From ecb377db491e6eacb446aff22a0d45d8536b74ab Mon Sep 17 00:00:00 2001
From: Luzhiyongg <71517277+Luzhiyongg@users.noreply.github.com>
Date: Mon, 25 Aug 2025 16:51:18 +0200
Subject: [PATCH] add TPCsectorOverlap check on request

---
 PWGCF/Flow/Tasks/flowTask.cxx | 59 +++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/PWGCF/Flow/Tasks/flowTask.cxx b/PWGCF/Flow/Tasks/flowTask.cxx
index 9f27ffa0005..a7691188f19 100644
--- a/PWGCF/Flow/Tasks/flowTask.cxx
+++ b/PWGCF/Flow/Tasks/flowTask.cxx
@@ -36,6 +36,7 @@
 #include "Framework/RunningWorkflowInfo.h"
 #include "Framework/runDataProcessing.h"
 #include <CCDB/BasicCCDBManager.h>
+#include <DataFormatsParameters/GRPMagField.h>
 
 #include "TList.h"
 #include <TF1.h>
@@ -141,6 +142,13 @@ struct FlowTask {
     TF1* fMultMultV0ACutHigh = nullptr;
     TF1* fT0AV0AMean = nullptr;
     TF1* fT0AV0ASigma = nullptr;
+    // for TPC sector boundary
+    O2_DEFINE_CONFIGURABLE(cfgShowTPCsectorOverlap, bool, true, "Draw TPC sector overlap")
+    O2_DEFINE_CONFIGURABLE(cfgRejectionTPCsectorOverlap, bool, false, "rejection for TPC sector overlap")
+    O2_DEFINE_CONFIGURABLE(cfgMagnetField, std::string, "GLO/Config/GRPMagField", "CCDB path to Magnet field object")
+    ConfigurableAxis axisPhiMod{"axisPhiMod", {100, 0, constants::math::PI / 9}, "fmod(#varphi,#pi/9)"};
+    TF1* fPhiCutLow = nullptr;
+    TF1* fPhiCutHigh = nullptr;
   } cfgFuncParas;
 
   ConfigurableAxis axisPtHist{"axisPtHist", {100, 0., 10.}, "pt axis for histograms"};
@@ -283,6 +291,8 @@ struct FlowTask {
     registry.add("hEta", "#eta distribution", {HistType::kTH1D, {axisEta}});
     registry.add("hPt", "p_{T} distribution before cut", {HistType::kTH1D, {axisPtHist}});
     registry.add("hPtRef", "p_{T} distribution after cut", {HistType::kTH1D, {axisPtHist}});
+    registry.add("pt_phi_bef", "before cut;p_{T};#phi_{modn}", {HistType::kTH2D, {axisPt, cfgFuncParas.axisPhiMod}});
+    registry.add("pt_phi_aft", "after cut;p_{T};#phi_{modn}", {HistType::kTH2D, {axisPt, cfgFuncParas.axisPhiMod}});
     registry.add("hChi2prTPCcls", "#chi^{2}/cluster for the TPC track segment", {HistType::kTH1D, {{100, 0., 5.}}});
     registry.add("hChi2prITScls", "#chi^{2}/cluster for the ITS track", {HistType::kTH1D, {{100, 0., 50.}}});
     registry.add("hnTPCClu", "Number of found TPC clusters", {HistType::kTH1D, {{100, 40, 180}}});
@@ -501,6 +511,11 @@ struct FlowTask {
       cfgFuncParas.fT0AV0ASigma->SetParameters(463.4144, 6.796509e-02, -9.097136e-07, 7.971088e-12, -2.600581e-17);
     }
 
+    if (cfgFuncParas.cfgShowTPCsectorOverlap) {
+      cfgFuncParas.fPhiCutLow = new TF1("fPhiCutLow", "0.06/x+pi/18.0-0.06", 0, 100);
+      cfgFuncParas.fPhiCutHigh = new TF1("fPhiCutHigh", "0.1/x+pi/18.0+0.06", 0, 100);
+    }
+
     if (cfgTrackDensityCorrUse) {
       std::vector<double> pTEffBins = {0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.4, 1.8, 2.2, 2.6, 3.0};
       hFindPtBin = new TH1D("hFindPtBin", "hFindPtBin", pTEffBins.size() - 1, &pTEffBins[0]);
@@ -730,12 +745,49 @@ struct FlowTask {
     return 1;
   }
 
