PWGLF: optional proper lifetime at builder time, def off (AliceO2Grou…

…p#4499) * PWGLF: optional proper lifetime at builder time, def off * Please consider the following formatting changes (#228) * Update strangederivedbuilder.cxx --------- Co-authored-by: ALICE Builder <[email protected]>
ddobrigk · Jan 29, 2024 · 2dc8ebc · 2dc8ebc
1 parent bd36cbc
commit 2dc8ebc
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Showing 2 changed files with 45 additions and 16 deletions.
diff --git a/PWGLF/TableProducer/lambdakzerobuilder.cxx b/PWGLF/TableProducer/lambdakzerobuilder.cxx
@@ -194,6 +194,13 @@ struct lambdakzeroBuilder {
   Configurable<bool> massWindowWithTPCPID{"massWindowWithTPCPID", true, "when checking mass windows, correlate with TPC dE/dx"};
   Configurable<float> massWindowSafetyMargin{"massWindowSafetyMargin", 0.001, "Extra mass window safety margin"};
 
+  // apply lifetime cuts to K0Short and Lambda candidates
+  // unit of measurement: centimeters
+  // lifetime of Lambda ~7.9cm but keep in mind feeddown from cascades
+  // lifetime of K0Short ~2.5cm, no feeddown and plenty to cut
+  static constexpr float defaultLifetimeCuts[1][2] = {{1e+6, 1e+6}};
+  Configurable<LabeledArray<float>> lifetimecut{"lifetimecut", {defaultLifetimeCuts[0], 2, {"lifetimecutLambda", "lifetimecutK0S"}}, "lifetimecut"};
+
   int mRunNumber;
   float d_bz;
   float maxSnp;  // max sine phi for propagation
@@ -717,6 +724,8 @@ struct lambdakzeroBuilder {
     auto py = v0candidate.posP[1] + v0candidate.negP[1];
     auto pz = v0candidate.posP[2] + v0candidate.negP[2];
     auto lPt = RecoDecay::sqrtSumOfSquares(v0candidate.posP[0] + v0candidate.negP[0], v0candidate.posP[1] + v0candidate.negP[1]);
+    auto lPtotal = RecoDecay::sqrtSumOfSquares(lPt, v0candidate.posP[2] + v0candidate.negP[2]);
+    auto lLengthTraveled = RecoDecay::sqrtSumOfSquares(v0candidate.pos[0] - primaryVertex.getX(), v0candidate.pos[1] - primaryVertex.getY(), v0candidate.pos[2] - primaryVertex.getZ());
 
     // Momentum range check
     if (lPt < minimumPt || lPt > maximumPt) {
@@ -729,6 +738,11 @@ struct lambdakzeroBuilder {
       return false; // reject - daughters have too large eta to be reliable for MC corrections
     }
 
+    // calculate proper lifetime
+    // m*L/p for each hypothesis
+    float lML2P_K0Short = o2::constants::physics::MassKaonNeutral * lLengthTraveled / lPtotal;
+    float lML2P_Lambda = o2::constants::physics::MassLambda * lLengthTraveled / lPtotal;
+
     // Passes momentum window check
     statisticsRegistry.v0stats[kWithinMomentumRange]++;
 
@@ -741,25 +755,40 @@ struct lambdakzeroBuilder {
     auto lAntiHypertritonMass = RecoDecay::m(array{array{v0candidate.posP[0], v0candidate.posP[1], v0candidate.posP[2]}, array{2.0f * v0candidate.negP[0], 2.0f * v0candidate.negP[1], 2.0f * v0candidate.negP[2]}}, array{o2::constants::physics::MassPionCharged, o2::constants::physics::MassHelium3});
 
