Add additional selections on ITS tracks (#13779)

Author: mpuccio

Detectors/ITSMFT/ITS/tracking/include/ITStracking/Configuration.h

@@ -94,6 +94,8 @@ struct TrackingParameters {
   unsigned long MaxMemory = 12000000000UL;
   float MaxChi2ClusterAttachment = 60.f;
   float MaxChi2NDF = 30.f;
+  float MinPt = 0.f;
+  unsigned char StartLayerMask = 0x7F;
   bool FindShortTracks = false;
   bool PerPrimaryVertexProcessing = false;
   bool SaveTimeBenchmarks = false;

Detectors/ITSMFT/ITS/tracking/src/TrackerTraits.cxx

@@ -573,6 +573,9 @@ void TrackerTraits::findRoads(const int iteration)
     const int minimumLayer{startLevel - 1};
     std::vector<CellSeed> trackSeeds;
     for (int startLayer{mTrkParams[iteration].CellsPerRoad() - 1}; startLayer >= minimumLayer; --startLayer) {
+      if ((mTrkParams[iteration].StartLayerMask & (1 << (startLayer + 2))) == 0) {
+        continue;
+      }
       CA_DEBUGGER(std::cout << "\t\t > Starting processing layer " << startLayer << std::endl);
       std::vector<int> lastCellId, updatedCellId;
       std::vector<CellSeed> lastCellSeed, updatedCellSeed;
@@ -615,7 +618,7 @@ void TrackerTraits::findRoads(const int iteration)
       temporaryTrack.resetCovariance();
       temporaryTrack.setChi2(0);
       fitSuccess = fitTrack(temporaryTrack, mTrkParams[0].NLayers - 1, -1, -1, mTrkParams[0].MaxChi2ClusterAttachment, mTrkParams[0].MaxChi2NDF, 50.f);
-      if (!fitSuccess) {
+      if (!fitSuccess || temporaryTrack.getPt() < mTrkParams[iteration].MinPt) {
         continue;
       }
       tracks[trackIndex++] = temporaryTrack;

Detectors/ITSMFT/ITS/tracking/src/TrackingInterface.cxx

@@ -47,6 +47,8 @@ void ITSTrackingInterface::initialise()
     trackParams[2].TrackletMinPt = 0.1f;
     trackParams[2].CellDeltaTanLambdaSigma *= 4.;
     trackParams[2].MinTrackLength = 4;
+    trackParams[2].MinPt = 0.2f;
+    trackParams[2].StartLayerMask = (1 << 6) + (1 << 3);
     if (o2::its::TrackerParamConfig::Instance().doUPCIteration) {
       trackParams[3].TrackletMinPt = 0.1f;
       trackParams[3].CellDeltaTanLambdaSigma *= 4.;