optimization and bug fix in two track cut

diff --git a/PWGCF/Correlations/Base/AliUEHistograms.cxx b/PWGCF/Correlations/Base/AliUEHistograms.cxx
index d37e7730358283fac76146d6487a53f7951c9e4c..bc36501f2ecbfbc0767aeb6ebd3cfbdebb0cded6 100644 (file)
--- a/PWGCF/Correlations/Base/AliUEHistograms.cxx
+++ b/PWGCF/Correlations/Base/AliUEHistograms.cxx
@@ -436,6 +436,12 @@ void AliUEHistograms::FillCorrelations(Double_t centrality, Float_t zVtx, AliUEH
   if (weight < 0)
     fillpT = kTRUE;
   
+  if (twoTrackEfficiencyCut && !fTwoTrackDistancePt[0])
+  {
+    fTwoTrackDistancePt[0] = new TH3F("fTwoTrackDistancePt[0]", ";#Delta#eta;#Delta#varphi^{*}_{min};#Delta p_{T}", 100, -0.05, 0.05, 100, -0.05, 0.05, 20, 0, 10);
+    fTwoTrackDistancePt[1] = (TH3F*) fTwoTrackDistancePt[0]->Clone("fTwoTrackDistancePt[1]");
+  }
+
   // Eta() is extremely time consuming, therefore cache it for the inner loop here:
   TObjArray* input = (mixed) ? mixed : particles;
   TArrayF eta(input->GetEntriesFast());
@@ -526,6 +532,9 @@ void AliUEHistograms::FillCorrelations(Double_t centrality, Float_t zVtx, AliUEH
        
        if (twoTrackEfficiencyCut)
        {
+         // the variables & cuthave been developed by the HBT group 
+         // see e.g. https://indico.cern.ch/materialDisplay.py?contribId=36&sessionId=6&materialId=slides&confId=142700
+
          Float_t phi1 = triggerParticle->Phi();
          Float_t pt1 = triggerParticle->Pt();
          Float_t charge1 = triggerParticle->Charge();
@@ -537,25 +546,41 @@ void AliUEHistograms::FillCorrelations(Double_t centrality, Float_t zVtx, AliUEH
          Float_t deta = triggerEta - eta[j];
              
          // optimization
-         if (TMath::Abs(deta) < 0.02)
+         if (TMath::Abs(deta) < 0.05)
          {
-           Float_t dphistarmin = 1e5;
-           Float_t dphistarminabs = 1e5;
+           // check first boundaries to see if is worth to loop and find the minimum
+           Float_t dphistar1 = GetDPhiStar(phi1, pt1, charge1, phi2, pt2, charge2, 0.8, bSign);
+           Float_t dphistar2 = GetDPhiStar(phi1, pt1, charge1, phi2, pt2, charge2, 2.5, bSign);
+           
+           const Float_t kLimit = 0.06;
 
-           for (Double_t rad=0.8; rad<2.51; rad+=0.05) 
+           Float_t dphistarminabs = 1e5;
+           Float_t dphistarmin = 1e5;
+           if (TMath::Abs(dphistar1) < kLimit || TMath::Abs(dphistar2) < kLimit || dphistar1 * dphistar2 < 0)
            {
-             Float_t dphistar = phi1 - phi2 - TMath::ASin(charge1 * 0.075 * bSign * rad / pt1) + TMath::ASin(charge2 * 0.075 * bSign * rad / pt2);
-             Float_t dphistarabs = TMath::Abs(dphistar);
+             for (Double_t rad=0.8; rad<2.51; rad+=0.01) 
+             {
+               Float_t dphistar = GetDPhiStar(phi1, pt1, charge1, phi2, pt2, charge2, rad, bSign);
+
+               Float_t dphistarabs = TMath::Abs(dphistar);
+               
+               if (dphistarabs < dphistarminabs)
+               {
+                 dphistarmin = dphistar;
+                 dphistarminabs = dphistarabs;
+               }
+             }
+             
+             fTwoTrackDistancePt[0]->Fill(deta, dphistarmin, TMath::Abs(pt1 - pt2));
              
-             if (dphistarabs < dphistarminabs)
+             if (dphistarminabs < 0.02 && TMath::Abs(deta) < 0.02)
              {
-               dphistarmin = dphistar;
-               dphistarminabs = dphistarabs;
+//             Printf("Removed track pair %d %d with %f %f %f %f %f %f %f %f %f", i, j, deta, dphistarminabs, phi1, pt1, charge1, phi2, pt2, charge2, bSign);
+               continue;
              }
+
+             fTwoTrackDistancePt[1]->Fill(deta, dphistarmin, TMath::Abs(pt1 - pt2));
            }
-           
-           if (dphistarminabs < 0.02)
-             continue;
          }
        }
         
@@ -929,97 +954,6 @@ void AliUEHistograms::Reset()
       GetUEHist(i)->Reset();
 }
 
