The Class ID (CLID)

A CLID is a number that identifies uniquely an LHCb event data class. This number is used by the Gaudi framework to select what Converter to use when reading or writing event data files and what graphical Converter to use for visualisation. The number allocated to each data object class should be unique and permanent to ensure that we can write and later read data files correctly.

The CLID has a range from 0 to 65536. The range 0-99 are reserved to the Gaudi framework itself.

Class ID allocation

Since CLIDs must be unique, it is important that we keep track of allocated numbers, including obsolete ones that may have been used in existing persistent files. The allocated CLIDs are listed in the table below. When creating a new event data class, please choose a not yet allocated CLID in the appropriate range and document it in the table below.

List of CLIDs allocated for LHCb Event model classes

Sub-System	Class	CLID	TDS path (after /Event/)
Gaudi	Reserved	0-100
Headers	EventHeader	101	OBSOLETE
	GenHeader	102	Gen/Header
	ProcessHeader	103	Dummy
	MCHeader	104	MC/Header
	RecHeader	105	Rec/Header
	RecSummary	106	Rec/Summary
	Gaudi::Counter	150
	Gaudi::Counters	151
	Gaudi::Numbers	152
Gaudi	ContainedObject	190
MC	BeamParameters	200
	Collision	201	OBSOLETE
	HepMCEvent	202	Gen/HepMCEvents
	HardInfo	203	OBSOLETE
	GenCollision	204	Gen/Collisions
	MCParticle	210	MC/Particles
	GenMCLink	211	OBSOLETE
	MCVertex	220	MC/Vertices
	MCHit	230	MC/<det>/Hits
	MCExtendedHit	231	MC/<det>/Hits
	MCSensPlaneHit	232	MC/Ecal/SensPlaneHits
	MCRichRadiatorHit	240	OBSOLETE
	MCRichPhotodetectorHit	241	OBSOLETE
	MCEffTree	250	MC/<context>/EffTrees
	GhostTrackInfo	299
	MCProperty	300	MC/TrackInfo
	LinksByKey	400	Link/xxx
	IntLink	500	OBSOLETE
Phys	Particle	801	Phys/User/Particles
			Phys/Prod/Particles
	Vertex	802	Phys/User/Vertices
			Phys/Prod/Vertices
			Phys/PrimaryVertices
	ProtoParticle	803	Rec/ProtoP/Final
			Rec/ProtoP/Charged
			Rec/ProtoP/Neutrals
	PrimVertex	804	OBSOLETE
	FlavourTag	805	Phys/User/Tags
			Phys/Prod/Tags
	V0	806	OBSOLETE
	AxPartCandidate	810	OBSOLETE
	VertexBase	811
	SelResult	860	Phys/Selections
	FilterCriterionResult	861	Phys/FilterCriteria
	EffCheckResult	870	OBSOLETE
	Particle2LHCbIDs	880
	Particle2VertexBase	881
	Particle2UnsignedInts	882
	SwimmingReport	900	Swimming/Reports
	TurningPoint	901
DAQ	RawBuffer	1001	OBSOLETE
	RawEvent	1002	DAQ/RawEvent
	L1Buffer	1003	OBSOLETE
	L1Event	1004	OBSOLETE
	ODIN	1005	DAQ/ODIN
DST	PackedMCParticle	1510	pSim/MCParticles
	PackedMCVertex	1511	pSim/MCVertices
	PackedCollision	1512	pSim/Collisions
	PackedMCRichHit	1521	pSim/Rich/Hits
	PackedMCRichOpticalPhoton	1522	pSim/Rich/OpticalPhotons
	PackedMCRichSegment	1523	pSim/Rich/Segments
