[PWGHF] Add UPC process function and QA hists to taskD0

This commit adds support for analyzing Ultra-Peripheral Collisions (UPC)
in the D0 → K- π+ analysis, following the implementation in taskLc and taskDplus.

Changes include:
- Added UPC-related library dependencies in CMakeLists.txt
- Added CCDB manager and UPC helper includes
- Implemented GapType enum for gap classification
- Added QA histograms for FT0 and ZDC detectors
- Implemented determineGapType() function for event classification
- Added runAnalysisPerCollisionDataWithUpc() template function
- Added processDataWithDCAFitterNMlWithUpc() process function
- Added candD0PerCollision Preslice for efficient candidate slicing

The UPC analysis uses FT0 and ZDC detector information to classify
events into Gap A, Gap C, or Double Gap categories based on detector
thresholds, enabling studies of diffractive processes in D0 production.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: minjungkim12

PWGHF/D2H/Tasks/CMakeLists.txt

@@ -71,7 +71,7 @@ o2physics_add_dpl_workflow(task-charm-reso-to-d-trk-reduced
 
 o2physics_add_dpl_workflow(task-d0
                     SOURCES taskD0.cxx
-                    PUBLIC_LINK_LIBRARIES O2Physics::AnalysisCore O2Physics::AnalysisCCDB
+                    PUBLIC_LINK_LIBRARIES O2Physics::AnalysisCore O2Physics::AnalysisCCDB O2Physics::SGCutParHolder O2Physics::EventFilteringUtils
                     COMPONENT_NAME Analysis)
 
 o2physics_add_dpl_workflow(task-directed-flow-charm-hadrons

PWGHF/D2H/Tasks/taskD0.cxx

@@ -14,6 +14,7 @@
 ///
 /// \author Gian Michele Innocenti <gian.michele.innocenti@cern.ch>, CERN
 /// \author Vít Kučera <vit.kucera@cern.ch>, CERN
+/// \author Minjung Kim <minjung.kim@cern.ch>, CERN 
 
 #include "PWGHF/Core/CentralityEstimation.h"
 #include "PWGHF/Core/DecayChannels.h"
@@ -22,6 +23,7 @@
 #include "PWGHF/DataModel/CandidateReconstructionTables.h"
 #include "PWGHF/DataModel/CandidateSelectionTables.h"
 #include "PWGHF/Utils/utilsEvSelHf.h"
+#include "PWGUD/Core/UPCHelpers.h"
 
 #include "Common/CCDB/ctpRateFetcher.h"
 #include "Common/Core/RecoDecay.h"
@@ -56,6 +58,13 @@ using namespace o2::framework;
 using namespace o2::framework::expressions;
 using namespace o2::hf_centrality;
 using namespace o2::hf_occupancy;
+using namespace o2::hf_evsel;
+
+enum class GapType {
+  GapA = 0,
+  GapC = 1,
+  DoubleGap = 2,
+};
 
 /// D0 analysis task
 namespace
@@ -87,8 +96,12 @@ struct HfTaskD0 {
   // ML inference
   Configurable<bool> applyMl{"applyMl", false, "Flag to apply ML selections"};
   Configurable<std::string> ccdbUrl{"ccdbUrl", "http://alice-ccdb.cern.ch", "url of the ccdb repository"};
+  Configurable<std::string> ccdbPathGrp{"ccdbPathGrp", "GLO/GRP/GRP", "Path of the grp file (Run 2)"};
+  Configurable<std::string> ccdbPathGrpMag{"ccdbPathGrpMag", "GLO/Config/GRPMagField", "CCDB path of the GRPMagField object (Run 3)"};
   Configurable<std::string> irSource{"irSource", "ZNC hadronic", "Estimator of the interaction rate (Recommended: pp --> T0VTX, Pb-Pb --> ZNC hadronic)"};
 
+  HfEventSelection hfEvSel; // event selection and monitoring
+
   HfHelper hfHelper;
   ctpRateFetcher mRateFetcher;
 
