digitized hits representing TDC and/or QDC values within a dynamic range and bit precision,
• *RecHits, e.g. EcalEndcapNRecHits: a collection of CalorimeterHit objects, i.e. reconstructed hits recreated from a digitized hit after pedestal subtraction and calibration,
• *ProtoClusters, e.g. EcalEndcapNTruthProtoClusters: a collection of ProtoCluster objects, i.e. hits likely to be part of the same cluster,
• *Clusters, e.g. EcalEndcapNClusters: a collection of Cluster objects, i.e. a fully reconstructed cluster with positions, intrinsic theta, phi, and shape parameters,
• *Assoc, e.g. EcalEndcapNClustersAssoc: a collection of MCReco*ParticleAssociation association data types, i.e. the connection between 'truth' and reconstructed data types.

The central detector systems also follow a standard naming scheme, typically as follows:

• *EndcapN* describes the negative z endcap, which is the direction in which the electron beam leaves the detector (also called the electron endcap),
• *EndcapP* describes the positive z endcap, which is the direction in which the proton/ion beam leaves the detector (also called the proton endcap),
• *Barrel* describes the barrel region.