[Strangeness tracking] Enable 3body strangeness tracking by default (#13182)

* Enable 3body strangeness tracking by default

* Add 3body tracking process in SVertexer

* Formatting

(cherry picked from commit 40b4132)

Author: creetz16

Detectors/Vertexing/StrangenessTracking/include/StrangenessTracking/StrangenessTrackingConfigParam.h

@@ -33,7 +33,7 @@ struct StrangenessTrackingParamConfig : public o2::conf::ConfigurableParamHelper
   float mMaxChi2 = 50;         // Maximum matching chi2
   bool mVertexMatching = true; // Flag to enable/disable vertex matching
   bool mSkipTPC = true;        // Flag to enable/disable TPC only tracks
-  bool mSkip3Body = true;      // Flag to enable/disable Decay3Body tracking
+  bool mSkip3Body = false;     // Flag to enable/disable Decay3Body tracking
 
   O2ParamDef(StrangenessTrackingParamConfig, "strtracker");
 };

Detectors/Vertexing/StrangenessTracking/src/StrangenessTracker.cxx

@@ -242,58 +242,62 @@ void StrangenessTracker::processCascade(int iCasc, const Cascade& casc, const Ca
 
 void StrangenessTracker::process3Body(int i3Body, const Decay3Body& dec3body, const Decay3BodyIndex& dec3bodyIdx, int iThread)
 {
-  ClusAttachments structClus;
-  auto& daughterTracks = mDaughterTracks[iThread];
-  daughterTracks.resize(3); // resize to 3 prongs
-
-  StrangeTrack strangeTrack;
-  strangeTrack.mPartType = dataformats::kStrkThreeBody;
-  auto dec3bodyR = std::sqrt(dec3body.calcR2());
-  auto iBins3Body = mUtils.getBinRect(dec3body.getEta(), dec3body.getPhi(), mStrParams->mEtaBinSize, mStrParams->mPhiBinSize);
-  for (int& iBin3Body : iBins3Body) {
-    for (int iTrack{mTracksIdxTable[iBin3Body]}; iTrack < TMath::Min(mTracksIdxTable[iBin3Body + 1], int(mSortedITStracks.size())); iTrack++) {
-      strangeTrack.mMother = (o2::track::TrackParCovF)dec3body;
-      /// TODO: indices of daughters...
-      daughterTracks[kV0DauPos] = dec3body.getProng(kV0DauPos); // proton
-      daughterTracks[kV0DauNeg] = dec3body.getProng(kV0DauNeg); // pion
-      daughterTracks[kBach] = dec3body.getProng(kBach);         // deuteron
-      const auto& itsTrack = mSortedITStracks[iTrack];
-      const auto& ITSindexRef = mSortedITSindexes[iTrack];
-      if (mStrParams->mVertexMatching && (mITSvtxBrackets[ITSindexRef].getMin() > dec3bodyIdx.getVertexID() || mITSvtxBrackets[ITSindexRef].getMax() < dec3bodyIdx.getVertexID())) {
-        continue;
-      }
-      if (matchDecayToITStrack(dec3bodyR, strangeTrack, structClus, itsTrack, daughterTracks, iThread)) {
-        auto propInstance = o2::base::Propagator::Instance();
-        o2::track::TrackParCov decayVtxTrackClone = strangeTrack.mMother; // clone track and propagate to decay vertex
-        if (!propInstance->propagateToX(decayVtxTrackClone, strangeTrack.mDecayVtx[0], getBz(), o2::base::PropagatorImpl<float>::MAX_SIN_PHI, o2::base::PropagatorImpl<float>::MAX_STEP, mCorrType)) {
-          LOG(debug) << "Mother propagation to decay vertex failed";
+  if (!mStrParams->mSkip3Body) {
+    ClusAttachments structClus;
+    auto& daughterTracks = mDaughterTracks[iThread];
+    daughterTracks.resize(3); // resize to 3 prongs
+
+    StrangeTrack strangeTrack;
+    strangeTrack.mPartType = dataformats::kStrkThreeBody;
+    auto dec3bodyR = std::sqrt(dec3body.calcR2());
+    auto iBins3Body = mUtils.getBinRect(dec3body.getEta(), dec3body.getPhi(), mStrParams->mEtaBinSize, mStrParams->mPhiBinSize);
+    for (int& iBin3Body : iBins3Body) {
+      for (int iTrack{mTracksIdxTable[iBin3Body]}; iTrack < TMath::Min(mTracksIdxTable[iBin3Body + 1], int(mSortedITStracks.size())); iTrack++) {
+        strangeTrack.mMother = (o2::track::TrackParCovF)dec3body;
+        /// TODO: indices of daughters...
+        daughterTracks[kV0DauPos] = dec3body.getProng(kV0DauPos); // proton
+        daughterTracks[kV0DauNeg] = dec3body.getProng(kV0DauNeg); // pion
+        daughterTracks[kBach] = dec3body.getProng(kBach);         // deuteron
+        const auto& itsTrack = mSortedITStracks[iTrack];
+        const auto& ITSindexRef = mSortedITSindexes[iTrack];
