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[ALICE3] Use cascade track from fitter instead of smeared track #15011

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njacazio merged 2 commits into from
Feb 17, 2026
+42 −25
Merged

[ALICE3] Use cascade track from fitter instead of smeared track #15011

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58b12dd
Use cascade track from fitter instead of smeared track
jesgum Feb 17, 2026
7f548fc
update
jesgum Feb 17, 2026
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67 changes: 42 additions & 25 deletions ALICE3/TableProducer/OTF/onTheFlyTracker.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -169,6 +169,7 @@ struct OnTheFlyTracker {
Configurable<bool> findXi{"findXi", false, "if decayXi on, find Xi and fill Tracks table also with Xi"};
Configurable<bool> trackXi{"trackXi", false, "if findXi on, attempt to track Xi"};
Configurable<bool> doXiQA{"doXiQA", false, "QA plots for when treating Xi"};
Configurable<int> minStraTrackHits{"minStraTrackHits", 1, "if trackXi, set min strangeness tracking hits"};
Configurable<int> doKinkReco{"doKinkReco", 0, "Flag for kink reco setting: 0 - disabled, 1 - complementary, 2 - only"};
} cascadeDecaySettings;

Expand Down Expand Up @@ -232,6 +233,8 @@ struct OnTheFlyTracker {
int negativeId; // track index in the Tracks table
int bachelorId; // track index in the Tracks table

float pt;
float eta;
float dcaV0dau;
float dcacascdau;
float v0radius;
Expand Down Expand Up @@ -432,6 +435,7 @@ struct OnTheFlyTracker {
// basic mass histograms to see if we're in business
insertHist(histPath + "hMassLambda", "hMassLambda", {kTH1F, {{axes.axisLambdaMass}}});
insertHist(histPath + "hMassXi", "hMassXi", {kTH1F, {{axes.axisXiMass}}});
insertHist(histPath + "h2dMassXi", "h2dMassXi", {kTH2F, {{axes.axisXiMass}, {axes.axisMomentum}}});

// OTF strangeness tracking QA
insertHist(histPath + "hFoundVsFindable", "hFoundVsFindable", {kTH2F, {{10, -0.5f, 9.5f}, {10, -0.5f, 9.5f}}});
Expand Down Expand Up @@ -773,18 +777,16 @@ struct OnTheFlyTracker {

cascadeDecayProducts.clear();
v0DecayProducts.clear();

if (cascadeDecaySettings.decayXi) {
if (mcParticle.pdgCode() == kXiMinus) {
o2::track::TrackParCov xiTrackParCov;
o2::upgrade::convertMCParticleToO2Track(mcParticle, xiTrackParCov, pdgDB);
decayCascade(mcParticle, xiTrackParCov, cascadeDecayProducts, xiDecayVertex, laDecayVertex);
if (cascadeDecayProducts.size() != 3) {
LOG(fatal) << "Xi decay did not produce 3 daughters as expected!";
}
xiDecayRadius2D = std::hypot(xiDecayVertex[0], xiDecayVertex[1]);
laDecayRadius2D = std::hypot(laDecayVertex[0], laDecayVertex[1]);
const bool isCascade = mcParticle.pdgCode() == kXiMinus;
if (cascadeDecaySettings.decayXi && isCascade) {
o2::track::TrackParCov xiTrackParCov;
o2::upgrade::convertMCParticleToO2Track(mcParticle, xiTrackParCov, pdgDB);
decayCascade(mcParticle, xiTrackParCov, cascadeDecayProducts, xiDecayVertex, laDecayVertex);
if (cascadeDecayProducts.size() != 3) {
LOG(fatal) << "Xi decay did not produce 3 daughters as expected!";
}
xiDecayRadius2D = std::hypot(xiDecayVertex[0], xiDecayVertex[1]);
laDecayRadius2D = std::hypot(laDecayVertex[0], laDecayVertex[1]);
}
const bool isV0 = std::find(v0PDGs.begin(), v0PDGs.end(), mcParticle.pdgCode()) != v0PDGs.end();