+  int getMagneticField(uint64_t timestamp)
+  {
+    static o2::parameters::GRPMagField* grpo = nullptr;
+    if (grpo == nullptr) {
+      grpo = ccdb->getForTimeStamp<o2::parameters::GRPMagField>(cfgFuncParas.cfgMagnetField, timestamp);
+      if (grpo == nullptr) {
+        LOGF(fatal, "GRP object not found in %s for timestamp %llu", cfgFuncParas.cfgMagnetField.value.c_str(), timestamp);
+        return 0;
+      }
+      LOGF(info, "Retrieved GRP from %s for timestamp %llu with magnetic field of %d kG", cfgFuncParas.cfgMagnetField.value.c_str(), timestamp, grpo->getNominalL3Field());
+    }
+    return grpo->getNominalL3Field();
+  }
+
   template <typename TTrack>
   bool trackSelected(TTrack track)
   {
     return ((track.tpcNClsFound() >= cfgCutTPCclu) && (track.tpcNClsCrossedRows() >= cfgCutTPCCrossedRows) && (track.itsNCls() >= cfgCutITSclu));
   }
 
+  template <typename TTrack>
+  bool rejectionTPCoverlap(TTrack track, const int field)
+  {
+    double phimodn = track.phi();
+    if (field < 0) // for negative polarity field
+      phimodn = o2::constants::math::TwoPI - phimodn;
+    if (track.sign() < 0) // for negative charge
+      phimodn = o2::constants::math::TwoPI - phimodn;
+    if (phimodn < 0)
+      LOGF(warning, "phi < 0: %g", phimodn);
+
+    float middle = o2::constants::math::TwoPI / 18.0;
+    phimodn += middle; // to center gap in the middle
+    phimodn = fmod(phimodn, o2::constants::math::TwoPI / 9.0);
+    registry.fill(HIST("pt_phi_bef"), track.pt(), phimodn);
+    if (cfgFuncParas.cfgRejectionTPCsectorOverlap) {
+      if (phimodn < cfgFuncParas.fPhiCutHigh->Eval(track.pt()) && phimodn > cfgFuncParas.fPhiCutLow->Eval(track.pt()))
+        return false; // reject track
+    }
+    registry.fill(HIST("pt_phi_aft"), track.pt(), phimodn);
+    return true;
+  }
+
   void initHadronicRate(aod::BCsWithTimestamps::iterator const& bc)
   {
     if (mRunNumber == bc.runNumber()) {
@@ -844,9 +896,14 @@ struct FlowTask {
     // track weights
     float weff = 1, wacc = 1;
     double nTracksCorrected = 0;
+    int magnetfield = 0;
     float independent = cent;
     if (cfgUseNch)
       independent = static_cast<float>(tracks.size());
+    if (cfgFuncParas.cfgShowTPCsectorOverlap) {
+      // magnet field dependence cut
+      magnetfield = getMagneticField(bc.timestamp());
+    }
 
     double psi2Est = 0, psi3Est = 0, psi4Est = 0;
     float wEPeff = 1;
@@ -879,6 +936,8 @@ struct FlowTask {
     for (const auto& track : tracks) {
       if (!trackSelected(track))
         continue;
+      if (cfgFuncParas.cfgShowTPCsectorOverlap && !rejectionTPCoverlap(track, magnetfield))
+        continue;
       bool withinPtPOI = (cfgCutPtPOIMin < track.pt()) && (track.pt() < cfgCutPtPOIMax); // within POI pT range
       bool withinPtRef = (cfgCutPtRefMin < track.pt()) && (track.pt() < cfgCutPtRefMax); // within RF pT range
       if (cfgOutputNUAWeights) {