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sashingosashingo
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[PWGHF] Implement Z-h correlation (#11938)
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‎PWGHF/HFL/Tasks/taskElectronWeakBoson.cxx‎

Lines changed: 80 additions & 43 deletions
Original file line numberDiff line numberDiff line change
@@ -70,12 +70,14 @@ struct HfTaskElectronWeakBoson {
7070

7171
Configurable<float> vtxZ{"vtxZ", 10.f, ""};
7272

73-
Configurable<float> etaTrMim{"etaTrMim", -1.0f, "minimun track eta"};
73+
Configurable<float> etaTrMin{"etaTrMin", -1.0f, "minimun track eta"};
7474
Configurable<float> etaTrMax{"etaTrMax", 1.0f, "maximum track eta"};
7575
Configurable<float> etaEmcMax{"etaEmcMax", 0.6f, "maximum track eta"};
7676
Configurable<float> dcaxyMax{"dcaxyMax", 2.0f, "mximum DCA xy"};
7777
Configurable<float> chi2ItsMax{"chi2ItsMax", 15.0f, "its chi2 cut"};
7878
Configurable<float> ptMin{"ptMin", 3.0f, "minimum pT cut"};
79+
Configurable<float> ptAssMin{"ptAssMin", 0.15, "minimum pT cut for associated hadrons"};
80+
Configurable<float> ptMatch{"ptMatch", 0.001, "pT match in Z->ee and associated tracks"};
7981
Configurable<float> ptZeeMin{"ptZeeMin", 20.0f, "minimum pT cut for Zee"};
8082
Configurable<float> chi2TpcMax{"chi2TpcMax", 4.0f, "tpc chi2 cut"};
8183
Configurable<float> nclItsMin{"nclItsMin", 2.0f, "its # of cluster cut"};
@@ -100,6 +102,9 @@ struct HfTaskElectronWeakBoson {
100102
Configurable<float> energyIsolationMax{"energyIsolationMax", 0.1, "isolation cut on energy"};
101103
Configurable<int> trackIsolationMax{"trackIsolationMax", 3, "Maximum number of tracks in isolation cone"};
102104

105+
Configurable<float> massZMin{"massZMin", 60.0, "Minimum Z mass (GeV/c^2)"};
106+
Configurable<float> massZMax{"massZMax", 120.0, "Maximum Z mass (GeV/c^2)"};
107+
103108
// flag for THn
104109
Configurable<bool> isTHnElectron{"isTHnElectron", true, "Enables THn for electrons"};
105110
Configurable<float> ptTHnThresh{"ptTHnThresh", 5.0, "Threshold for THn make"};
@@ -114,7 +119,7 @@ struct HfTaskElectronWeakBoson {
114119

115120
// KFParticle
116121
Configurable<int> kfConstructMethod{"kfConstructMethod", 2, "KF Construct Method"};
117-
Configurable<int> kfChisqMassMax{"kfChisqMassMax", 10, "Chi2 Max for mass reco by KF particle"};
122+
Configurable<int> chiSqNdfMax{"chiSqNdfMax", 10, "Chi2 Max for mass reco by KF particle"};
118123

119124
// CCDB service object
120125
Service<o2::ccdb::BasicCCDBManager> ccdb;
@@ -129,7 +134,14 @@ struct HfTaskElectronWeakBoson {
129134
};
130135
std::vector<HfElectronCandidate> selectedElectronsIso;
131136
std::vector<HfElectronCandidate> selectedElectronsAss;
132-
std::vector<HfElectronCandidate> reconstructedZ;
137+
138+
struct HfZeeCandidate {
139+
float pt, eta, phi, mass, ptchild0, ptchild1;
140+
int charge;
141+
HfZeeCandidate(float ptr, float e, float ph, float m, int ch, float ptzee0, float ptzee1)
142+
: pt(ptr), eta(e), phi(ph), mass(m), ptchild0(ptzee0), ptchild1(ptzee1), charge(ch) {}
143+
};
144+
std::vector<HfZeeCandidate> reconstructedZ;
133145

134146
using SelectedClusters = o2::aod::EMCALClusters;
135147
// PbPb
@@ -143,7 +155,7 @@ struct HfTaskElectronWeakBoson {
143155
Filter eventFilter = (o2::aod::evsel::sel8 == true);
144156
Filter posZFilter = (nabs(o2::aod::collision::posZ) < vtxZ);
145157

146-
Filter etafilter = (aod::track::eta < etaTrMax) && (aod::track::eta > etaTrMim);
158+
Filter etafilter = (aod::track::eta < etaTrMax) && (aod::track::eta > etaTrMin);
147159
Filter dcaxyfilter = (nabs(aod::track::dcaXY) < dcaxyMax);
148160
Filter filterGlobalTr = requireGlobalTrackInFilter();
149161