Expand All @@ -802,7 +804,7 @@ struct OnTheFlyTracker {

const bool longLivedToBeHandled = std::find(longLivedHandledPDGs.begin(), longLivedHandledPDGs.end(), std::abs(mcParticle.pdgCode())) != longLivedHandledPDGs.end();
const bool nucleiToBeHandled = std::find(nucleiPDGs.begin(), nucleiPDGs.end(), std::abs(mcParticle.pdgCode())) != nucleiPDGs.end();
const bool pdgsToBeHandled = longLivedToBeHandled || (enableNucleiSmearing && nucleiToBeHandled) || (cascadeDecaySettings.decayXi && mcParticle.pdgCode() == kXiMinus) || (v0DecaySettings.decayV0 && isV0);
const bool pdgsToBeHandled = longLivedToBeHandled || (enableNucleiSmearing && nucleiToBeHandled) || (cascadeDecaySettings.decayXi && isCascade) || (v0DecaySettings.decayV0 && isV0);
if (!pdgsToBeHandled) {
continue;
}
Expand All @@ -828,7 +830,7 @@ struct OnTheFlyTracker {
break;
}
}
if (cascadeDecaySettings.doXiQA && mcParticle.pdgCode() == kXiMinus) {
if (cascadeDecaySettings.doXiQA && isCascade) {
getHist(TH2, histPath + "hGenXi")->Fill(xiDecayRadius2D, mcParticle.pt());
getHist(TH2, histPath + "hGenPiFromXi")->Fill(xiDecayRadius2D, cascadeDecayProducts[0].Pt());
getHist(TH2, histPath + "hGenPiFromLa")->Fill(laDecayRadius2D, cascadeDecayProducts[1].Pt());
Expand Down Expand Up @@ -870,7 +872,7 @@ struct OnTheFlyTracker {
std::vector<int> nTPCHits(kCascProngs); // TPC type

bool tryKinkReco = false;
if (cascadeDecaySettings.decayXi && mcParticle.pdgCode() == kXiMinus) {
if (cascadeDecaySettings.decayXi && isCascade) {
bool reconstructedCascade = false;
if (cascadeDecaySettings.doXiQA) {
getHist(TH1, histPath + "hXiBuilding")->Fill(0.0f);
Expand Down Expand Up @@ -1042,6 +1044,8 @@ struct OnTheFlyTracker {
cascadeTrack.setPID(o2::track::PID::XiMinus); // FIXME: not OK for omegas

thisCascade.cascradiusMC = xiDecayRadius2D;
thisCascade.pt = cascadeTrack.getPt();
thisCascade.eta = cascadeTrack.getEta();
thisCascade.findableClusters = 0;
thisCascade.foundClusters = 0;

Expand Down Expand Up @@ -1107,6 +1111,10 @@ struct OnTheFlyTracker {
}
}

if (thisCascade.foundClusters < cascadeDecaySettings.minStraTrackHits) {
continue; // We didn't find enough hits for strangeness tracking
}

// add cascade track
thisCascade.cascadeTrackId = lastTrackIndex + tracksAlice3.size(); // this is the next index to be filled -> should be it
tracksAlice3.push_back(TrackAlice3{cascadeTrack, mcParticle.globalIndex(), time, timeResolutionUs, false, false, 1, thisCascade.foundClusters});
Expand Down Expand Up @@ -1168,6 +1176,12 @@ struct OnTheFlyTracker {
}
}

fitter.propagateTracksToVertex(); // propagate e and K to D vertex
if (!fitter.isPropagateTracksToVertexDone()) {
kinkFitterOK = false;
}

o2::track::TrackParCov newCascadeTrack = fitter.getTrack(0); // (cascade)
std::array<float, 3> kinkVtx = {-999, -999, -999};
kinkVtx = fitter.getPCACandidatePos();

