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[PWGCF] Updating PID strategy #16370

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Merged
wenyaCern merged 1 commit into from
May 26, 2026
Merged

[PWGCF] Updating PID strategy #16370

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116 changes: 99 additions & 17 deletions PWGCF/TwoParticleCorrelations/Tasks/nucleibalance.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -1677,6 +1677,10 @@ struct Lambdastarproxy {
static constexpr float TofBetaMin = 0.01f;
static constexpr float TofBetaMax = 1.2f;
static constexpr double Half = 0.5;
// PID strategy values
static constexpr int PidStrategyRectangular = 0;
static constexpr int PidStrategyCircularTPCAndTOF = 1;
static constexpr int PidStrategyTOFOnly = 2;
// Basic configuration for event and track selection
Configurable<float> lstarCutVertex{"lstarCutVertex", float{CutVertexDefault}, "Accepted z-vertex range (cm)"};
Configurable<float> lstarCutPtMin{"lstarCutPtMin", float{CutPtMinDefault}, "Minimal pT for tracks (GeV/c)"};
Expand All @@ -1696,6 +1700,24 @@ struct Lambdastarproxy {
Configurable<float> lstarCutNsigmaTOFKaon{"lstarCutNsigmaTOFKaon", float{NsigmaTOFDefault}, "|nSigma^{TOF}_{K}| cut"};
Configurable<float> lstarCutNsigmaTPCDe{"lstarCutNsigmaTPCDe", float{NsigmaTPCDefault}, "|nSigma^{TPC}_{d}| cut"};
Configurable<float> lstarCutNsigmaTOFDe{"lstarCutNsigmaTOFDe", float{NsigmaTOFDefault}, "|nSigma^{TOF}_{d}| cut"};
// PID strategy for final K/p/d candidate selection.
// 0 = rectangular cuts: |TPC| < cut and, if TOF exists, |TOF| < cut
// 1 = pT-ref dependent circular cut:
// pT < pTref: require |TPC| < TPC cut only
// pT >= pTref and TOF exists: require sqrt(TPC^2 + TOF^2) < circular cut
// pT >= pTref and TOF missing: reject
// 2 = TOF-only above pTref:
// pT < pTref: require |TPC| < TPC cut only
// pT >= pTref: require TOF hit and |TOF| < TOF cut
Configurable<int> lstarPidStrategy{"lstarPidStrategy", int{PidStrategyRectangular}, "PID strategy: 0=rectangular TPC/TOF, 1=pTref circular TPC+TOF, 2=pTref TOF-only"};

Configurable<float> lstarPidCircularCutKaon{"lstarPidCircularCutKaon", 2.0f, "Circular PID cut sqrt(nSigmaTPC_K^2+nSigmaTOF_K^2) for kaons"};
Configurable<float> lstarPidCircularCutPr{"lstarPidCircularCutPr", 2.0f, "Circular PID cut sqrt(nSigmaTPC_p^2+nSigmaTOF_p^2) for protons"};
Configurable<float> lstarPidCircularCutDe{"lstarPidCircularCutDe", 2.0f, "Circular PID cut sqrt(nSigmaTPC_d^2+nSigmaTOF_d^2) for deuterons"};

Configurable<float> lstarPidPtRefKaon{"lstarPidPtRefKaon", 0.5f, "pT reference for kaon PID strategy"};
Configurable<float> lstarPidPtRefPr{"lstarPidPtRefPr", 0.8f, "pT reference for proton PID strategy"};
Configurable<float> lstarPidPtRefDe{"lstarPidPtRefDe", 0.8f, "pT reference for deuteron PID strategy"};

// Track quality
Configurable<bool> lstarRequireGlobalTrack{"lstarRequireGlobalTrack", bool{RequireGlobalTrackDefault}, "Require global tracks (default)"};
Expand Down Expand Up @@ -2305,6 +2327,45 @@ struct Lambdastarproxy {
return true; // fallback: if column not present, assume available
}

bool passFinalCandidatePID(float pt,
float nsTPC,
float nsTOF,
bool hasTof,
float tpcCut,
float tofCut,
float circularCut,
float ptRef) const
{
// Strategy 1: analysis-note style circular TPC+TOF cut
if (lstarPidStrategy.value == PidStrategyCircularTPCAndTOF) {
if (pt < ptRef) {
return std::abs(nsTPC) < tpcCut;
}

if (!hasTof) {
return false;
}

return std::sqrt(nsTPC * nsTPC + nsTOF * nsTOF) < circularCut;
}

// Strategy 2: TOF-only above pTref
if (lstarPidStrategy.value == PidStrategyTOFOnly) {
if (pt < ptRef) {
return std::abs(nsTPC) < tpcCut;
}

if (!hasTof) {
return false;
}

return std::abs(nsTOF) < tofCut;
}

// Strategy 0: old rectangular logic
return (std::abs(nsTPC) < tpcCut) && (!hasTof || (std::abs(nsTOF) < tofCut));
}