@@ -110,6 +123,8 @@ struct HfTaskD0 {
   using CollisionsWithMcLabels = soa::Join<aod::Collisions, aod::McCollisionLabels, aod::EvSels>;
   using CollisionsWithMcLabelsCent = soa::Join<aod::Collisions, aod::McCollisionLabels, aod::EvSels, aod::CentFT0Ms, aod::CentFT0Cs>;
   using TracksSelQuality = soa::Join<aod::TracksExtra, aod::TracksWMc>;
+
+  Preslice<aod::HfCand2Prong> candD0PerCollision = aod::hf_cand::collisionId;
   PresliceUnsorted<CollisionsWithMcLabels> colPerMcCollision = aod::mccollisionlabel::mcCollisionId;
   PresliceUnsorted<CollisionsWithMcLabelsCent> colPerMcCollisionCent = aod::mccollisionlabel::mcCollisionId;
 
@@ -218,9 +233,11 @@ struct HfTaskD0 {
      {"hMassReflBkgD0bar", "2-prong candidates (matched);#it{m}_{inv} (GeV/#it{c}^{2}); #it{p}_{T}; #it{y}", {HistType::kTH3F, {{120, 1.5848, 2.1848}, {150, 0., 30.}, {20, -5., 5.}}}},
      {"hMassSigBkgD0bar", "2-prong candidates (not checked);#it{m}_{inv} (GeV/#it{c}^{2}); #it{p}_{T}; #it{y}", {HistType::kTH3F, {{120, 1.5848, 2.1848}, {150, 0., 30.}, {20, -5., 5.}}}}}};
 
+  HistogramRegistry qaRegistry{"QAHistos", {}, OutputObjHandlingPolicy::AnalysisObject};
+
   void init(InitContext&)
   {
-    std::array<bool, 12> doprocess{doprocessDataWithDCAFitterN, doprocessDataWithDCAFitterNCent, doprocessDataWithKFParticle, doprocessMcWithDCAFitterN, doprocessMcWithDCAFitterNCent, doprocessMcWithKFParticle, doprocessDataWithDCAFitterNMl, doprocessDataWithDCAFitterNMlCent, doprocessDataWithKFParticleMl, doprocessMcWithDCAFitterNMl, doprocessMcWithDCAFitterNMlCent, doprocessMcWithKFParticleMl};
+    std::array<bool, 13> doprocess{doprocessDataWithDCAFitterN, doprocessDataWithDCAFitterNCent, doprocessDataWithKFParticle, doprocessMcWithDCAFitterN, doprocessMcWithDCAFitterNCent, doprocessMcWithKFParticle, doprocessDataWithDCAFitterNMl, doprocessDataWithDCAFitterNMlCent, doprocessDataWithKFParticleMl, doprocessMcWithDCAFitterNMl, doprocessMcWithDCAFitterNMlCent, doprocessMcWithKFParticleMl, doprocessDataWithDCAFitterNMlWithUpc};
     if ((std::accumulate(doprocess.begin(), doprocess.end(), 0)) == 0) {
       LOGP(fatal, "At least one process function should be enabled at a time.");
     }
@@ -332,6 +349,15 @@ struct HfTaskD0 {
       registry.get<THnSparse>(HIST("hMassVsPtVsPtBVsYVsOriginVsD0Type"))->Sumw2();
     }
 
