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SteffimroSteffimro
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[PWGEM] fix MC truth information + cross-pair ratio (#17236)
1 parent dddd07e commit 83a780b

1 file changed

Lines changed: 24 additions & 51 deletions

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‎PWGEM/PhotonMeson/Tasks/photonhbt.cxx‎

Lines changed: 24 additions & 51 deletions
Original file line numberDiff line numberDiff line change
@@ -152,8 +152,8 @@ struct Photonhbt {
152152
};
153153

154154
struct CrossObs {
155-
std::array<float, 2> mee{999.f, 999.f}; // crossed m(e+e-) per combo
156-
std::array<float, 2> dist{999.f, 999.f}; // crossed line-line distance (cm)
155+
std::array<float, 2> mee{999.f, 999.f};
156+
float meeOverQ{999.f};
157157
};
158158

159159
struct TruthGamma {
@@ -350,8 +350,7 @@ struct Photonhbt {
350350
std::string prefix = "crosspair_group";
351351
Configurable<bool> cfgDoCrossPairQA{"cfgDoCrossPairQA", false, "fill crossed-hypothesis QA (mee_cross, dist_cross vs qinv) for pairs passing all other pair cuts; SE and ME"};
352352
Configurable<bool> cfgDoCrossPairCut{"cfgDoCrossPairCut", false, "reject pairs with a photon-like crossed combination; applied to SE AND ME"};
353-
Configurable<float> cfgCrossMaxMee{"cfgCrossMaxMee", 0.04f, "veto: crossed m_ee below this (GeV/c^2)"};
354-
Configurable<float> cfgCrossMaxDist{"cfgCrossMaxDist", 1.0f, "veto: crossed line-line distance below this (cm)"};
353+
Configurable<float> cfgCrossMaxMeeRatio{"cfgCrossMaxMeeRatio", 0.2f, "veto: min(m_ee^cross)/q_inv below this; genuine pairs sit near 0.5, leg swaps near 0"};
355354
Configurable<float> cfgCrossMaxQinvQA{"cfgCrossMaxQinvQA", 0.3f, "fill crossed QA sparses only below this qinv"};
356355
} crosspair;
357356

@@ -752,9 +751,9 @@ struct Photonhbt {
752751
return;
753752
}
754753
for (const auto& sm : {std::string("Pair/same/CrossPair/"), std::string("Pair/mix/CrossPair/")}) {
755-
fRegistryCF.add((sm + "hSparse_Mee_Dist_Qinv").c_str(),
756-
"crossed-hypothesis QA;m_{ee}^{cross} (GeV/c^{2});crossed line distance (cm);q_{inv} (GeV/c)",
757-
kTHnSparseF, {{100, 0.f, 0.1f}, {100, 0.f, 10.f}, {60, 0.f, 0.3f}}, true);
754+
fRegistryCF.add((sm + "hSparse_MeeRatio_dR_Qinv").c_str(),
755+
"crossed-hypothesis QA;min(m_{ee}^{cross})/q_{inv};|R_{1}-R_{2}| (cm);q_{inv} (GeV/c)",
756+
kTHnSparseF, {{100, 0.f, 2.f}, {80, 0.f, 80.f}, {60, 0.f, 0.3f}}, true);
758757
auto h = fRegistryCF.add<TH1>((sm + "hVetoCounter").c_str(), "crossed-pair veto;;pairs", kTH1D, {{2, -0.5f, 1.5f}}, true);
759758
h->GetXaxis()->SetBinLabel(1, "evaluated");
760759
h->GetXaxis()->SetBinLabel(2, "vetoed");
@@ -1307,42 +1306,22 @@ struct Photonhbt {
13071306
return s.u > pairsep.cfgUCut.value;
13081307
}
13091308

