Skip to content

PFlow Jets Variable#

The following variables are defined:

Jet variables#

Variable Name Description
HadronConeExclTruthLabelChildPdgId
HadronGhostTruthLabelChildPdgId
TauDecayLabel
absEta_btagJes Jet $
eta_btagJes Jet \eta in input (D)AOD.2
isRun3
jetPtRank Rank of jet in p_{\rm T}-ordered list in event. Rank 0 corresponds to highest-p_{\rm T} jet.
primaryVertexDetectorZ
pt_btagJes Jet p_{\rm T} in input (D)AOD.2
scalarSumTrackPt
energy Energy of calibrated jet.
eta Calibrated \eta of jet.
mass Mass of calibrated jet.
phi Jet \phi.
pt Calibrated p_{\rm T} of the jet. Flavor tagging is generally quantified in terms of this variable.
NNJvt Jet vertex NN tagger score (used for pile-up rejection).
isJvtHS Truth hard-scatter label. Truth information! Do not use for training!
isJvtPU Truth pile up label. Truth information! Do not use for training!
IP3D_nTrks number of tracks used in the computation of the log-likelihood ratio discriminant
SV1_L3d distance between the primary and the secondary vertex
SV1_Lxy transverse distance between the primary and secondary vertex
SV1_N2Tpair number of two-track vertex candidates
SV1_NGTinSvx number of tracks used in the secondary vertex
SV1_correctSignificance3d corrected distance between the primary and the secondary vertex divided by its uncertainty, should be used instead of SV1_significance3d
SV1_deltaR dR between the jet axis and the direction of the secondary vertex relative to the primary vertex
SV1_dstToMatLay distance from secondary vertex to the closest material layer
SV1_efracsvx energy fraction of the tracks associated with the secondary vertex: energy of vertex / energy of jet, considering charged tracks)
SV1_isDefaults default values are filled for this object
SV1_masssvx invariant mass of tracks at the secondary vertex assuming pion mass
SV1_significance3d distance between the primary and the secondary vertex divided by its uncertainty
JetFitter_N2Tpair number of two-track vertex candidates (prior to decay chain fit)
JetFitter_dRFlightDir unknown
JetFitter_deltaR unknown
JetFitter_deltaeta pseudorapidity distance deta between sum of all momenta at vertices and the fitted B-meson flight direction
JetFitter_deltaphi azimuthal distance dphi between sum of all momenta at vertices and the fitted B-meson flight direction
JetFitter_energyFraction fraction of the charged jet energy in the secondary vertices
JetFitter_isDefaults default values are filled for this object
JetFitter_mass total invariant mass at all vertices fitted with at least two tracks (i.e. comparable to SV1 mass, secondary and tertiary vertices are merged)
JetFitter_massUncorr unknown
JetFitter_nSingleTracks number of single track vertices
JetFitter_nTracksAtVtx number of tracks from multi-prong displaced vertices
JetFitter_nVTX number of vertices with more than one track
JetFitter_significance3d significance of the average distance between PV and displaced vertices, considering all multi-prong vertices or (if there are none) of all single-track vertices.
JetFitterSecondaryVertex_averageAllJetTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_averageTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_displacement2d transverse displacement of the secondary vertex from primary vertex (PV)
JetFitterSecondaryVertex_displacement3d distance of the secondary vertex from primary vertex (PV)
JetFitterSecondaryVertex_energy energy of charged tracks associated to secondary vertex
JetFitterSecondaryVertex_energyFraction fraction of charged jet energy in secondary vertex
JetFitterSecondaryVertex_isDefaults default values are filled for this object
JetFitterSecondaryVertex_mass the invariant mass of tracks associated to a single secondary or tertiary vertex
JetFitterSecondaryVertex_maximumAllJetTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_maximumTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_minimumAllJetTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_minimumTrackRelativeEta jet fitter secondary vertex algorithm properties (no further description)
JetFitterSecondaryVertex_nTracks number of tracks associated to secondary vertex
rnnip_isDefaults default values are filled for this object
actualInteractionsPerCrossing Number of interactions per bunch crossing (\mu) for the bunch crossing this jet was associated to.
averageInteractionsPerCrossing Number of interactions per bunch crossing (\mu) averaged over this lumi block.
eventNumber Event number of the event the jet is associated with.
mcEventWeight Event weight of MC simulated event. Truth information! Do not use for training!
nPrimaryVertices Number of reconstructed primary vertices in this event.
GhostBHadronsFinalCount number of associated b hadrons, based on whether they fall into the area clustered with the jet. Truth information! Do not use for training!
GhostBHadronsFinalPt pt of associated b hadrons. Truth information! Do not use for training!
GhostCHadronsFinalCount number of associated c hadrons. Truth information! Do not use for training!
HadronConeExclExtendedTruthLabelID more detailed version of the HadronCone algorithm, with labels for double b-jets: 55 (double b-jets), 54 (bc jet). Truth information! Do not use for training!
HadronConeExclTruthLabelChildLxy Decay radius of the child hadron of the labelling particle used for HadronConeExclTruthLabelID. (i.e. the c-hadron inside a b-to-c decay). Truth information! Do not use for training!
HadronConeExclTruthLabelChildPt PDGID of the child hadron of the labelling particle used for HadronConeExclTruthLabelID (i.e. the c-hadron inside a b-to-c decay). Truth information! Do not use for training!
HadronConeExclTruthLabelDR dR(truth, jet) for the labelling particle used for HadronConeExclTruthLabelID. Truth information! Do not use for training!
