[PWGCF] Add all-gap multiplicity QA to stronglyIntensiveCorr

Author: mbarlou

PWGCF/EbyEFluctuations/Tasks/stronglyIntensiveCorr.cxx

@@ -140,6 +140,16 @@ struct StronglyIntensiveCorr {
     std::vector<double> centClassEdges(centEdges.begin(), centEdges.end());
     AxisSpec centClassAxis = {centClassEdges, "centrality class (%)"};
     AxisSpec etaGapAxis = {NEtaGaps, -0.05, 1.55, "#Delta#eta"};
+
+    // Seven physical, non-overlapping FB gaps:
+    // DeltaEta = 0.0, 0.2, ..., 1.2.
+    std::vector<double> physicalGapEdges = {
+      -0.1, 0.1, 0.3, 0.5,
+      0.7, 0.9, 1.1, 1.3};
+
+    AxisSpec physicalGapAxis = {
+      physicalGapEdges,
+      "#Delta#eta"};
     AxisSpec nAxis = {500, 0.0, 500.0, "N"};
     AxisSpec counterAxis = {20, 0.5, 20.5, "counter"};
     AxisSpec ptAxis = {{0.2, 0.5, 0.8, 1.0, 1.5, 2.0, 5.0}, "#it{p}_{T} (GeV/#it{c})"};
@@ -175,6 +185,20 @@ struct StronglyIntensiveCorr {
     histos.add("QA/fb/nFminusNB", "nF-nB;nF-nB;Counts", kTH1D, {{500, -250.0, 250.0}});
     histos.add("QA/fb/nFplusNB", "nF+nB;nF+nB;Counts", kTH1D, {{500, 0.0, 500.0}});
 
+    // Event-level multiplicity QA for every physical gap.
+    // Axes: centrality x DeltaEta x multiplicity.
+    histos.add(
+      "QA/fbAllGaps/nFvsCentGap",
+      "Forward multiplicity;centrality (%);#Delta#eta;n_{F}",
+      kTH3D,
+      {centAxis, physicalGapAxis, nAxis});
+
+    histos.add(
+      "QA/fbAllGaps/nBvsCentGap",
+      "Backward multiplicity;centrality (%);#Delta#eta;n_{B}",
+      kTH3D,
+      {centAxis, physicalGapAxis, nAxis});
+
     histos.add("QA/mcReco/nRecoAll", "MC reco all selected;n;Counts", kTH1D, {nAxis});
     histos.add("QA/mcReco/nRecoPrimary", "MC reco primary selected;n;Counts", kTH1D, {nAxis});
     histos.add("QA/mcReco/nRecoSecondary", "MC reco secondary selected;n;Counts", kTH1D, {nAxis});
@@ -626,6 +650,37 @@ struct StronglyIntensiveCorr {
     histos.fill(HIST("QA/fb/nFplusNB"), nf + nb);
   }
 
+  void fillAllGapMultiplicityQA(
+    float cent,
+    std::array<double, NEtaGaps> const& nF,
+    std::array<double, NEtaGaps> const& nB)
+  {
+    for (int i = 0; i < NEtaGaps; ++i) {
+      const double gap =
+        2.0 * (etaCenter[i] -
+               cfgEtaWidth.value / 2.0);
+
+      // etaCenter = 0 corresponds to overlapping windows and
+      // gives DeltaEta = -0.2. Keep only the seven physical,
+      // non-overlapping values from 0.0 to 1.2.
+      if (gap < -1.e-6 || gap > 1.200001) {
+        continue;
+      }
+
+      histos.fill(
+        HIST("QA/fbAllGaps/nFvsCentGap"),
+        cent,
+        gap,
+        nF[i]);
+
+      histos.fill(
+        HIST("QA/fbAllGaps/nBvsCentGap"),
+        cent,
+        gap,
+        nB[i]);
+    }
+  }
+
   void fillInclusiveEtaGapMoments(std::array<double, NEtaGaps> const& nF,
                                   std::array<double, NEtaGaps> const& nB)
   {
@@ -944,6 +999,7 @@ struct StronglyIntensiveCorr {
 
     histos.fill(HIST("QA/hCentrality"), cent);
     fillFBQA(cent, nF, nB);
+    fillAllGapMultiplicityQA(cent, nF, nB);
     fillInclusiveEtaGapMoments(nF, nB);
     fillCentClassEtaGapMoments(centClass, nF, nB);
     fillCentWindowEtaGapMoments(centWindowClass, nF, nB);