1310-
[[nodiscard]] static float lineLineDistance(std::array<float, 3> const& o1, std::array<float, 3> const& d1,
1311-
std::array<float, 3> const& o2, std::array<float, 3> const& d2)
1312-
{
1313-
const std::array<float, 3> w = {o2[0] - o1[0], o2[1] - o1[1], o2[2] - o1[2]};
1314-
const std::array<float, 3> n = {d1[1] * d2[2] - d1[2] * d2[1],
1315-
d1[2] * d2[0] - d1[0] * d2[2],
1316-
d1[0] * d2[1] - d1[1] * d2[0]};
1317-
const float nMag = std::sqrt(n[0] * n[0] + n[1] * n[1] + n[2] * n[2]);
1318-
const float d1Mag2 = d1[0] * d1[0] + d1[1] * d1[1] + d1[2] * d1[2];
1319-
if (nMag < 1e-6f * d1Mag2) { // o2-linter: disable=magic-number (near-parallel: point-to-line distance)
1320-
const float wDotD = (w[0] * d1[0] + w[1] * d1[1] + w[2] * d1[2]) / d1Mag2;
1321-
const std::array<float, 3> perp = {w[0] - wDotD * d1[0], w[1] - wDotD * d1[1], w[2] - wDotD * d1[2]};
1322-
return std::sqrt(perp[0] * perp[0] + perp[1] * perp[1] + perp[2] * perp[2]);
1323-
}
1324-
return std::fabs(w[0] * n[0] + w[1] * n[1] + w[2] * n[2]) / nMag;
1325-
}
1326-
1327-
[[nodiscard]] CrossObs computeCrossObs(PhotonWithLegs const& a, PhotonWithLegs const& b) const
1309+
[[nodiscard]] CrossObs computeCrossObs(PhotonWithLegs const& a, PhotonWithLegs const& b, float qinv) const
13281310
{
13291311
constexpr float kMe = 0.000510999f; // electron mass, GeV/c^2
13301312
CrossObs c;
13311313
auto legVec = [](PhotonWithLegs const& p, int i) {
13321314
return ROOT::Math::PtEtaPhiMVector(p.fLegPt[i], p.fLegEta[i], p.fLegPhi[i], kMe);
13331315
};
1334-
auto legDir = [](PhotonWithLegs const& p, int i) -> std::array<float, 3> {
1335-
return {p.fLegPt[i] * std::cos(p.fLegPhi[i]), p.fLegPt[i] * std::sin(p.fLegPhi[i]),
1336-
p.fLegPt[i] * std::sinh(p.fLegEta[i])};
1337-
};
13381316
// Leg index 0 = e+, 1 = e- (makePhotonWithLegs filling order).
13391317
// Combo 0: a's e+ with b's e-. Combo 1: b's e+ with a's e-.
1340-
for (int combo = 0; combo < 2; ++combo) { // o2-linter: disable=magic-number (combinations of fake photons)
1318+
for (int combo = 0; combo < 2; ++combo) { // o2-linter: disable=magic-number (the two leg-swap combinations)
13411319
PhotonWithLegs const& pPos = (combo == 0) ? a : b;
13421320
PhotonWithLegs const& pEle = (combo == 0) ? b : a;
13431321
c.mee[combo] = static_cast<float>((legVec(pPos, 0) + legVec(pEle, 1)).M());
1344-
c.dist[combo] = lineLineDistance({pPos.fVx, pPos.fVy, pPos.fVz}, legDir(pPos, 0),
1345-
{pEle.fVx, pEle.fVy, pEle.fVz}, legDir(pEle, 1));
1322+
}
1323+
if (qinv > 0.f) {
1324+
c.meeOverQ = std::min(c.mee[0], c.mee[1]) / qinv;
13461325
}
13471326
return c;
13481327
}
@@ -1352,25 +1331,19 @@ struct Photonhbt {
13521331
if (!crosspair.cfgDoCrossPairCut.value) {
13531332
return true;
13541333
}
1355-
for (int i = 0; i < 2; ++i) { // o2-linter: disable=magic-number (combinations of fake photons)
1356-
if (c.mee[i] < crosspair.cfgCrossMaxMee.value && c.dist[i] < crosspair.cfgCrossMaxDist.value) {
1357-
return false;
1358-
}
1359-
}
1360-
return true;
1334+
// A photon-like crossed combination means the pairing is ambiguous.
1335+
return c.meeOverQ > crosspair.cfgCrossMaxMeeRatio.value;
13611336
}
13621337

13631338
template <int ev_id>
1364-
inline void fillCrossPair(CrossObs const& c, float qinv, bool vetoed)
1339+
inline void fillCrossPair(CrossObs const& c, float qinv, float deltaR, bool vetoed)
13651340
{
13661341
constexpr auto dir = (ev_id == 0) ? "Pair/same/CrossPair/" : "Pair/mix/CrossPair/";
13671342
fRegistryCF.fill(HIST(dir) + HIST("hVetoCounter"), vetoed ? 1.0 : 0.0);
13681343
if (qinv > crosspair.cfgCrossMaxQinvQA.value) {
13691344
return;
13701345
}
1371-
for (int i = 0; i < 2; ++i) { // o2-linter: disable=magic-number (combinations of fake photons)
1372-
fRegistryCF.fill(HIST(dir) + HIST("hSparse_Mee_Dist_Qinv"), c.mee[i], c.dist[i], qinv);
1373-
}
1346+
fRegistryCF.fill(HIST(dir) + HIST("hSparse_MeeRatio_dR_Qinv"), c.meeOverQ, deltaR, qinv);
13741347
}
13751348

