LF Augmentation Tool


Due to slimming some truth information is lost after derivation level so a tool to obtain N-particles and N-tracks relevant to FTAG light-flavour calibration has been developed.This tool augments the jets with these counts for Ks, Lambda, s-hadrons, photon conversions, material interactions and fakes so that they are accesible after derivation. The code for this can be found here.


This tool was developed for LF calibration studies so currently only exists in FTAG1 for EMTopo and EMPFlow and was tested on one set of di-jet samples, an example of a slice from this sample is mc16_13TeV.361020.Pythia8EvtGen_A14NNPDF23LO_jetjet_JZ0W.merge.AOD.e3569_s3126_r10211_r10210

There is no reason this tool shouldn't work for other samples but take care to check enough truth information is accessible that the definitions are still valid, especially for fakes. If your number of fakes are unusually high then it is likely it is failing to find necessary truth information. This tool will only crash if no b-tag object is found.

Object Definitions

This tool only looks at tracks from three low-level b-tag algorithms: SV1, IP3D and JetFitter. Care has been taken to prevent double counting tracks that may appear from more than one of these.

Accessors for these are in bold next to definition


Fake tracks have been divided into three relevent sub-categories

  1. Hard-scatter tracks: truth link && TruthMatchProb > 0.5 (HS)
  2. Hard-scatter fakes: truth link && TruthMatchProbb < 0.5 (FakeHS)
  3. Pile-Up: No truth link (NTruthLink)
NOTE: Pile-up is the category that requires special care as any track without a truth link will end up in this augmentation. This is as samples are generally set-up, the only truth links missing should be pile-up but this is not true for all samples.

Material Interactions

If the track truth barcode > 200 000 && no decay in flight && no photon conversion && no strange hadron then it is defined as a material interaction (MatInt)

Photon Conversion

A electron or positron with only one parent, the parent has to be a photon. This augmentation has two decorations:

  1. Number of photon tracks (Conversion)
  2. Number of particles (nConversion)


Once again a few decorators exist for this augmentation

  1. K-short: pi+ or pi- with Kshort as a parent
    • Number of K-short tracks (K_short)
    • Number of K-short particles (nK_short)
  2. Lambda: proton or pi- with a Lambda parent
    • Number of Lambda tracks (Lambda)
    • Number of Lambda particles (nLambda)
  3. s-Hadrons: K-short, Lambda(0), Sigma(0) Sigma(_), Sigma(-), Xi(0), Xi(-), Omega(-) or K-long
    • Number of s-hadron tracks (s_hadron)
    • Number of s-hadron particles (ns_hadron)

-- CandiceRuthBasson - 2020-07-02

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Topic revision: r2 - 2020-07-02 - CandiceRuthBasson
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