[PWGCF] Add multiplicity estimator task with triplet trigger to femto framework (#17968)

Co-authored-by: ALICE Action Bot <alibuild@cern.ch>

Author: ariedel-cern

PWGCF/Femto/Core/closeTripletRejection.h

@@ -29,10 +29,13 @@ namespace o2::analysis::femto::closetripletrejection
 constexpr const char PrefixCtrTrackTrackTrack[] = "CtrTrackTrackTrack";
 constexpr const char PrefixCtrTrackTrackV0[] = "CtrTrackTrackV0";
 constexpr const char PrefixCtrTrackTrackCascade[] = "CtrTrackTrackCascade";
+constexpr const char PrefixCtrMcParticleMcParticleMcParticle[] = "CtrMcParticleMcParticleMcParticle";
 
 using ConfCtrTrackTrackTrack = closepairrejection::ConfCpr<PrefixCtrTrackTrackTrack>;
 using ConfCtrTrackTrackV0 = closepairrejection::ConfCpr<PrefixCtrTrackTrackV0>;
 using ConfCtrTrackTrackCascade = closepairrejection::ConfCpr<PrefixCtrTrackTrackCascade>;
+// generated particles, no cut by default (close triplet rejection corrects a detector effect)
+using ConfCtrMcParticleMcParticleMcParticle = closepairrejection::ConfCpr<PrefixCtrMcParticleMcParticleMcParticle, false>;
 
 // directory names
 constexpr char PrefixTrack1Track2Se[] = "CPR_Track1Track2/SE/";
@@ -42,6 +45,13 @@ constexpr char PrefixTrack1Track2Me[] = "CPR_Track1Track2/ME/";
 constexpr char PrefixTrack2Track3Me[] = "CPR_Track2Track3/ME/";
 constexpr char PrefixTrack1Track3Me[] = "CPR_Track1Track3/ME/";
 
+constexpr char PrefixMcParticle1McParticle2Se[] = "CPR_McParticle1McParticle2/SE/";
+constexpr char PrefixMcParticle2McParticle3Se[] = "CPR_McParticle2McParticle3/SE/";
+constexpr char PrefixMcParticle1McParticle3Se[] = "CPR_McParticle1McParticle3/SE/";
+constexpr char PrefixMcParticle1McParticle2Me[] = "CPR_McParticle1McParticle2/ME/";
+constexpr char PrefixMcParticle2McParticle3Me[] = "CPR_McParticle2McParticle3/ME/";
+constexpr char PrefixMcParticle1McParticle3Me[] = "CPR_McParticle1McParticle3/ME/";
+
 constexpr char PrefixTrack1V0Se[] = "CPR_Track1V0/SE/";
 constexpr char PrefixTrack2V0Se[] = "CPR_Track2V0/SE/";
 constexpr char PrefixTrack1V0Me[] = "CPR_Track1V0/ME/";
@@ -205,5 +215,40 @@ class CloseTripletRejectionTrackTrackCascade
   closepairrejection::ClosePairRejectionTrackCascade<prefixTrack2Bachelor, prefixTrack2V0Daughter> mCtrTrack2Cascade;
 };
 
+// close triplet rejection for triplets of generated particles; checks all three constituent pairs
+template <auto& prefixMcParticle1McParticle2,
+          auto& prefixMcParticle2McParticle3,
+          auto& prefixMcParticle1McParticle3>
+class CloseTripletRejectionMcParticleMcParticleMcParticle
+{
+ public:
+  CloseTripletRejectionMcParticleMcParticleMcParticle() = default;
+  ~CloseTripletRejectionMcParticleMcParticleMcParticle() = default;
+
+  template <typename T>
+  void init(o2::framework::HistogramRegistry* registry,
+            std::map<closepairrejection::CprHist, std::vector<o2::framework::AxisSpec>> const& specs,
+            T const& confCpr)
+  {
+    mCtr12.init(registry, specs, confCpr);
+    mCtr23.init(registry, specs, confCpr);
+    mCtr13.init(registry, specs, confCpr);
+  }
+
+  template <typename T1, typename T2, typename T3, typename T4>
+  [[nodiscard]] bool isCloseTriplet(T1 const& particle1, T2 const& particle2, T3 const& particle3, T4 const& tripletHistManager)
+  {
+    bool isClose12 = mCtr12.isClosePair(particle1, particle2, tripletHistManager);
+    bool isClose23 = mCtr23.isClosePair(particle2, particle3, tripletHistManager);
+    bool isClose13 = mCtr13.isClosePair(particle1, particle3, tripletHistManager);
+    return isClose12 || isClose23 || isClose13;
+  }
+
+ private:
+  closepairrejection::ClosePairRejectionMcParticleMcParticle<prefixMcParticle1McParticle2> mCtr12;
+  closepairrejection::ClosePairRejectionMcParticleMcParticle<prefixMcParticle2McParticle3> mCtr23;
+  closepairrejection::ClosePairRejectionMcParticleMcParticle<prefixMcParticle1McParticle3> mCtr13;
+};
+
 } // namespace o2::analysis::femto::closetripletrejection
 #endif // PWGCF_FEMTO_CORE_CLOSETRIPLETREJECTION_H_

