[PWGDQ] add decay length vars for MCtruth pairs to direct task

PWGDQ/Tasks/dqEfficiency_withAssoc_direct.cxx

@@ -47,6 +47,7 @@
 #include <Framework/AnalysisTask.h>
 #include <Framework/Configurable.h>
 #include <Framework/InitContext.h>
+#include <Framework/O2DatabasePDGPlugin.h>
 #include <Framework/runDataProcessing.h>
 #include <ReconstructionDataFormats/Track.h>
 
@@ -63,7 +64,7 @@
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <iterator>
 #include <map>
 #include <memory>
@@ -290,7 +291,7 @@
 void PrintBitMap(TMap map, int nbits)
 {
   for (int i = 0; i < nbits; i++) {
     cout << ((map & (TMap(1) << i)) > 0 ? "1" : "0");
   }
 }
 
@@ -325,7 +326,7 @@
 
   void init(o2::framework::InitContext& context)
   {
     cout << "AnalysisEventSelection::init() called" << endl;
     if (context.mOptions.get<bool>("processDummy")) {
       return;
     }
@@ -370,13 +371,13 @@
     fCCDB->setLocalObjectValidityChecking();
     fCCDB->setCreatedNotAfter(fConfigNoLaterThan.value);
     fCCDBApi.init(fConfigCcdbUrl.value);
     cout << "AnalysisEventSelection::init() completed" << endl;
   }
 
   template <uint32_t TEventFillMap, typename TEvents, typename TEventsMC>
   void runEventSelection(TEvents const& events, BCsWithTimestamps const& bcs, TEventsMC const& mcEvents)
   {
     cout << "AnalysisEventSelection::runEventSelection() called with " << events.size() << " events and " << bcs.size() << " BCs" << endl;
     if (bcs.size() > 0 && bcs.begin().runNumber() != fCurrentRun) {
       std::map<std::string, std::string> metadataRCT, header;
       header = fCCDBApi.retrieveHeaders(Form("RCT/Info/RunInformation/%i", bcs.begin().runNumber()), metadataRCT, -1);
@@ -385,7 +386,7 @@
       VarManager::SetSORandEOR(sor, eor);
     }
 
     cout << "Filling TimeFrame statistics histograms" << endl;
     VarManager::ResetValues(0, VarManager::kNEventWiseVariables);
     VarManager::FillTimeFrame(bcs);
     VarManager::FillTimeFrame(events);
@@ -398,7 +399,7 @@
     fBCCollMap.clear();
     // int iEvent = 0;
 
     cout << "Starting event loop for event selection" << endl;
     for (auto& event : events) {
 
       auto bc = event.template bc_as<BCsWithTimestamps>();
@@ -446,13 +447,13 @@
       }
     }
 
     cout << "AnalysisEventSelection::runEventSelection() completed" << endl;
   }
 
   template <uint32_t TEventFillMap, typename TEvents>
   void publishSelections(TEvents const& events)
   {
     cout << "AnalysisEventSelection::publishSelections() called" << endl;
     std::map<int64_t, bool> collisionSplittingMap; // key: event global index, value: whether pileup event is a possible splitting
 
     // Reset the fValues array and fill event observables
@@ -526,7 +527,7 @@
       }
       eventSel(evSel);
     }
     cout << "AnalysisEventSelection::publishSelections() completed" << endl;
   }
 
   void processDirect(MyEvents const& events, BCsWithTimestamps const& bcs, soa::Join<aod::McCollisions, aod::McCollsExtra, aod::MultMCExtras> const& mcEvents)
@@ -1151,6 +1152,8 @@
   } fConfigCCDB;
 
   Service<o2::ccdb::BasicCCDBManager> fCCDB;
+  // PDG database
+  Service<o2::framework::O2DatabasePDG> pdgDB;
 
   HistogramManager* fHistMan;
 
@@ -2076,6 +2079,16 @@
                 mcDecision |= (static_cast<uint32_t>(1) << isig);
                 VarManager::FillPairMC<TPairType>(t1_raw, t2_raw);
                 // cout << "      Filled VarManager for the pair." << endl;
+                // check if t1_raw and t2_raw have same mother to compute decay length related variables
+                if (t1_raw.has_mothers() && t2_raw.has_mothers()) {
+                  auto motherMCParticle_t1 = t1_raw.template mothers_first_as<McParticles>();
+                  auto motherMCParticle_t2 = t2_raw.template mothers_first_as<McParticles>();
+                  if (motherMCParticle_t1 == motherMCParticle_t2) {
+                    auto mcEvent = mcEvents.rawIteratorAt(motherMCParticle_t1.mcCollisionId());
+                    std::array<double, 3> collVtxPos = {mcEvent.posX(), mcEvent.posY(), mcEvent.posZ()};
+                    VarManager::FillTrackCollisionMC<TPairType>(motherMCParticle_t1, collVtxPos, pdgDB->Mass(motherMCParticle_t1.pdgCode()));
+                  }
+                }
                 if (fUseMCGenAccCut) {
                   if (!fMCGenAccCut.IsSelected(VarManager::fgValues)) {
                     continue;