HadronConeExclTruthLabelID jet label, using a geometric cone around the jet rather than the jet clustering algorithm. If a parton with a transverse momentum of more than 5 GeV is found within dR(q, jet) < 0.3 of the jet direction, the jet is labelled as a jet with the parton's flavour. The label should be one of: 0 (light jet), 4 (charm jet), 5 (bottom jet), or 15 (tau jet). Results should be similar to the ghost labeling. Truth information! Do not use for training!
HadronConeExclTruthLabelLxy Decay radius of the labelling particle used for HadronConeExclTruthLabelID. Truth information! Do not use for training!
HadronConeExclTruthLabelPdgId PDGID of the labelling particle used for HadronConeExclTruthLabelID. Truth information! Do not use for training!
HadronConeExclTruthLabelPt Transverse momentum of the labelling particle used for HadronConeExclTruthLabelID. Truth information! Do not use for training!
HadronGhostExtendedTruthLabelID more detailed version of the HadronGhostTruthLabelID, with labels for jets with two hadrons: 55 (double b-jets), 54 (bc jet), 44 (cc jet). Truth information! Do not use for training!
HadronGhostTruthLabelChildLxy Decay radius of the child hadron of the labelling particle used for HadronGhostTruthLabelID. (i.e. the c-hadron inside a b-to-c decay). Truth information! Do not use for training!
HadronGhostTruthLabelChildPt PDGID of the child hadron of the labelling particle used for HadronGhostTruthLabelID (i.e. the c-hadron inside a b-to-c decay). Truth information! Do not use for training!
HadronGhostTruthLabelDR dR(truth, jet) for the labelling particle used for HadronGhostTruthLabelID. Truth information! Do not use for training!
HadronGhostTruthLabelID Jet flavour label using ghost associated hadrons. Labelling hadrons are required to have p_T > 5 GeV. The label should be one of: 0 (light jet), 4 (charm jet), 5 (bottom jet), or 15 (tau jet). Truth information! Do not use for training!
HadronGhostTruthLabelLxy Decay radius of the labelling particle used for HadronGhostTruthLabelID. Truth information! Do not use for training!
HadronGhostTruthLabelPdgId PDGID of the labelling particle used for HadronGhostTruthLabelID. Truth information! Do not use for training!
HadronGhostTruthLabelPt Transverse momentum of the labelling particle used for HadronGhostTruthLabelID. Truth information! Do not use for training!
LeptonDecayLabel jet label for leptonic b hadron decays. The leptons from the b decay and c decay are counted. 1s in the LeptonDecayLabel represent electrons, 2s muons and 3s tau-leptons. That means LeptonDecayLabel = 1 means an electron is present in either the b- or c-decay, 11 means electrons in both decays, 112 electrons in both decays plus a muon in one of the decays,... up to technically 112233 which would theoretically mean all three leptons occur in both decays. Truth information! Do not use for training!
PartonTruthLabelDR dR(parton, jet) of the labelling parton. Truth information! Do not use for training!
PartonTruthLabelID Parton level flavour label, based on PDGID. The highest energy parton is used to label the jet. Truth information! Do not use for training!
PartonTruthLabelPt pT of the labelling parton. Truth information! Do not use for training!
n_truth_promptLepton Number of prompt leptons nearby the jet. Can be used to remove electron jets by requiring n_truth_promptLepton == 0. Truth information! Do not use for training!
DL1dv01_pb Output from DL1d, b-jet probability.1 3
DL1dv01_pc Output from the DL1d, c-jet probability.1 3
DL1dv01_pu Output from the DL1d, light-jet probability.1 3
GN2v01_pb Output from the GN2, b-jet probability.1
GN2v01_pc Output from the GN2, c-jet probability.1
GN2v01_pu Output from the GN2, light-jet probability.1
n_tracks Number of tracks associated to the jet
softMuon_dR Soft muon tagger output
softMuon_eta Soft muon tagger output
softMuon_ip3dD0 Soft muon tagger output
softMuon_ip3dD0Significance Soft muon tagger output
softMuon_ip3dD0Uncertainty Soft muon tagger output
softMuon_ip3dZ0 Soft muon tagger output
softMuon_ip3dZ0Significance Soft muon tagger output
softMuon_ip3dZ0Uncertainty Soft muon tagger output
softMuon_isDefaults Soft muon tagger output
softMuon_momentumBalanceSignificance Soft muon tagger output
softMuon_pTrel Soft muon tagger output
softMuon_phi Soft muon tagger output
softMuon_pt Soft muon tagger output
softMuon_qOverPratio Soft muon tagger output
softMuon_scatteringNeighbourSignificance Soft muon tagger output
JetFitterFlip_N2Tpair Flip tagger output, used for calibration studies
JetFitterFlip_dRFlightDir Flip tagger output, used for calibration studies
JetFitterFlip_deltaeta Flip tagger output, used for calibration studies
JetFitterFlip_deltaphi Flip tagger output, used for calibration studies
JetFitterFlip_energyFraction Flip tagger output, used for calibration studies
JetFitterFlip_mass Flip tagger output, used for calibration studies
JetFitterFlip_massUncorr Flip tagger output, used for calibration studies
JetFitterFlip_nSingleTracks Flip tagger output, used for calibration studies
JetFitterFlip_nTracksAtVtx Flip tagger output, used for calibration studies
JetFitterFlip_nVTX Flip tagger output, used for calibration studies
JetFitterFlip_significance3d Flip tagger output, used for calibration studies
DL1r20210824r22_pb High level tagger output! Do not use for training!
DL1r20210824r22_pc High level tagger output! Do not use for training!
DL1r20210824r22_pu High level tagger output! Do not use for training!
dipsLoose20220314v2_pb High level tagger output! Do not use for training!
dipsLoose20220314v2_pc High level tagger output! Do not use for training!
dipsLoose20220314v2_pu High level tagger output! Do not use for training!