PWGCF/Femto/Core/mcBuilder.h

@@ -122,9 +122,11 @@ struct ConfMcParticleSelection : o2::framework::ConfigurableGroup {
 
 constexpr const char PrefixMcParticleSelection1[] = "McParticleSelection1";
 constexpr const char PrefixMcParticleSelection2[] = "McParticleSelection2";
+constexpr const char PrefixMcParticleSelection3[] = "McParticleSelection3";
 
 using ConfMcParticleSelection1 = ConfMcParticleSelection<PrefixMcParticleSelection1>;
 using ConfMcParticleSelection2 = ConfMcParticleSelection<PrefixMcParticleSelection2>;
+using ConfMcParticleSelection3 = ConfMcParticleSelection<PrefixMcParticleSelection3>;
 
 class McBuilder
 {

PWGCF/Femto/Core/mcParticleHistManager.h

@@ -84,9 +84,11 @@ struct ConfMcParticleBinning : o2::framework::ConfigurableGroup {
 
 constexpr const char PrefixMcParticleBinning1[] = "McParticleBinning1";
 constexpr const char PrefixMcParticleBinning2[] = "McParticleBinning2";
+constexpr const char PrefixMcParticleBinning3[] = "McParticleBinning3";
 
 using ConfMcParticleBinning1 = ConfMcParticleBinning<PrefixMcParticleBinning1>;
 using ConfMcParticleBinning2 = ConfMcParticleBinning<PrefixMcParticleBinning2>;
+using ConfMcParticleBinning3 = ConfMcParticleBinning<PrefixMcParticleBinning3>;
 
 // the enum gives the correct index in the array
 constexpr std::array<histmanager::HistInfo<McParticleHist>, kMcParticleHistLast>
@@ -144,6 +146,7 @@ auto makeMcParticleHistSpecMap(const T& confBinning)
 
 inline constexpr char PrefixMcParticle1[] = "McParticle1/";
 inline constexpr char PrefixMcParticle2[] = "McParticle2/";
+inline constexpr char PrefixMcParticle3[] = "McParticle3/";
 
 constexpr std::string_view McDir = "MC/";
 

PWGCF/Femto/Core/pairHistManager.h

@@ -760,6 +760,14 @@ class PairHistManager
     mTrueMinv = getMinv(mTrueParticle1, mTrueParticle2);
     mTrueKstar = getKstar(mTrueParticle1, mTrueParticle2);
 
+    // in the pure mc-truth path there is no reco counterpart, so the generated values are also
+    // stored in the reco members; they are used by getKinematic(), i.e. by the kinematic histograms
+    // of the pair cleaner and of the close pair rejection
+    mKt = mTrueKt;
+    mMt = mTrueMt;
+    mMassInv = mTrueMinv;
+    mKstar = mTrueKstar;
+
     if (mPlotBertschPratt) {
       std::tie(mTrueQout, mTrueQside, mTrueQlong) = computeBertschPrattLCMS(mTrueParticle1, mTrueParticle2);
     }
@@ -787,6 +795,20 @@ class PairHistManager
     mTrueCent = 0.5f * (col1.cent() + col2.cent());
   }
 
+  /// pair cuts on the mc-truth values, for the pure mc-truth path (kMc without kReco),
+  /// where the reco values are never set
+  bool checkPairCutsMcTruth() const
+  {
+    return (!(mKstarMin > 0.f) || mTrueKstar > mKstarMin) &&
+           (!(mKstarMax > 0.f) || mTrueKstar < mKstarMax) &&
+           (!(mKtMin > 0.f) || mTrueKt > mKtMin) &&
+           (!(mKtMax > 0.f) || mTrueKt < mKtMax) &&
+           (!(mMtMin > 0.f) || mTrueMt > mMtMin) &&
+           (!(mMtMax > 0.f) || mTrueMt < mMtMax) &&
+           (!(mMassInvMin > 0.f) || mTrueMinv > mMassInvMin) &&
+           (!(mMassInvMax > 0.f) || mTrueMinv < mMassInvMax);
+  }
+
   bool checkPairCuts() const
   {
     return (!(mKstarMin > 0.f) || mKstar > mKstarMin) &&

PWGCF/Femto/Core/pairProcessHelpers.h

@@ -341,7 +341,7 @@ bool processSameEvent(T1 const& SliceParticle,
     if (CprManager.isClosePair(p1, p2, PairHistManager)) {
       continue;
     }
-    if (PairHistManager.checkPairCuts()) {
+    if (PairHistManager.checkPairCutsMcTruth()) {
       PairHistManager.template fill<mode>();
       PairHistManager.trackParticlesPerEvent(p1, p2);
       foundPair = true;
@@ -408,7 +408,7 @@ bool processSameEvent(T1 const& SliceParticle1,
     if (CprManager.isClosePair(p1, p2, PairHistManager)) {
       continue;
     }
-    if (PairHistManager.checkPairCuts()) {
+    if (PairHistManager.checkPairCutsMcTruth()) {
       PairHistManager.template fill<mode>();
       PairHistManager.trackParticlesPerEvent(p1, p2);
       foundPair = true;
@@ -714,7 +714,7 @@ void processMixedEvent(T1 const& Collisions,
         continue;
       }
 
-      if (PairHistManager.checkPairCuts()) {
+      if (PairHistManager.checkPairCutsMcTruth()) {
         hasValidPair = true;
         PairHistManager.trackParticlesPerEvent(p1, p2);
         PairHistManager.template fill<mode>();

PWGCF/Femto/Core/particleCleaner.h

@@ -85,8 +85,10 @@ using ConfOmegaCleaner2 = ConfParticleCleaner<PrefixOmegaCleaner2>;
 
 constexpr const char PrefixMcParticleCleaner1[] = "McParticleCleaner1";
 constexpr const char PrefixMcParticleCleaner2[] = "McParticleCleaner2";
+constexpr const char PrefixMcParticleCleaner3[] = "McParticleCleaner3";
 using ConfMcParticleCleaner1 = ConfParticleCleaner<PrefixMcParticleCleaner1>;
 using ConfMcParticleCleaner2 = ConfParticleCleaner<PrefixMcParticleCleaner2>;
+using ConfMcParticleCleaner3 = ConfParticleCleaner<PrefixMcParticleCleaner3>;
 
 class ParticleCleaner
 {