@@ -200,6 +212,9 @@ struct HfTaskElectronWeakBoson {
200212
const AxisSpec axisIsoTrack{15, -0.5, 14.5, "Isolation Track"};
201213
const AxisSpec axisInvMassZ{150, 0, 150, "M_{ee} (GeV/c^{2})"};
202214
const AxisSpec axisTrigger{3, -0.5, 2.5, "Trigger status of zorro"};
215+
const AxisSpec axisDPhiZh{64, -o2::constants::math::PIHalf, 3 * o2::constants::math::PIHalf, "#Delta#phi(Z-h)"};
216+
const AxisSpec axisPtHadron{50, 0, 50, "p_{T,hadron} (GeV/c)"};
217+
const AxisSpec axisZpt{150, 0, 150, "p_{T,Z} (GeV/c)"};
203218

204219
// create registrygrams
205220
registry.add("hZvtx", "Z vertex", kTH1F, {axisZvtx});
@@ -233,6 +248,10 @@ struct HfTaskElectronWeakBoson {
233248
registry.add("hTHnElectrons", "electron info", HistType::kTHnSparseF, {axisPt, axisNsigma, axisM02, axisEop, axisIsoEnergy, axisIsoTrack});
234249
registry.add("hTHnTrMatch", "Track EMC Match", HistType::kTHnSparseF, {axisPt, axisdPhi, axisdEta});
235250

251+
// Z-hadron correlation histograms
252+
registry.add("hZHadronDphi", "Z-hadron #Delta#phi correlation", kTH2F, {{axisZpt}, {axisDPhiZh}});
253+
registry.add("hZptSpectrum", "Z boson p_{T} spectrum", kTH1F, {axisZpt});
254+
236255
// hisotgram for EMCal trigger
237256
registry.add("hEMCalTrigger", "EMCal trigger", kTH1F, {axisTrigger});
238257
}
@@ -302,46 +321,61 @@ struct HfTaskElectronWeakBoson {
302321
// LOG(info) << "Invarimass cal by KF particle ";
303322
for (const auto& track : tracks) {
304323

305-
if (track.pt() < ptZeeMin)
324+
if (track.pt() < ptZeeMin) {
306325
continue;
307-
if (std::abs(track.tpcNSigmaEl()) > nsigTpcMax)
326+
}
327+
if (std::abs(track.tpcNSigmaEl()) > nsigTpcMax) {
308328
continue;
309-
if (std::abs(track.eta()) > etaTrMax)
329+
}
330+
if (std::abs(track.eta()) > etaTrMax) {
310331
continue;
311-
332+
}
312333
int pdgAss = kElectron;
313334
if (track.sign() > 0) {
314335
pdgAss = kPositron;
315336
}
316337

317338
KFPTrack kfpTrackAssEle = createKFPTrackFromTrack(track);
318339
KFParticle kfpAssEle(kfpTrackAssEle, pdgAss);
340+
// reco by RecoDecay
341+
auto child1 = RecoDecayPtEtaPhi::pVector(kfpIsoEle.GetPt(), kfpIsoEle.GetEta(), kfpIsoEle.GetPhi());
342+
auto child2 = RecoDecayPtEtaPhi::pVector(kfpAssEle.GetPt(), kfpAssEle.GetEta(), kfpAssEle.GetPhi());
343+
double invMassEE = RecoDecay::m(std::array{child1, child2}, std::array{o2::constants::physics::MassElectron, o2::constants::physics::MassElectron});
344+
345+
// reco by KFparticle
319346
const KFParticle* electronPairs[2] = {&kfpIsoEle, &kfpAssEle};
320347
KFParticle zeeKF;
321348
zeeKF.SetConstructMethod(kfConstructMethod);
322349
zeeKF.Construct(electronPairs, 2);
323350
// LOG(info) << "Invarimass cal by KF particle Chi2/NDF = " << zeeKF.GetChi2()/zeeKF.GetNDF();
324-
float massZeeChi2 = zeeKF.GetChi2() / zeeKF.GetNDF();
325-
if (zeeKF.GetNDF() < 1)
351+
float chiSqNdf = zeeKF.GetChi2() / zeeKF.GetNDF();
352+
if (zeeKF.GetNDF() < 1) {
326353
continue;
327-
if (std::abs(massZeeChi2) > kfChisqMassMax)
354+
}
355+
if (chiSqNdf > chiSqNdfMax) {
328356
continue;
357+
}
329358
float massZee, massZeeErr;
330359
zeeKF.GetMass(massZee, massZeeErr);
331360
// LOG(info) << "Invarimass cal by KF particle mass = " << massZee;
361+
// LOG(info) << "Invarimass cal by RecoDecay = " << invMassEE;
332362

333363
if (track.sign() * charge > 0) {
334364
registry.fill(HIST("hKfInvMassZeeLs"), kfpIsoEle.GetPt(), massZee);
365+
registry.fill(HIST("hInvMassZeeLs"), kfpIsoEle.GetPt(), invMassEE);
335366
} else {
336367
registry.fill(HIST("hKfInvMassZeeUls"), kfpIsoEle.GetPt(), massZee);
368+
registry.fill(HIST("hInvMassZeeUls"), kfpIsoEle.GetPt(), invMassEE);
337369
}
338370

