[PWGDQ] Add e-mu pairing with MC matching to dqEfficiency_withAssoc (#16276)

Author: Shunsuke-Kurita

PWGDQ/Core/HistogramsLibrary.cxx

@@ -1971,6 +1971,15 @@ void o2::aod::dqhistograms::DefineHistograms(HistogramManager* hm, const char* h
     if (subGroupStr.Contains("correlation-emu")) {
       hm->AddHistogram(histClass, "DeltaPhiPair2_DeltaEtaPair2", "", false, 600, -o2::constants::math::PIHalf, 1.5 * o2::constants::math::PI, VarManager::kDeltaPhiPair2, 350, 1.5, 5.0, VarManager::kDeltaEtaPair2);
       hm->AddHistogram(histClass, "DeltaPhiPair2_Pt", "", false, 600, -o2::constants::math::PIHalf, 1.5 * o2::constants::math::PI, VarManager::kDeltaPhiPair2, 200, 0.0, 20.0, VarManager::kPt);
+      // 4D correlation map: (Delta phi_pair, Delta eta_pair, p_T^{e}, p_T^{mu}). Per-track pT axes use kPt1/kPt2,
+      // which FillPair populates for SE and FillPairME (patched in this PR) populates for ME. Stored as THnSparse so
+      // running with many MC-matched hist classes (track cut x muon cut x signal x QA variant) does not blow the
+      // 1 GB TBufferFile limit during the final ROOT serialization.
+      int varsEmu4D[4] = {VarManager::kDeltaPhiPair2, VarManager::kDeltaEtaPair2, VarManager::kPt1, VarManager::kPt2};
+      int binsEmu4D[4] = {60, 35, 20, 20};
+      double xminEmu4D[4] = {-o2::constants::math::PIHalf, 1.5, 0.0, 0.0};
+      double xmaxEmu4D[4] = {1.5 * o2::constants::math::PI, 5.0, 20.0, 20.0};
+      hm->AddHistogram(histClass, "DeltaPhiPair2_DeltaEtaPair2_PtE_PtMu", "", 4, varsEmu4D, binsEmu4D, xminEmu4D, xmaxEmu4D, nullptr, -1, kTRUE);
     }
     if (subGroupStr.Contains("dielectrons")) {
       if (subGroupStr.Contains("prefilter")) {

PWGDQ/Core/MCSignalLibrary.cxx

@@ -459,6 +459,30 @@ MCSignal* o2::aod::dqmcsignals::GetMCSignal(const char* name)
     signal = new MCSignal(name, "Electron-muon pair", {electron, muon}, {-1, -1});
     return signal;
   }
+  if (!nameStr.compare("emuFromOpenHFhadron")) {
+    MCProng electron(2, {11, 902}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    electron.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    MCProng muon(2, {13, 902}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    muon.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    signal = new MCSignal(name, "e and mu each from an open charm or beauty hadron decay", {electron, muon}, {-1, -1});
+    return signal;
+  }
+  if (!nameStr.compare("emuFromOpenCharmHadron")) {
+    MCProng electron(2, {11, 402}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    electron.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    MCProng muon(2, {13, 402}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    muon.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    signal = new MCSignal(name, "e and mu each from an open charm hadron decay", {electron, muon}, {-1, -1});
+    return signal;
+  }
+  if (!nameStr.compare("emuFromOpenBeautyHadron")) {
+    MCProng electron(2, {11, 502}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    electron.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    MCProng muon(2, {13, 502}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
+    muon.SetSourceBit(0, MCProng::kPhysicalPrimary);
+    signal = new MCSignal(name, "e and mu each from an open beauty hadron decay", {electron, muon}, {-1, -1});
+    return signal;
+  }
   if (!nameStr.compare("dielectronFromPC")) {
     MCProng prong(2, {11, 22}, {true, true}, {false, false}, {0, 0}, {0, 0}, {false, false});
     signal = new MCSignal(name, "dielectron from a photon conversion", {prong, prong}, {1, 1});

PWGDQ/Core/VarManager.h

@@ -3998,6 +3998,14 @@ void VarManager::FillPairME(T1 const& t1, T2 const& t2, float* values)
   values[kPhi] = v12.Phi() > 0 ? v12.Phi() : v12.Phi() + 2. * M_PI;
   values[kRap] = -v12.Rapidity();
 
+  // Per-track quantities so ME histograms can use kPt1/kPt2/kEta1/kEta2/kPhi1/kPhi2 just like SE FillPair does.
+  values[kPt1] = t1.pt();
+  values[kEta1] = t1.eta();
+  values[kPhi1] = t1.phi();
+  values[kPt2] = t2.pt();
+  values[kEta2] = t2.eta();
+  values[kPhi2] = t2.phi();
+
   if (fgUsedVars[kDeltaPhiPair2]) {
     double phipair2ME = v1.Phi() - v2.Phi();
     if (phipair2ME > 3 * TMath::Pi() / 2) {