// Return: 0=#pi, 1=K, 2=p, 3=d, -1=unclassified
template <typename TTrack>
int classifyPidSpecies(const TTrack& trk)
Expand Down Expand Up @@ -2580,20 +2641,27 @@ struct Lambdastarproxy {
continue;
}

// Deuteron kinematics needed before PID because the PID strategy can depend on pT
const float ptD = trkD.pt();
const float etaD = trkD.eta();
const float phiD = trkD.phi();

// PID for deuteron candidates
const float nsTPCDe = trkD.tpcNSigmaDe();
const float nsTOFDe = trkD.tofNSigmaDe();
const bool hasTofDe = hasTOFMatch(trkD);
const bool isDeuteron = (std::abs(nsTPCDe) < lstarCutNsigmaTPCDe.value) &&
(!hasTofDe || (std::abs(nsTOFDe) < lstarCutNsigmaTOFDe.value));
const bool isDeuteron = passFinalCandidatePID(ptD,
nsTPCDe,
nsTOFDe,
hasTofDe,
lstarCutNsigmaTPCDe.value,
lstarCutNsigmaTOFDe.value,
lstarPidCircularCutDe.value,
lstarPidPtRefDe.value);
if (!isDeuteron) {
continue;
}

// Deuteron kinematics
const float ptD = trkD.pt();
const float etaD = trkD.eta();
const float phiD = trkD.phi();
const double pD = static_cast<double>(ptD) * std::cosh(static_cast<double>(etaD));

// QA histos for deuteron PID and kinematics
Expand Down Expand Up @@ -2642,18 +2710,25 @@ struct Lambdastarproxy {
continue;
}

const float ptP = trkP.pt();
const float etaP = trkP.eta();
const float phiP = trkP.phi();

const float nsTPCPr = trkP.tpcNSigmaPr();
const float nsTOFPr = trkP.tofNSigmaPr();
const bool hasTofPr = hasTOFMatch(trkP);
const bool isProton = (std::abs(nsTPCPr) < lstarCutNsigmaTPCPr.value) &&
(!hasTofPr || (std::abs(nsTOFPr) < lstarCutNsigmaTOFPr.value));
const bool isProton = passFinalCandidatePID(ptP,
nsTPCPr,
nsTOFPr,
hasTofPr,
lstarCutNsigmaTPCPr.value,
lstarCutNsigmaTOFPr.value,
lstarPidCircularCutPr.value,
lstarPidPtRefPr.value);
if (!isProton) {
continue;
}

const float ptP = trkP.pt();
const float etaP = trkP.eta();
const float phiP = trkP.phi();
const double pP = static_cast<double>(ptP) * std::cosh(static_cast<double>(etaP));

if (lstarEnablePidQA.value != 0) {
Expand Down Expand Up @@ -2695,20 +2770,27 @@ struct Lambdastarproxy {
continue;
}

// Kaon kinematics needed before PID because the PID strategy can depend on pT
const float ptK = trkK.pt();
const float etaK = trkK.eta();
const float phiK = trkK.phi();

// PID for kaon candidates
const float nsTPCK = trkK.tpcNSigmaKa();
const float nsTOFK = trkK.tofNSigmaKa();
const bool hasTofK = hasTOFMatch(trkK);
const bool isKaon = (std::abs(nsTPCK) < lstarCutNsigmaTPCKaon.value) &&
(!hasTofK || (std::abs(nsTOFK) < lstarCutNsigmaTOFKaon.value));
const bool isKaon = passFinalCandidatePID(ptK,
nsTPCK,
nsTOFK,
hasTofK,
lstarCutNsigmaTPCKaon.value,
lstarCutNsigmaTOFKaon.value,
lstarPidCircularCutKaon.value,
lstarPidPtRefKaon.value);
if (!isKaon) {
continue;
}

// Kaon kinematics
const float ptK = trkK.pt();
const float etaK = trkK.eta();
const float phiK = trkK.phi();
const double pK = static_cast<double>(ptK) * std::cosh(static_cast<double>(etaK));

// Kaon QA
Expand Down
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