339371
reconstructedZ.emplace_back(
340372
zeeKF.GetPt(),
341373
zeeKF.GetEta(),
342374
zeeKF.GetPhi(),
343375
massZee,
344-
track.sign() * charge);
376+
track.sign() * charge,
377+
kfpIsoEle.GetPt(),
378+
kfpAssEle.GetPt());
345379
}
346380
}
347381

@@ -409,22 +443,27 @@ struct HfTaskElectronWeakBoson {
409443

410444
for (const auto& track : tracks) {
411445

412-
if (std::abs(track.eta()) > etaTrMax)
413-
continue;
414-
if (track.tpcNClsCrossedRows() < nclcrossTpcMin)
446+
if (std::abs(track.eta()) > etaTrMax) {
415447
continue;
416-
if (std::abs(track.dcaXY()) > dcaxyMax)
448+
}
449+
if (track.tpcNClsCrossedRows() < nclcrossTpcMin) {
417450
continue;
418-
if (track.itsChi2NCl() > chi2ItsMax)
451+
}
452+
if (std::abs(track.dcaXY()) > dcaxyMax) {
419453
continue;
420-
if (track.tpcChi2NCl() > chi2TpcMax)
454+
}
455+
if (track.itsChi2NCl() > chi2ItsMax) {
421456
continue;
422-
if (track.tpcNClsFound() < nclTpcMin)
457+
}
458+
if (track.tpcChi2NCl() > chi2TpcMax) {
423459
continue;
424-
if (track.itsNCls() < nclItsMin)
460+
}
461+
if (track.tpcNClsFound() < nclTpcMin) {
425462
continue;
426-
if (track.pt() < ptMin)
463+
}
464+
if (track.itsNCls() < nclItsMin) {
427465
continue;
466+
}
428467

429468
registry.fill(HIST("hEta"), track.eta());
430469
registry.fill(HIST("hITSchi2"), track.itsChi2NCl());
@@ -437,7 +476,7 @@ struct HfTaskElectronWeakBoson {
437476

438477
float energyTrk = 0.0;
439478

440-
if (track.tpcNSigmaEl() > nsigTpcMinLose && track.tpcNSigmaEl() < nsigTpcMax && track.pt() > ptZeeMin) {
479+
if (track.pt() > ptAssMin) {
441480
selectedElectronsAss.emplace_back(
442481
track.pt(),
443482
track.eta(),
@@ -446,6 +485,9 @@ struct HfTaskElectronWeakBoson {
446485
track.sign());
447486
}
448487

488+
if (track.pt() < ptMin) {
489+
continue;
490+
}
449491
// track - match
450492

451493
// continue;
@@ -550,7 +592,6 @@ struct HfTaskElectronWeakBoson {
550592
}
551593
}
552594
}
553-
554595
nMatch++;
555596
}
556597
}
@@ -561,30 +602,26 @@ struct HfTaskElectronWeakBoson {
561602
}
562603

563604
} // end of track loop
564-
565-
// calculate inv. mass
566-
if (selectedElectronsIso.size() > 0) {
567-
for (size_t i = 0; i < selectedElectronsIso.size(); i++) {
568-
const auto& e1 = selectedElectronsIso[i];
569-
for (size_t j = 0; j < selectedElectronsAss.size(); j++) {
570-
const auto& e2 = selectedElectronsAss[j];
571-
572-
float ptIso = e1.pt;
573-
float ptAss = e2.pt;
574-
if (ptIso == ptAss)
605+
// Z-hadron
606+
if (reconstructedZ.size() > 0) {
607+
for (const auto& zBoson : reconstructedZ) {
608+
// Z boson selection
609+
if (zBoson.mass < massZMin || zBoson.mass > massZMax)
610+
continue;
611+
registry.fill(HIST("hZptSpectrum"), zBoson.pt);
612+
for (const auto& trackAss : selectedElectronsAss) {
613+
if (std::abs(trackAss.pt - zBoson.ptchild0) < ptMatch) {
614+
continue;
615+
}
616+
if (std::abs(trackAss.pt - zBoson.ptchild1) < ptMatch) {
575617
continue;
576-
auto arr1 = RecoDecayPtEtaPhi::pVector(e1.pt, e1.eta, e1.phi);
577-
auto arr2 = RecoDecayPtEtaPhi::pVector(e2.pt, e2.eta, e2.phi);
578-
double mass = RecoDecay::m(std::array{arr1, arr2}, std::array{o2::constants::physics::MassElectron, o2::constants::physics::MassElectron});
579-
580-
if (e1.sign() * e2.sign() > 0) {
581-
registry.fill(HIST("hInvMassZeeLs"), ptIso, mass);
582-
} else {
583-
registry.fill(HIST("hInvMassZeeUls"), ptIso, mass);
584618
}
619+
// calculate Z-h correlation
620+
double deltaPhi = RecoDecay::constrainAngle(trackAss.phi - zBoson.phi, -o2::constants::math::PIHalf);
621+
registry.fill(HIST("hZHadronDphi"), zBoson.pt, deltaPhi);
585622
}
586623
}
587-
} // end of inv. mass calculation
624+
} // end of Z-hadron correlation
588625
}
589626
};
590627

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