-void AliUEHistograms::TwoTrackEfficiency(TObjArray* tracks, TObjArray* mixed, Float_t bSign)
-{
-  // takes the input list <tracks> and fills histograms to study two two-track efficiency effects
-  // fTwoTrackDistancePt[i] (i = 0 same, i = 1 mixed)
-  //
-  // the variables have been developed by the HBT group 
-  // see e.g. https://indico.cern.ch/materialDisplay.py?contribId=36&sessionId=6&materialId=slides&confId=142700
-  
-  if (!fTwoTrackDistancePt[0])
-  {
-    fTwoTrackDistancePt[0] = new TH3F("fTwoTrackDistancePt[0]", ";#Delta#eta;#Delta#varphi^{*}_{min};#Delta p_{T}", 100, -0.05, 0.05, 400, -0.2, 0.2, 20, 0, 10);
-    fTwoTrackDistancePt[1] = (TH3F*) fTwoTrackDistancePt[0]->Clone("fTwoTrackDistancePt[1]");
-  }
-
-  // Eta() is extremely time consuming, therefore cache it for the inner loop here:
-  TArrayF eta1(tracks->GetEntriesFast());
-  for (Int_t i=0; i<tracks->GetEntriesFast(); i++)
-    eta1[i] = ((AliVParticle*) tracks->At(i))->Eta();
-  
-  Int_t jMax = tracks->GetEntriesFast();
-  if (mixed)
-    jMax = mixed->GetEntriesFast();
-  
-  TArrayF eta2(jMax);
-  if (!mixed)
-    eta2 = eta1;
-  else
-    for (Int_t i=0; i<mixed->GetEntriesFast(); i++)
-      eta2[i] = ((AliVParticle*) mixed->At(i))->Eta();
-
-  for (Int_t i=0; i<tracks->GetEntriesFast(); i++)
-  {
-    AliVParticle* particle1 = (AliVParticle*) tracks->At(i);
-    Float_t phi1 = particle1->Phi();
-    Float_t pt1 = particle1->Pt();
-    Float_t charge1 = particle1->Charge();
-    
-    for (Int_t j=0; j<jMax; j++)
-    {
-      if (!mixed && i == j)
-       continue;
-      
-      AliVParticle* particle2 = 0;
-      if (mixed)
-       particle2 = (AliVParticle*) mixed->At(j);
-      else
-       particle2 = (AliVParticle*) tracks->At(j);
-      Float_t phi2 = particle2->Phi();
-      Float_t pt2 = particle2->Pt();
-      Float_t charge2 = particle2->Charge();
-      
-      if (pt2 > pt1)
-       continue;
-      
-//       Double_t dpt = TMath::Abs(pt1 - pt2);
-      Float_t deta = eta1[i] - eta2[j];
-      Float_t detaabs = TMath::Abs(deta);
-      
-      // optimization
-      if (detaabs > 0.05 && (pt1 < 8 || pt1 > 15))
-       continue;
-      
-      Float_t dphistarmin = 1e5;
-      Float_t dphistarminabs = 1e5;
-
-      for (Double_t rad=0.8; rad<2.51; rad+=0.01) 
-      {
-       Float_t dphistar = phi1 - phi2 - TMath::ASin(charge1 * 0.075 * bSign * rad / pt1) + TMath::ASin(charge2 * 0.075 * bSign * rad / pt2);
-       Float_t dphistarabs = TMath::Abs(dphistar);
-       
-       if (dphistarabs < dphistarminabs)
-       {
-         dphistarmin = dphistar;
-         dphistarminabs = dphistarabs;
-       }
-      }
-
-      Float_t fillPt = pt2;
-      
-      // analyze region for IAA paper
-      if (pt1 < 8 || pt1 > 15)
-       fillPt = 0.25;
-    
-      if (!mixed)
-       fTwoTrackDistancePt[0]->Fill(deta, dphistarmin, fillPt);
-      else
-       fTwoTrackDistancePt[1]->Fill(deta, dphistarmin, fillPt);
-    }
-  }
-}
-
 Float_t AliUEHistograms::GetInvMassSquared(Float_t pt1, Float_t eta1, Float_t phi1, Float_t pt2, Float_t eta2, Float_t phi2, Float_t m0)
 {
   // calculate inv mass squared

diff --git a/PWGCF/Correlations/Base/AliUEHistograms.h b/PWGCF/Correlations/Base/AliUEHistograms.h
index c468cf3198c5579a955ed281b89d6d078b8defd1..125ea7a1c557e64100b947f88c518d099b6659a7 100644 (file)
--- a/PWGCF/Correlations/Base/AliUEHistograms.h
+++ b/PWGCF/Correlations/Base/AliUEHistograms.h
@@ -10,6 +10,7 @@
 
 #include "TNamed.h"
 #include "AliUEHist.h"
+#include "TMath.h"
 
 class AliVParticle;
 