13761349
[[nodiscard]] float uTrue(TruthGamma const& g1, TruthGamma const& g2) const
@@ -2043,9 +2016,9 @@ struct Photonhbt {
20432016
continue;
20442017
}
20452018
if (crosspair.cfgDoCrossPairQA.value || crosspair.cfgDoCrossPairCut.value) {
2046-
const auto cross = computeCrossObs(pwl1, pwl2);
2019+
const auto cross = computeCrossObs(pwl1, pwl2, obs.qinv);
20472020
const bool vetoed = !passCrossPairVeto(cross);
2048-
fillCrossPair<0>(cross, obs.qinv, vetoed);
2021+
fillCrossPair<0>(cross, obs.qinv, obs.deltaR, vetoed);
20492022
if (vetoed) {
20502023
continue;
20512024
}
@@ -2141,9 +2114,9 @@ struct Photonhbt {
21412114
continue;
21422115
}
21432116
if (crosspair.cfgDoCrossPairQA.value || crosspair.cfgDoCrossPairCut.value) {
2144-
const auto cross = computeCrossObs(g1, g2);
2117+
const auto cross = computeCrossObs(g1, g2, obs.qinv);
21452118
const bool vetoed = !passCrossPairVeto(cross);
2146-
fillCrossPair<1>(cross, obs.qinv, vetoed);
2119+
fillCrossPair<1>(cross, obs.qinv, obs.deltaR, vetoed);
21472120
if (vetoed) {
21482121
continue;
21492122
}
@@ -2271,9 +2244,9 @@ struct Photonhbt {
22712244
continue;
22722245
}
22732246
if (crosspair.cfgDoCrossPairQA.value || crosspair.cfgDoCrossPairCut.value) {
2274-
const auto cross = computeCrossObs(pwl1, pwl2);
2247+
const auto cross = computeCrossObs(pwl1, pwl2, obs.qinv);
22752248
const bool vetoed = !passCrossPairVeto(cross);
2276-
fillCrossPair<0>(cross, obs.qinv, vetoed);
2249+
fillCrossPair<0>(cross, obs.qinv, obs.deltaR, vetoed);
22772250
if (vetoed) {
22782251
continue;
22792252
}
@@ -2422,9 +2395,9 @@ struct Photonhbt {
24222395
continue;
24232396
}
24242397
if (crosspair.cfgDoCrossPairQA.value || crosspair.cfgDoCrossPairCut.value) {
2425-
const auto cross = computeCrossObs(g1, g2);
2398+
const auto cross = computeCrossObs(g1, g2, obs.qinv);
24262399
const bool vetoed = !passCrossPairVeto(cross);
2427-
fillCrossPair<1>(cross, obs.qinv, vetoed);
2400+
fillCrossPair<1>(cross, obs.qinv, obs.deltaR, vetoed);
24282401
if (vetoed) {
24292402
continue;
24302403
}
@@ -2735,7 +2708,7 @@ struct Photonhbt {
27352708
fRegistryTruthMC.fill(HIST("MC/TruthAO2D/hQinvVsKt_all4LegsThisColl"), kt, qinv_true);
27362709
fRegistryTruthMC.fill(HIST("MC/TruthAO2D/hDEtaDPhi_all4LegsThisColl"), deta, dphi);
27372710
}
2738-
if (g1Sel && g2Sel) {
2711+
if (g1Built && g2Built) {
27392712
fRegistryTruthMC.fill(HIST("MC/TruthAO2D/hSparse_DEtaDPhi_qinv_bothPhotonsBuilt"), deta, dphi, qinv_true);
27402713
fRegistryTruthMC.fill(HIST("MC/TruthAO2D/hSparse_DEtaDPhi_kT_bothPhotonsBuilt"), deta, dphi, kt);
27412714
fRegistryTruthMC.fill(HIST("MC/TruthAO2D/hQinvVsKt_bothPhotonsBuilt"), kt, qinv_true);

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