	PackedMCRichTrack	1524	pSim/Rich/Tracks
	PackedMCHit	1525	pSim/<Det>/Hits
	PackedMCCaloHit	1526	pSim/<Det>/Hits
	PackedMCRichDigitSummary	1527	pSim/Rich/DigitSummaries
	PackedCluster	1540	pRec/Track/Clusters
	PackedCaloCluster	1541	pRec/Calo/Cluster
	PackedCaloDigit	1542	pRec/<Det>/Digits
	PackedCaloAdc	1543	pRec/<Det>/Adcs
	PackedTrack	1550	pRec/Track/Best
			pRec/Track/Muon
	PackedCaloHypo	1551	pRec/Calo/Photons
			pRec/Calo/Electrons
			pRec/Calo/MergedPi0s
			pRec/Calo/SplitPhotons
	PackedProtoParticle	1552	pRec/ProtoP/Charged
			pRec/ProtoP/Neutral
	PackedRecVertex	1553	pRec/Vertex/Primary
	PackedTwoProngVertex	1554	pRec/Vertex/V0
	PackedWeightsVector	1555	pRec/Vertex/Weights
	PackedDecReport	1559	pStrip/Phys/DecReports
	PackedRelations	1560	pPhys/Relations
	PackedRichPIDs	1561	pRec/Rich/PIDs
	PackedWeightRelations	1562	pPhys/Relations
	PackedMuonPIDs	1571	pRec/Muon/MuonPID
	PackedParticle	1581	pPhys/Particles
			pPhys/User/Particles
	PackedVertex	1582	pPhys/Vertices
			pPhys/User/Vertices
	PackedFlavourTag	1583	pPhys/FlavourTags
	PackedRelatedInfoRelations	1584	pPhys/PartToRelatedInfoRelations
			pPhys/User/PartToRelatedInfoRelations
	PackedParticle2Ints	1591	pPhys/Particle2Int
Calo	MCCaloHit	2000	MC/<Det>/Hits
	MCCaloDigit	2001	MC/<Det>/Digits
	CaloDigit	2002	Raw/<Det>/Digits
	CaloCluster	2003	Rec/Calo/xxxClusters
	CaloHypo	2004	Rec/Calo/<Hypothesis>
	CaloParticle	2005	OBSOLETE
	MCCaloSensPlaneHit	2006	OBSOLETE
	CaloADC	2007	Raw/<Det>/Adcs
			Raw/<Det>/FullAdcs
	CaloCellID	2008
Bcm	MCBcmDigit	3000	MC/Bcm/Digits
	BcmDigit	3001	Raw/Bcm/Digits
Velo	MCVeloHit	4001	OBSOLETE
	MCVeloFE	4002	MC/Velo/FE
			MC/Velo/PuFE
	VeloFullFPGADigit	4003	OBSOLETE
	VeloCluster	4004	OBSOLETE
	VeloBankHeader	4005
	VeloCluster	4006	Raw/Velo/Clusters
	VeloDecodeStatus	4009
	InternalVeloCluster	4104	OBSOLETE
VeloPix	MCVeloPixDeposit	4501	MC/VeloPix/Deposits
	MCVeloPixDigit	4502	MC/VeloPix/Digits
	VeloPixDigit	4503	Raw/VeloPix/Digits
	VeloPixCluster	4504	Rec/VeloPix/Clusters
Framework	AlgUsedTime - Until Brunel v15r0	5000	OBSOLETE
	ProcStatus	5001	Rec/Status
	AlgUsedTime - From Brunel v15r1	5002	OBSOLETE
L0	L0CaloCandidate	6001	Trig/L0/Calo
	L0MuonCandidate	6002	Trig/L0/Muon
	L0MuonData	6003	Trig/L0/MuonData
	L0DUReport	6004	Trig/L0/Decision
	L0CaloAdc	6006	Trig/L0/EcalRaw
			Trig/L0/HcalRaw
	L0PrsSpdHit	6007	Trig/L0/PrsRaw
			Trig/L0/SpdRaw
	L0MuonCtrlError	6008	Trig/L0/MuonCtrlError
	L0MuonInfo	6009	Trig/L0/MuonInfo
	L0MuonProcError	6010	Trig/L0/MuonProcError
	L0MuonError	6011	Trig/L0/L0MuonError
L1	L1Raw	7001	OBSOLETE
	L1Cluster	7002	OBSOLETE
	L1Track2d	7003	OBSOLETE
	L1Track3d	7004	OBSOLETE
	L1Vertex2d	7005	OBSOLETE
	L1Vertex3d	7006	OBSOLETE
	L1Summary	7007	OBSOLETE
	L1Report	7008	OBSOLETE
	L1STCluster	7009	OBSOLETE