Track variables#

Variable Name Description
ftagTruthSourceLabel
valid valid flag, for more robust selection, true for any track that is defined
d0 transverse impact parameter relative to PV. (aka distance of closest approach of the track to the primary vertex point in the r-phi projection). Defined here4
d0Uncertainty uncertainty on track d0
phiUncertainty uncertainty on track phi
pt track transverse momentum
qOverP track charge divided by momentum magnitude
qOverPUncertainty uncertainty on track qOverP
thetaUncertainty uncertainty on track theta
z0RelativeToBeamspot longitudinal impact parameter projected onto the direction perpendicular to the track, relative to beamspot
z0RelativeToBeamspotUncertainty uncertainty on track z0RelativeToBeamspot
z0SinTheta longitudinal impact parameter projected onto the direction perpendicular to the track, relative to the PV. Defined here4
z0SinThetaUncertainty uncertainty on track z0SinTheta
numberOfInnermostPixelLayerHits number of hits in the IBL: could be 0, 1, or 2
numberOfInnermostPixelLayerSharedHits number of shared hits (contributing to the track fit and to another track) in the IBL
numberOfInnermostPixelLayerSplitHits number of split hits in the IBL
numberOfNextToInnermostPixelLayerHits number of hits in the next-to-innermost pixel layer: could be 0, 1, or 2
numberOfPixelHits combined number of hits in the pixel layers (including the IBL)
numberOfPixelSharedHits number of shared hits (contributing to the track fit and to another track + not marked as split hit) in the pixel layers (including the IBL)
numberOfPixelSplitHits number of split hits in the pixel layers (including the IBL; split hit = hit is identified as being created by multiple charged particles during ambiguity solver stage at pattern recognition level)
numberOfSCTHits combined number of hits in the SCT layers (since 2 strip hits are required for a full SCT spacepoint, this number is divided by two in the track selection)
numberOfSCTSharedHits Number of shared hits (contributing to the track fit and to another track) in the SCT layers (since 2 strip hits are required for a full SCT spacepoint, this number is divided by two in the track selection)
deta pseudorapidity distance between track and jet
dphi azimuthal angle distance between track and jet
ptfrac fraction of the jet pt carried by the track
lifetimeSignedD0 The lifetime-signed transverse impact parameter.6
lifetimeSignedD0Significance The lifetime-signed track d_0 significance (d_{0} / \sigma_{d_{0}}).6
lifetimeSignedZ0SinTheta The lifetime-signed longitudinal impact parameter, multiplied by \sin \theta.6
lifetimeSignedZ0SinThetaSignificance The lifetime-signed track z_0 significance (z_{0} \sin \theta / \sigma_{z_{0} \sin \theta}).6
AMVFWeightPV compatability of the track with the primary vertex if the track was used in the primary vertex fit (0 if the track was not used in the primary vertex fit)
JFVertexIndex index of JF vertex if this track was used in the construction of a JF vertex (defaults to -2)
SV1VertexIndex index of SV1 vertex if this track was used in the construction of a SV1 vertex (defaults to -2)
leptonID +-11 if the track was used in the reconstruction of an electron. +-13 for muon. If a track was not used in the reconstruction of a electron or muon, then 0.
ftagTruthBarcode generator level truth barcode of the truth particle linked to this track (if one exists), used for linking between different objects
ftagTruthOriginLabel Truth origin of the track.5
ftagTruthParentBarcode barcode of the parent B/C hadron (if one exists) of the truth particle linked to this track (if one exists). If no truth particles are linked to this track a value of -1 is returned. A value of -2 indicates that there is a truth particle linked to the track but it is not a B/C hadron. Used for linking to particles in the truth_hadrons dataset.
ftagTruthTypeLabel truth type of the track (NoTruth=0, Other=1, Pion=2, Kaon=3, Electron=4, Muon=5, Photon=6). Defined here
ftagTruthVertexIndex truth vertex index of the track. 0 is reserved for the truth PV, any SVs are indexed arbitrarily with a int >0. Truth vertices within 0.1mm are merged.