@@ -33,8 +34,6 @@ class AliUEHistograms : public TNamed
   void FillEvent(Double_t centrality, Int_t step);
   void FillTrackingEfficiency(TObjArray* mc, TObjArray* recoPrim, TObjArray* recoAll, Int_t particleType, Double_t centrality = 0);
   
-  void TwoTrackEfficiency(TObjArray* tracks, TObjArray* mixed, Float_t bSign);
-  
   void CopyReconstructedData(AliUEHistograms* from);
   
   AliUEHist* GetUEHist(Int_t id);
@@ -90,6 +89,7 @@ protected:
   Int_t CountParticles(TList* list, Float_t ptMin);
   void DeleteContainers();
   Float_t GetInvMassSquared(Float_t pt1, Float_t eta1, Float_t phi1, Float_t pt2, Float_t eta2, Float_t phi2, Float_t m0);
+  inline Float_t GetDPhiStar(Float_t phi1, Float_t pt1, Float_t charge1, Float_t phi2, Float_t pt2, Float_t charge2, Float_t radius, Float_t bSign);
   
   static const Int_t fgkUEHists; // number of histograms
 
@@ -126,4 +126,30 @@ protected:
   ClassDef(AliUEHistograms, 13)  // underlying event histogram container
 };
 
+Float_t AliUEHistograms::GetDPhiStar(Float_t phi1, Float_t pt1, Float_t charge1, Float_t phi2, Float_t pt2, Float_t charge2, Float_t radius, Float_t bSign)
+{ 
+  //
+  // calculates dphistar
+  //
+  
+  Float_t dphistar = phi1 - phi2 - charge1 * bSign * TMath::ASin(0.075 * radius / pt1) + charge2 * bSign * TMath::ASin(0.075 * radius / pt2);
+  
+  static const Double_t kPi = TMath::Pi();
+  
+  // circularity
+//   if (dphistar > 2 * kPi)
+//     dphistar -= 2 * kPi;
+//   if (dphistar < -2 * kPi)
+//     dphistar += 2 * kPi;
+  
+  if (dphistar > kPi)
+    dphistar = kPi * 2 - dphistar;
+  if (dphistar < -kPi)
+    dphistar = -kPi * 2 - dphistar;
+  if (dphistar > kPi) // might look funny but is needed
+    dphistar = kPi * 2 - dphistar;
+  
+  return dphistar;
+}
+
 #endif

diff --git a/PWGCF/Correlations/DPhi/AliAnalysisTaskPhiCorrelations.cxx b/PWGCF/Correlations/DPhi/AliAnalysisTaskPhiCorrelations.cxx
index 2db04542a78a6b33cc11b9f0be61ed49b58329d9..3e110ea95a1499668b311147cb98ae24d310c1f0 100644 (file)
--- a/PWGCF/Correlations/DPhi/AliAnalysisTaskPhiCorrelations.cxx
+++ b/PWGCF/Correlations/DPhi/AliAnalysisTaskPhiCorrelations.cxx
@@ -650,13 +650,9 @@ void  AliAnalysisTaskPhiCorrelations::AnalyseDataMode()
     ((TH1F*) fListOfHistos->FindObject("eventStat"))->Fill(1);
     
     if (fTwoTrackEfficiencyCut)
-      fHistos->FillCorrelations(centrality, zVtx, AliUEHist::kCFStepBiasStudy, tracksClone, 0, weight, kTRUE, bSign);
+      fHistos->FillCorrelations(centrality, zVtx, AliUEHist::kCFStepBiasStudy, tracksClone, 0, weight, kTRUE, kTRUE, bSign);
   }
 
-  // Two-track effect study
-  if (fTwoTrackEfficiencyStudy)
-    fHistos->TwoTrackEfficiency(tracksClone, 0, bSign);
-  
   // fill second time with SPD centrality
   if (fCompareCentralities && centralityObj)
   {
@@ -664,7 +660,7 @@ void  AliAnalysisTaskPhiCorrelations::AnalyseDataMode()
     if (centrality >= 0)
       fHistos->FillCorrelations(centrality, 2, AliUEHist::kCFStepReconstructed, tracksClone, 0, weight);
   }
-    
+  
   if (fFillMixed)
   {
     // event mixing
@@ -708,9 +704,6 @@ void  AliAnalysisTaskPhiCorrelations::AnalyseDataMode()
       {
        TObjArray* bgTracks = pool->GetEvent(jMix);
        
-       if (fTwoTrackEfficiencyStudy)
-         fHistos->TwoTrackEfficiency(tracksClone, bgTracks, bSign);
-
        fHistosMixed->FillCorrelations(centrality, zVtx, AliUEHist::kCFStepReconstructed, tracksClone, bgTracks, 1.0 / nMix, (jMix == 0));
 
        if (fTwoTrackEfficiencyCut)