+        if (mStrParams->mVertexMatching && (mITSvtxBrackets[ITSindexRef].getMin() > dec3bodyIdx.getVertexID() || mITSvtxBrackets[ITSindexRef].getMax() < dec3bodyIdx.getVertexID())) {
           continue;
         }
-        decayVtxTrackClone.getPxPyPzGlo(strangeTrack.mDecayMom);
-        std::array<float, 3> momPos, momNeg, momBach;
-        mFitter4Body[iThread].propagateTracksToVertex();
-        mFitter4Body[iThread].getTrack(kV0DauPos).getPxPyPzGlo(momPos);
-        mFitter4Body[iThread].getTrack(kV0DauNeg).getPxPyPzGlo(momNeg);
-        mFitter4Body[iThread].getTrack(kBach).getPxPyPzGlo(momBach);
-        /// TODO: mother mass
-        if (daughterTracks[kBach].getCharge() > 0) {
-          strangeTrack.mMasses[0] = calcMotherMass3body(momPos, momNeg, momBach, PID::Proton, PID::Pion, PID::Deuteron);
-        } else {
-          strangeTrack.mMasses[0] = calcMotherMass3body(momPos, momNeg, momBach, PID::Pion, PID::Proton, PID::Deuteron);
-        }
-
-        LOG(debug) << "ITS Track matched with a dec3body decay topology ....";
-        LOG(debug) << "Number of ITS track clusters attached: " << itsTrack.getNumberOfClusters();
-        strangeTrack.mDecayRef = i3Body;
-        strangeTrack.mITSRef = mSortedITSindexes[iTrack];
-        mStrangeTrackVec[iThread].push_back(strangeTrack);
-        mClusAttachments[iThread].push_back(structClus);
-        if (mMCTruthON) {
-          auto lab = getStrangeTrackLabel(itsTrack, strangeTrack, structClus);
-          mStrangeTrackLabels[iThread].push_back(lab);
+        if (matchDecayToITStrack(dec3bodyR, strangeTrack, structClus, itsTrack, daughterTracks, iThread)) {
+          auto propInstance = o2::base::Propagator::Instance();
+          o2::track::TrackParCov decayVtxTrackClone = strangeTrack.mMother; // clone track and propagate to decay vertex
+          if (!propInstance->propagateToX(decayVtxTrackClone, strangeTrack.mDecayVtx[0], getBz(), o2::base::PropagatorImpl<float>::MAX_SIN_PHI, o2::base::PropagatorImpl<float>::MAX_STEP, mCorrType)) {
+            LOG(debug) << "Mother propagation to decay vertex failed";
+            continue;
+          }
+          decayVtxTrackClone.getPxPyPzGlo(strangeTrack.mDecayMom);
+          std::array<float, 3> momPos, momNeg, momBach;
+          mFitter4Body[iThread].propagateTracksToVertex();
+          mFitter4Body[iThread].getTrack(kV0DauPos).getPxPyPzGlo(momPos);
+          mFitter4Body[iThread].getTrack(kV0DauNeg).getPxPyPzGlo(momNeg);
+          mFitter4Body[iThread].getTrack(kBach).getPxPyPzGlo(momBach);
+          /// TODO: mother mass
+          if (daughterTracks[kBach].getCharge() > 0) {
+            strangeTrack.mMasses[0] = calcMotherMass3body(momPos, momNeg, momBach, PID::Proton, PID::Pion, PID::Deuteron);
+          } else {
+            strangeTrack.mMasses[0] = calcMotherMass3body(momPos, momNeg, momBach, PID::Pion, PID::Proton, PID::Deuteron);
+          }
+
+          LOG(debug) << "ITS Track matched with a dec3body decay topology ....";
+          LOG(debug) << "Number of ITS track clusters attached: " << itsTrack.getNumberOfClusters();
+          strangeTrack.mDecayRef = i3Body;
+          strangeTrack.mITSRef = mSortedITSindexes[iTrack];
+          mStrangeTrackVec[iThread].push_back(strangeTrack);
+          mClusAttachments[iThread].push_back(structClus);
+          if (mMCTruthON) {
+            auto lab = getStrangeTrackLabel(itsTrack, strangeTrack, structClus);
+            mStrangeTrackLabels[iThread].push_back(lab);
+          }
         }
       }
     }
+  } else {
+    return;
   }
 }
 

Detectors/Vertexing/src/SVertexer.cxx

@@ -1182,6 +1182,11 @@ int SVertexer::check3bodyDecays(const V0Index& v0Idx, const V0& v0, float rv0, s
       m3bodyTmp[ithread].push_back(candidate3B);
     }
     m3bodyIdxTmp[ithread].emplace_back(decay3bodyVtxID, v0Idx.getProngID(0), v0Idx.getProngID(1), bach.gid);
+
+    Decay3BodyIndex decay3bodyIdx(decay3bodyVtxID, v0Idx.getProngID(0), v0Idx.getProngID(1), bach.gid);
+    if (mStrTracker) {
+      mStrTracker->process3Body(m3bodyIdxTmp[ithread].size() - 1, candidate3B, decay3bodyIdx, ithread);
+    }
   }
   return m3bodyIdxTmp[ithread].size() - n3BodyIni;
 }