Truth variables#

Variable Name Description
Lxy
barcode
charge
decayVertexDEta
decayVertexDPhi
decayVertexX
decayVertexY
decayVertexZ
deta
dphi
dr
energy
eta
flavour
ftagTruthParentBarcode
mass
pdgId
phi
pt
valid

Truth variables#

Variable Name Description
mass
valid validity flag, for more robust selection, true for any truth particle that is defined
Lxy truth particle decay displacement7
charge truth particle charge
decayVertexDEta truth particle decay \eta offset, relative to the jet axis7
decayVertexDPhi truth particle decay \phi offset, relative to the jet axis7
decayVertexX X component of the truth particle decay displacement7
decayVertexY Y component of the truth particle decay displacement7
decayVertexZ Z component of the truth particle decay displacement7
deta pseudorapidity distance between truth particle and jet
dphi azimuthal angle distance between truth particle and jet
dr truth particle dR(particle, jet)
energy truth particle energy
eta truth particle pseudorapidity
phi truth particle azimuthal angle
pt truth particle transverse momentum
barcode generator level barcode of the truth particle, used to link to objects in other datasets
flavour 5 if the truth particle is a B hadron, 4 if the truth particle is a C hadron, -1 otherwise.
ftagTruthParentBarcode barcode of the parent B hadron (if one exists) of the truth particle.
pdgId truth particle pdgId

Please reach out to the flavour tagging group if you have any questions:

ATLAS FTAG mattermost channel


  1. This is a high-level output from a neural network. It should not be considered a stable input to design new taggers. 

  2. In production, flavor tagging algoirhtms run before the final jet calibration is applied.The jet energy scale at this stage is set by the jet calibration which is applied when jets are built.Jets saved in DAODs are calibrated to this scale as well.For consistency, we use this jet energy scale in the training as well. 

  3. The DL1 series includes DL1, DL1r, and DL1d. These are legacy taggers which are not recommended for physics analysis. They are included here only for comparison. 

  4. The conventional d_0 takes the sign of (\vec{p}_0 \times \vec{d}_0) \cdot \hat{z}, where \vec{d}_0 is the transverse track displacement at the closest approach to the primary vertex and \vec{p}_0 is the momentum at that point. 

  5. Tracks labels: 0 = pileup, 1 = fake, 2 = prompt, 3 = from b-hadron, 4 = from c child of a b hadron, 5 = from c-hadron, 6 = from \tau lepton, 7 = from other secondary decay. See InDetTrackTruthOriginDefs for ore information. 

  6. The lifetime signed impact parameters are given a positive sign if |\phi_0 - \phi_{\mathrm{jet}}| < \pi / 2 and a negative sign otherwise, where \phi_0 and \phi_{\mathrm{jet}} are the \phi components of the track displacement and the jet momentum, respectively. 

  7. For truth variables the displacement is defined as the decay vertex position, relative to the production vertex for the simulated event.