Add MC Reco to helicity angle analysis

Author: a-m-andrushko

PWGCF/FemtoUniverse/Tasks/femtoUniversePairTaskTrackV0Helicity.cxx

@@ -294,6 +294,14 @@ struct FemtoUniversePairTaskTrackV0Helicity {
     registryMCreco.add("minus/MCrecoPiPt", "MC reco pions;#it{p}_{T} (GeV/c)", {HistType::kTH1F, {{500, 0, 5}}});
     registryMCreco.add("minus/MCrecoPrPt", "MC reco protons;#it{p}_{T} (GeV/c)", {HistType::kTH1F, {{500, 0, 5}}});
 
+    registryMCreco.add("ThetaMCReco/hTheta", " ; p (GeV/#it{c}); cos(#theta)", kTH2F, {{100, 0, 10}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/PositiveChild/hThetaPt", " ; p_{T} (GeV/#it{c}); cos(#theta)", kTH2F, {{100, 0, 10}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/PositiveChild/hThetaEta", " ; #eta; cos(#theta)", kTH2F, {{100, -1, 1}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/PositiveChild/hThetaPhi", " ; #phi; cos(#theta)", kTH2F, {{100, -1, 7}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/NegativeChild/hThetaPt", " ; p_{T} (GeV/#it{c}); cos(#theta)", kTH2F, {{100, 0, 10}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/NegativeChild/hThetaEta", " ; #eta; cos(#theta)", kTH2F, {{100, -1, 1}, {110, -1.1, 1.1}});
+    registryMCreco.add("ThetaMCReco/NegativeChild/hThetaPhi", " ; #phi; cos(#theta)", kTH2F, {{100, -1, 7}, {110, -1.1, 1.1}});
+
     sameEventCont.init(&resultRegistry, confkstarBins, confMultBins, confkTBins, confmTBins, confMultBins3D, confmTBins3D, confEtaBins, confPhiBins, confIsMC, confUse3D);
     sameEventCont.setPDGCodes(confTrkPDGCodePartOne, confV0PDGCodePartTwo);
     mixedEventCont.init(&resultRegistry, confkstarBins, confMultBins, confkTBins, confmTBins, confMultBins3D, confmTBins3D, confEtaBins, confPhiBins, confIsMC, confUse3D);
@@ -961,6 +969,23 @@ struct FemtoUniversePairTaskTrackV0Helicity {
           }
         }
       } // partType
+
+      // Helicity angle
+      const auto& posChild = parts.iteratorAt(part.index() - 2);
+      const auto& negChild = parts.iteratorAt(part.index() - 1);
+
+      auto posChildMass = pdg->Mass(confPDGCodePosChild);
+      auto negChildMass = pdg->Mass(confPDGCodeNegChild);
+      auto posChildBoosted = FemtoUniverseMath::boostPRF<decltype(posChild)>(posChild, posChildMass, negChild, negChildMass);
+      auto cosineTheta = (posChildBoosted.Px() * part.px() + posChildBoosted.Py() * part.py() + posChildBoosted.Pz() * part.pz()) / (posChildBoosted.P() * part.p());
+
+      registryMCreco.fill(HIST("ThetaMCReco/hTheta"), part.p(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/PositiveChild/hThetaPt"), posChild.pt(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/PositiveChild/hThetaEta"), posChild.eta(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/PositiveChild/hThetaPhi"), posChild.phi(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/NegativeChild/hThetaPt"), negChild.pt(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/NegativeChild/hThetaEta"), negChild.eta(), cosineTheta);
+      registryMCreco.fill(HIST("ThetaMCReco/NegativeChild/hThetaPhi"), negChild.phi(), cosineTheta);
     }
   }