PWGHF, RecoDecay: Add gen. level pT of matched D0 candidates. (#5201)

* Fix tabs.

* RecoDecay: getMother: Enforce matching type of the MC particle.

* PWGHF: MC D0: Add gen. level pT of matched candidates.

Author: vkucera

Analysis/Core/CMakeLists.txt

@@ -12,7 +12,7 @@ o2_add_library(AnalysisCore
                SOURCES  src/CorrelationContainer.cxx
                         src/TrackSelection.cxx
                         src/TriggerAliases.cxx
-			src/HFConfigurables.cxx
+                        src/HFConfigurables.cxx
                PUBLIC_LINK_LIBRARIES O2::Framework O2::AnalysisDataModel)
 
 o2_target_root_dictionary(AnalysisCore
@@ -21,7 +21,7 @@ o2_target_root_dictionary(AnalysisCore
                       include/AnalysisCore/TrackSelectionDefaults.h
                       include/AnalysisCore/TriggerAliases.h
                       include/AnalysisCore/MC.h
-		      include/AnalysisCore/HFConfigurables.h
+                      include/AnalysisCore/HFConfigurables.h
               LINKDEF src/AnalysisCoreLinkDef.h)
 
 if(FastJet_FOUND)

Analysis/Core/include/AnalysisCore/RecoDecay.h

@@ -513,8 +513,8 @@ class RecoDecay
   /// \param acceptAntiParticles  switch to accept the antiparticle of the expected mother
   /// \param sign  antiparticle indicator of the found mother w.r.t. PDGMother; 1 if particle, -1 if antiparticle, 0 if mother not found
   /// \return index of the mother particle if found, -1 otherwise
-  template <typename T, typename U>
-  static int getMother(const T& particlesMC, const U& particle, int PDGMother, bool acceptAntiParticles = false, int8_t* sign = nullptr)
+  template <typename T>
+  static int getMother(const T& particlesMC, const typename T::iterator& particle, int PDGMother, bool acceptAntiParticles = false, int8_t* sign = nullptr)
   {
     int8_t sgn = 0;                 // 1 if the expected mother is particle, -1 if antiparticle (w.r.t. PDGMother)
     int indexMother = -1;           // index of the final matched mother, if found

Analysis/Tasks/PWGHF/HFTrackIndexSkimsCreator.cxx

@@ -209,7 +209,7 @@ struct HFTrackIndexSkimsCreator {
     /*
     if (nCollsMax > -1){
       if (nColls == nCollMax){
-	return;
+        return;
         //can be added to run over limited collisions per file - for tesing purposes
       }
       nColls++;

Analysis/Tasks/PWGHF/taskD0.cxx

@@ -102,14 +102,15 @@ struct TaskD0 {
 struct TaskD0MC {
   HistogramRegistry registry{
     "registry",
-    {{"hPtRecSig", "2-prong candidates (rec. matched);#it{p}_{T} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
-     {"hPtRecBg", "2-prong candidates (rec. unmatched);#it{p}_{T} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
-     {"hPtGen", "2-prong candidates (gen. matched);#it{p}_{T} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
-     {"hCPARecSig", "2-prong candidates (rec. matched);cosine of pointing angle;entries", {HistType::kTH1F, {{110, -1.1, 1.1}}}},
-     {"hCPARecBg", "2-prong candidates (rec. unmatched);cosine of pointing angle;entries", {HistType::kTH1F, {{110, -1.1, 1.1}}}},
-     {"hEtaRecSig", "2-prong candidates (rec. matched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}},
-     {"hEtaRecBg", "2-prong candidates (rec. unmatched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}},
-     {"hEtaGen", "2-prong candidates (gen. matched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}}}};
+    {{"hPtRecSig", "2-prong candidates (matched);#it{p}_{T}^{rec.} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
+     {"hPtRecBg", "2-prong candidates (unmatched);#it{p}_{T}^{rec.} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
+     {"hPtGen", "MC particles (matched);#it{p}_{T}^{gen.} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
+     {"hPtGenSig", "2-prong candidates (matched);#it{p}_{T}^{gen.} (GeV/#it{c});entries", {HistType::kTH1F, {{100, 0., 10.}}}},
+     {"hCPARecSig", "2-prong candidates (matched);cosine of pointing angle;entries", {HistType::kTH1F, {{110, -1.1, 1.1}}}},
+     {"hCPARecBg", "2-prong candidates (unmatched);cosine of pointing angle;entries", {HistType::kTH1F, {{110, -1.1, 1.1}}}},
+     {"hEtaRecSig", "2-prong candidates (matched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}},
+     {"hEtaRecBg", "2-prong candidates (unmatched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}},
+     {"hEtaGen", "MC particles (matched);#it{#eta};entries", {HistType::kTH1F, {{100, -2., 2.}}}}}};
 
   Configurable<int> d_selectionFlagD0{"d_selectionFlagD0", 1, "Selection Flag for D0"};
   Configurable<int> d_selectionFlagD0bar{"d_selectionFlagD0bar", 1, "Selection Flag for D0bar"};
@@ -118,7 +119,7 @@ struct TaskD0MC {
   Filter filterSelectCandidates = (aod::hf_selcandidate_d0::isSelD0 >= d_selectionFlagD0 || aod::hf_selcandidate_d0::isSelD0bar >= d_selectionFlagD0bar);
 
   void process(soa::Filtered<soa::Join<aod::HfCandProng2, aod::HFSelD0Candidate, aod::HfCandProng2MCRec>> const& candidates,
-               soa::Join<aod::McParticles, aod::HfCandProng2MCGen> const& particlesMC)
+               soa::Join<aod::McParticles, aod::HfCandProng2MCGen> const& particlesMC, aod::BigTracksMC const& tracks)
   {
     // MC rec.
     //Printf("MC Candidates: %d", candidates.size());
@@ -131,7 +132,11 @@ struct TaskD0MC {
         continue;
       }
       if (std::abs(candidate.flagMCMatchRec()) == D0ToPiK) {
-        registry.fill(HIST("hPtRecSig"), candidate.pt());
+        // Get the corresponding MC particle.
+        auto indexMother = RecoDecay::getMother(particlesMC, candidate.index0_as<aod::BigTracksMC>().label_as<soa::Join<aod::McParticles, aod::HfCandProng2MCGen>>(), 421, true);
+        auto particleMother = particlesMC.iteratorAt(indexMother);
+        registry.fill(HIST("hPtGenSig"), particleMother.pt()); // gen. level pT
+        registry.fill(HIST("hPtRecSig"), candidate.pt());      // rec. level pT
         registry.fill(HIST("hCPARecSig"), candidate.cpa());
         registry.fill(HIST("hEtaRecSig"), candidate.eta());
       } else {