Expand All @@ -1181,11 +1195,13 @@ struct OnTheFlyTracker {
thisCascade.mLambda = o2::constants::physics::MassLambda;
thisCascade.findableClusters = nCascHits;
thisCascade.foundClusters = nCascHits;
thisCascade.pt = newCascadeTrack.getPt();
thisCascade.eta = newCascadeTrack.getEta();
thisCascade.mXi = RecoDecay::m(std::array{std::array{pBach[0], pBach[1], pBach[2]},
std::array{pV0[0], pV0[1], pV0[2]}},
std::array{o2::constants::physics::MassPionCharged, o2::constants::physics::MassLambda});

tracksAlice3.push_back(TrackAlice3{trackedCasc, mcParticle.globalIndex(), time, timeResolutionUs, false, false, 1, thisCascade.foundClusters});
tracksAlice3.push_back(TrackAlice3{newCascadeTrack, mcParticle.globalIndex(), time, timeResolutionUs, false, false, 1, thisCascade.foundClusters});

// add this cascade to vector (will fill cursor later with collision ID)
cascadesAlice3.push_back(thisCascade);
Expand All @@ -1198,8 +1214,9 @@ struct OnTheFlyTracker {
getHist(TH2, histPath + "hRecoXi")->Fill(xiDecayRadius2D, mcParticle.pt());
getHist(TH1, histPath + "hMassLambda")->Fill(thisCascade.mLambda);
getHist(TH1, histPath + "hMassXi")->Fill(thisCascade.mXi);
// getHist(TH2, histPath + "h2dDeltaPtVsPt")->Fill(trackParCov.getPt(), cascadeTrack.getPt() - trackParCov.getPt());
// getHist(TH2, histPath + "h2dDeltaEtaVsPt")->Fill(trackParCov.getPt(), cascadeTrack.getEta() - trackParCov.getEta());
getHist(TH2, histPath + "h2dMassXi")->Fill(thisCascade.mXi, thisCascade.pt);
getHist(TH2, histPath + "h2dDeltaPtVsPt")->Fill(thisCascade.pt, mcParticle.pt() - thisCascade.pt);
getHist(TH2, histPath + "h2dDeltaEtaVsPt")->Fill(thisCascade.pt, mcParticle.eta() - thisCascade.eta);
getHist(TH2, histPath + "hFoundVsFindable")->Fill(thisCascade.findableClusters, thisCascade.foundClusters);
}
if (isReco[0]) {
Expand Down Expand Up @@ -1570,20 +1587,20 @@ struct OnTheFlyTracker {
}
if (cascadeDecaySettings.doXiQA) {
if (trackParCov.isUsedInCascading == 1) {
getHist(TH2, histPath + "h2dDCAxyCascade")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascade")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAxyCascade")->Fill(trackParametrization.getPt(), dcaXY * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascade")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
}
if (trackParCov.isUsedInCascading == 2) {
getHist(TH2, histPath + "h2dDCAxyCascadeBachelor")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadeBachelor")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAxyCascadeBachelor")->Fill(trackParametrization.getPt(), dcaXY * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadeBachelor")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
}
if (trackParCov.isUsedInCascading == 3) {
getHist(TH2, histPath + "h2dDCAxyCascadeNegative")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadeNegative")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAxyCascadeNegative")->Fill(trackParametrization.getPt(), dcaXY * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadeNegative")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
}
if (trackParCov.isUsedInCascading == 4) {
getHist(TH2, histPath + "h2dDCAxyCascadePositive")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadePositive")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAxyCascadePositive")->Fill(trackParametrization.getPt(), dcaXY * 1e+4); // in microns, please
getHist(TH2, histPath + "h2dDCAzCascadePositive")->Fill(trackParametrization.getPt(), dcaZ * 1e+4); // in microns, please
}
}
tableTracksDCA(dcaXY, dcaZ);
Expand Down
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