	L1OTCluster	7010	OBSOLETE
	L1MCTruth	7011	OBSOLETE
	L1Score	7100	OBSOLETE
	TrgDecision	7101	OBSOLETE
	HltScore	7102	OBSOLETE
HLT	HltTrack	7501	OBSOLETE
	HltVertex	7502	OBSOLETE
	HtlSummary	7510	OBSOLETE
	HtlLumiResult	7515	Hlt/LumiResult
	HltLumiSummary	7520	Hlt/LumiSummary
	HltDecReports	7521	Hlt/(Emu/)DecReports
	HltObjectSummary	7530	Hlt/(Emu/)SelReports/Candidates
	HltSelReports	7531	Hlt/(Emu/)SelReports
	HltVertexReports	7551	Hlt(Emu)/VertexReports
	Hlt::Candidate	7561
	Hlt::Stage	7562
	Hlt::L0DUMuon	7563
	Hlt::MultiTrack	7564
Trg	TrgCaloCluster	7600	OBSOLETE
	TrgCaloParticle	7601	OBSOLETE
	TrgTrack	7700	OBSOLETE
	TrgVertex	7701	OBSOLETE
	TamperingResults	7800	OBSOLETE
OT	OTDigit	8001	OBSOLETE
	OTTime	8001	Raw/OT/Times
	MCOTDigit	8002	OBSOLETE
	MCOTTime	8002	MC/OT/Times
	MCOTDeposit	8003	MC/OT/Deposits
	OTCluster	8004	OBSOLETE
ST	MCSTDeposit	9001	MC/<det>/Deposits
	MCSTDigit	9002	MC/<det>/Digits
	STDigit	9003	Raw/<det>/Digits
	STCluster	9004	Rec/<det>/Clusters
	STSummary	9005	Rec/<det>/Summary
	STL1Cluster	9006	OBSOLETE
	STTELL1Data	9010	Raw/<det>/<bankType>
	STELL1EventInfo	9011	Raw/<det>/EventInfo
	STTELL1Error	9012	Raw/<det>/Error
	STTELL1BoardErrorBank	9013	Raw/<det>/ErrorTELL1
Tr	TrFitTrack	10002	OBSOLETE
	TrStoredTrack	10003	OBSOLETE
	TrStateL	10004	OBSOLETE
	TrStateP	10005	OBSOLETE
	ITClusterOnStoredTrack	10006	OBSOLETE
	OTClusterOnStoredTrack	10007	OBSOLETE
	VeloClusterOnStoredTrack	10008	OBSOLETE
	Track	10010	Rec/Track/Best
	State	10011	Rec/Track/States
	TrackVertex	10020	OBSOLETE
	RecVertex	10030	Hlt/Vertex/PV2D
			Hlt/Vertex/PV3D
			Rec/Vertex/Primary
	WeightsVector	10031	Rec/Vertex/Weights
	TwoProngVertex	10040	Rec/Vertex/V0
Muon	MCMuonHit	11020	OBSOLETE
	MuonDigit	11021	Raw/Muon/Digits
	MCMuonDigit	11022	MC/Muon/Digits
	MuonCoord	11040	Rec/Muon/Coords
	MuonCluster	11041	Raw/Muon/Cluster
	MuonPID	11050	Rec/Muon/MuonPID
Rich	RichPIDAlgBase	12401	OBSOLETE
	RichPID	12402	Rec/Rich/PIDs
	RichGlobalPID	12403	OBSOLETE
	RichRingFinderPID	12404	OBSOLETE
	RichLocalPID	12405	OBSOLETE
	RichPIDHistory	12406	OBSOLETE
	RichDigit	12407	Raw/Rich/Digits
	MCRichDigit	12408	MC/Rich/Digits
	MCRichDigitSummary	12409	MC/Rich/DigitSummaries
	MCRichDeposit	12410	OBSOLETE
	MCRichOpticalPhoton	12412	MC/Rich/OpticalPhotons
	MCRichHit	12413	MC/Rich/Hits
	MCRichTrack	12415	MC/Rich/Tracks
	RichSummaryTrack	12451	Rec/Rich/Rich<method>SummaryTracks
Herschel	HCDigit	13001	Raw/HC/Digits
			Raw/HC/L0Digits
FSR	LumiCounters	13500
	LumiFSR	13501
	LumiIntegral	13502
	EventCountFSR	13503
	TimeSpanFSR	13504
	LumiMethods	13505
	GenCountersFSR	13600
	GenFSR	13601
Plume	PlumeAdc	14100	Raw/Plume/Adcs
	MCPlumeDigit	14150	MC/Plume/Digits
Minerva	RESERVED	50000-50999
Daya Bay	RESERVED	51000-51999
Gaudi	RESERVED	>65535