+    qaRegistry.add("Data/fitInfo/ampFT0A_vs_ampFT0C", "FT0-A vs FT0-C amplitude;FT0-A amplitude (a.u.);FT0-C amplitude (a.u.)", {HistType::kTH2F, {{2500, 0., 250}, {2500, 0., 250}}});
+    qaRegistry.add("Data/zdc/energyZNA_vs_energyZNC", "ZNA vs ZNC common energy;E_{ZNA}^{common} (a.u.);E_{ZNC}^{common} (a.u.)", {HistType::kTH2F, {{200, 0., 20}, {200, 0., 20}}});
+    qaRegistry.add("Data/hUpcGapAfterSelection", "UPC gap type after selection;Gap side;Counts", {HistType::kTH1F, {{3, -0.5, 2.5}}});
+    qaRegistry.get<TH1>(HIST("Data/hUpcGapAfterSelection"))->GetXaxis()->SetBinLabel(static_cast<int>(GapType::GapA) + 1, "A");
+    qaRegistry.get<TH1>(HIST("Data/hUpcGapAfterSelection"))->GetXaxis()->SetBinLabel(static_cast<int>(GapType::GapC) + 1, "C");
+    qaRegistry.get<TH1>(HIST("Data/hUpcGapAfterSelection"))->GetXaxis()->SetBinLabel(static_cast<int>(GapType::DoubleGap) + 1, "Double");
+
+    hfEvSel.addHistograms(qaRegistry);
+
     ccdb->setURL(ccdbUrl);
     ccdb->setCaching(true);
     ccdb->setLocalObjectValidityChecking();
@@ -516,6 +542,99 @@ struct HfTaskD0 {
       }
     }
   }
+
+  GapType determineGapType(float FT0A, float FT0C, float ZNA, float ZNC)
+  {
+    constexpr float FT0AThreshold = 100.0;
+    constexpr float FT0CThreshold = 50.0;
+    constexpr float ZDCThreshold = 1.0;
+    if (FT0A < FT0AThreshold && FT0C > FT0CThreshold && ZNA < ZDCThreshold && ZNC > ZDCThreshold) {
+      return GapType::GapA;
+    }
+    if (FT0A > FT0AThreshold && FT0C < FT0CThreshold && ZNA > ZDCThreshold && ZNC < ZDCThreshold) {
+      return GapType::GapC;
+    }
+    return GapType::DoubleGap;
+  }
+
+  template <bool fillMl, typename CollType, typename CandType, typename BCsType>
+  void runAnalysisPerCollisionDataWithUpc(CollType const& collisions,
+                                          CandType const& candidates,
+                                          BCsType const& bcs,
+                                          aod::FT0s const& ft0s,
+                                          aod::FV0As const& fv0as,
+                                          aod::FDDs const& fdds)
+  {
+    for (const auto& collision : collisions) {
+      uint32_t rejectionMask{0};
+      float centrality{-1.f};
+      rejectionMask = hfEvSel.getHfCollisionRejectionMaskWithUpc<true, CentralityEstimator::None, BCsType>(collision, centrality, ccdb, qaRegistry, bcs);
+      if (rejectionMask != 0) {
+        continue;
+      }
+      auto bc = collision.template bc_as<BCsType>();
+      upchelpers::FITInfo fitInfo{};
+      udhelpers::getFITinfo(fitInfo, bc, bcs, ft0s, fv0as, fdds);
+
+      GapType gap = GapType::DoubleGap;
+      if (bc.has_zdc()) {
+        auto zdc = bc.zdc();
+        qaRegistry.fill(HIST("Data/fitInfo/ampFT0A_vs_ampFT0C"), fitInfo.ampFT0A, fitInfo.ampFT0C);
+        qaRegistry.fill(HIST("Data/zdc/energyZNA_vs_energyZNC"), zdc.energyCommonZNA(), zdc.energyCommonZNC());
+        gap = determineGapType(fitInfo.ampFT0A, fitInfo.ampFT0C, zdc.energyCommonZNA(), zdc.energyCommonZNC());
+        qaRegistry.fill(HIST("Data/hUpcGapAfterSelection"), static_cast<int>(gap));
+      }
+      if (gap == GapType::GapA || gap == GapType::GapC) {
+        const auto thisCollId = collision.globalIndex();
+        const auto& groupedD0Candidates = candidates.sliceBy(candD0PerCollision, thisCollId);
+
+        for (const auto& candidate : groupedD0Candidates) {
+          if (!(candidate.hfflag() & 1 << aod::hf_cand_2prong::DecayType::D0ToPiK)) {
+            continue;
+          }
+          if (yCandRecoMax >= 0. && std::abs(hfHelper.yD0(candidate)) > yCandRecoMax) {
+            continue;
+          }
+
+          float massD0 = hfHelper.invMassD0ToPiK(candidate);
+          float massD0bar = hfHelper.invMassD0barToKPi(candidate);
+          auto ptCandidate = candidate.pt();
+
+          if (candidate.isSelD0() >= selectionFlagD0) {