     // mass window check
-    bool desiredMass = false;
+    bool keepCandidate = false;
+
+    bool desiredMassK0Short = false;
+    bool desiredMassLambda = false;
+    bool desiredMassAntiLambda = false;
+
     if (massWindownumberOfSigmas > 1e+3) {
-      desiredMass = true; // safety fallback
+      desiredMassK0Short = true;    // safety fallback
+      desiredMassLambda = true;     // safety fallback
+      desiredMassAntiLambda = true; // safety fallback
     } else {
-      // check if user requested to correlate mass requirement with TPC PID
-      // (useful for data volume reduction)
-      bool dEdxK0Short = V0.isdEdxK0Short() || !massWindowWithTPCPID;
-      bool dEdxLambda = V0.isdEdxLambda() || !massWindowWithTPCPID;
-      bool dEdxAntiLambda = V0.isdEdxAntiLambda() || !massWindowWithTPCPID;
-
-      if (dEdxK0Short && TMath::Abs(v0candidate.k0ShortMass - o2::constants::physics::MassKaonNeutral) < massWindownumberOfSigmas * getMassSigmaK0Short(lPt) + massWindowSafetyMargin)
-        desiredMass = true;
-      if (dEdxLambda && TMath::Abs(v0candidate.lambdaMass - o2::constants::physics::MassLambda) < massWindownumberOfSigmas * getMassSigmaLambda(lPt) + massWindowSafetyMargin)
-        desiredMass = true;
-      if (dEdxAntiLambda && TMath::Abs(v0candidate.antiLambdaMass - o2::constants::physics::MassLambda) < massWindownumberOfSigmas * getMassSigmaLambda(lPt) + massWindowSafetyMargin)
-        desiredMass = true;
+      desiredMassK0Short = TMath::Abs(v0candidate.k0ShortMass - o2::constants::physics::MassKaonNeutral) < massWindownumberOfSigmas * getMassSigmaK0Short(lPt) + massWindowSafetyMargin;
+      desiredMassLambda = TMath::Abs(v0candidate.lambdaMass - o2::constants::physics::MassLambda) < massWindownumberOfSigmas * getMassSigmaLambda(lPt) + massWindowSafetyMargin;
+      desiredMassAntiLambda = TMath::Abs(v0candidate.antiLambdaMass - o2::constants::physics::MassLambda) < massWindownumberOfSigmas * getMassSigmaLambda(lPt) + massWindowSafetyMargin;
     }
 
-    if (!desiredMass)
+    // check if user requested to correlate mass requirement with TPC PID
+    // (useful for data volume reduction)
+    bool dEdxK0Short = V0.isdEdxK0Short() || !massWindowWithTPCPID;
+    bool dEdxLambda = V0.isdEdxLambda() || !massWindowWithTPCPID;
+    bool dEdxAntiLambda = V0.isdEdxAntiLambda() || !massWindowWithTPCPID;
+
+    // check proper lifetime if asked for
+    bool passML2P_K0Short = lML2P_K0Short < lifetimecut->get("lifetimecutK0S") || lifetimecut->get("lifetimecutK0S") > 1000;
+    bool passML2P_Lambda = lML2P_Lambda < lifetimecut->get("lifetimecutLambda") || lifetimecut->get("lifetimecutLambda") > 1000;
+
+    if (passML2P_K0Short && dEdxK0Short && desiredMassK0Short)
+      keepCandidate = true;
+    if (passML2P_Lambda && dEdxLambda && desiredMassLambda)
+      keepCandidate = true;
+    if (passML2P_Lambda && dEdxAntiLambda && desiredMassAntiLambda)
+      keepCandidate = true;
+
+    if (!keepCandidate)
       return false;
 
     if (d_doTrackQA) {

diff --git a/PWGLF/TableProducer/strangederivedbuilder.cxx b/PWGLF/TableProducer/strangederivedbuilder.cxx
@@ -503,7 +503,7 @@ struct strangederivedbuilder {
     histos.fill(HIST("h2dNVerticesVsCentrality"), bestCentrality, collisions.size());
 
     for (auto& mcp : mcParticles) {
-      if (TMath::Abs(mcp.y()) < 0.5) {
+      if (TMath::Abs(mcp.y()) < 0.5 && mcp.isPhysicalPrimary()) {
         static_for<0, nSpecies - 1>([&](auto i) {
           constexpr int index = i.value;
           if (mcp.pdgCode() == particlePDGCodes[index] && bitcheck(enabledBits, index)) {