+            registry.fill(HIST("hMass"), massD0, ptCandidate);
+            registry.fill(HIST("hMassFinerBinning"), massD0, ptCandidate);
+            registry.fill(HIST("hMassVsPhi"), massD0, ptCandidate, candidate.phi());
+          }
+          if (candidate.isSelD0bar() >= selectionFlagD0bar) {
+            registry.fill(HIST("hMass"), massD0bar, ptCandidate);
+            registry.fill(HIST("hMassFinerBinning"), massD0bar, ptCandidate);
+            registry.fill(HIST("hMassVsPhi"), massD0bar, ptCandidate, candidate.phi());
+          }
+
+          if constexpr (fillMl) {
+            if (candidate.isSelD0() >= selectionFlagD0) {
+              registry.fill(HIST("hBdtScoreVsMassVsPtVsPtBVsYVsOriginVsD0Type"), candidate.mlProbD0()[0], candidate.mlProbD0()[1], candidate.mlProbD0()[2], massD0, ptCandidate, hfHelper.yD0(candidate), SigD0);
+              registry.fill(HIST("hBdtScoreVsMassVsPtVsPtBVsYVsOriginVsD0Type"), candidate.mlProbD0()[0], candidate.mlProbD0()[1], candidate.mlProbD0()[2], massD0, ptCandidate, hfHelper.yD0(candidate), candidate.isSelD0bar() ? ReflectedD0 : PureSigD0);
+            }
+            if (candidate.isSelD0bar() >= selectionFlagD0bar) {
+              registry.fill(HIST("hBdtScoreVsMassVsPtVsPtBVsYVsOriginVsD0Type"), candidate.mlProbD0()[0], candidate.mlProbD0()[1], candidate.mlProbD0()[2], massD0bar, ptCandidate, hfHelper.yD0(candidate), SigD0bar);
+              registry.fill(HIST("hBdtScoreVsMassVsPtVsPtBVsYVsOriginVsD0Type"), candidate.mlProbD0()[0], candidate.mlProbD0()[1], candidate.mlProbD0()[2], massD0bar, ptCandidate, hfHelper.yD0(candidate), candidate.isSelD0() ? ReflectedD0bar : PureSigD0bar);
+            }
+          } else {
+            if (candidate.isSelD0() >= selectionFlagD0) {
+              registry.fill(HIST("hMassVsPtVsPtBVsYVsOriginVsD0Type"), massD0, ptCandidate, hfHelper.yD0(candidate), SigD0);
+              registry.fill(HIST("hMassVsPtVsPtBVsYVsOriginVsD0Type"), massD0, ptCandidate, hfHelper.yD0(candidate), candidate.isSelD0bar() ? ReflectedD0 : PureSigD0);
+            }
+            if (candidate.isSelD0bar() >= selectionFlagD0bar) {
+              registry.fill(HIST("hMassVsPtVsPtBVsYVsOriginVsD0Type"), massD0bar, ptCandidate, hfHelper.yD0(candidate), SigD0bar);
+              registry.fill(HIST("hMassVsPtVsPtBVsYVsOriginVsD0Type"), massD0bar, ptCandidate, hfHelper.yD0(candidate), candidate.isSelD0() ? ReflectedD0bar : PureSigD0bar);
+            }
+          }
+        }
+      }
+    }
+  }
+
   void processDataWithDCAFitterN(D0Candidates const&, Collisions const& collisions, aod::TracksWExtra const& tracks, aod::BcFullInfos const& bcs)
   {
     processData<aod::hf_cand::VertexerType::DCAFitter, false>(selectedD0Candidates, collisions, tracks, bcs);
@@ -977,6 +1096,19 @@ struct HfTaskD0 {
   }
   PROCESS_SWITCH(HfTaskD0, processMcWithKFParticleMl, "Process MC with KFParticle and ML selections", false);
   // TODO: add the processMcWithKFParticleMlCent
+
+  void processDataWithDCAFitterNMlWithUpc(soa::Join<aod::Collisions, aod::EvSels> const& collisions,
+                                          aod::BcFullInfos const& bcs,
+                                          D0CandidatesMl const&,
+                                          aod::TracksWExtra const& tracks,
+                                          aod::FT0s const& ft0s,
+                                          aod::FV0As const& fv0as,
+                                          aod::FDDs const& fdds,
+                                          aod::Zdcs const& /*zdcs*/)
+  {
+    runAnalysisPerCollisionDataWithUpc<true>(collisions, selectedD0CandidatesMl, bcs, ft0s, fv0as, fdds);
+  }
+  PROCESS_SWITCH(HfTaskD0, processDataWithDCAFitterNMlWithUpc, "Process real data with DCAFitterN and ML with UPC", false);
 };
 
 WorkflowSpec defineDataProcessing(ConfigContext const& cfgc)