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MTD reconstruction: propagation of track time of flight uncertainty to vertex reconstruction #44562

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merged 6 commits into from
Apr 12, 2024
Merged

MTD reconstruction: propagation of track time of flight uncertainty to vertex reconstruction #44562

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52f2b56
Propagated track sigma(TOF) on MTD hit-to-track matching, final track…
noepalm Mar 20, 2024
c74aa70
Updated array from C-style array to std::array
noepalm Mar 26, 2024
d69c2bd
Added kMixd calculation strategy for sigma(TOF), set as default in ca…
noepalm Mar 26, 2024
3d658f8
Code checks && format
noepalm Mar 26, 2024
6d4465f
Added dterror2 to track TOF PID info struct and used it to replace oc…
noepalm Apr 8, 2024
d293345
Code checks and format
noepalm Apr 9, 2024
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41 changes: 32 additions & 9 deletions RecoMTD/TimingIDTools/plugins/TOFPIDProducer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,9 @@ class TOFPIDProducer : public edm::stream::EDProducer<> {
edm::EDGetTokenT<edm::ValueMap<float>> sigmatmtdToken_;
edm::EDGetTokenT<edm::ValueMap<float>> tofkToken_;
edm::EDGetTokenT<edm::ValueMap<float>> tofpToken_;
edm::EDGetTokenT<edm::ValueMap<float>> sigmatofpiToken_;
edm::EDGetTokenT<edm::ValueMap<float>> sigmatofkToken_;
edm::EDGetTokenT<edm::ValueMap<float>> sigmatofpToken_;
edm::EDGetTokenT<reco::VertexCollection> vtxsToken_;
edm::EDGetTokenT<edm::ValueMap<float>> trackMTDTimeQualityToken_;
const double vtxMaxSigmaT_;
Expand All @@ -71,6 +74,9 @@ TOFPIDProducer::TOFPIDProducer(const ParameterSet& iConfig)
sigmatmtdToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("sigmatmtdSrc"))),
tofkToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("tofkSrc"))),
tofpToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("tofpSrc"))),
sigmatofpiToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("sigmatofpiSrc"))),
sigmatofkToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("sigmatofkSrc"))),
sigmatofpToken_(consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("sigmatofpSrc"))),
vtxsToken_(consumes<reco::VertexCollection>(iConfig.getParameter<edm::InputTag>("vtxsSrc"))),
trackMTDTimeQualityToken_(
consumes<edm::ValueMap<float>>(iConfig.getParameter<edm::InputTag>("trackMTDTimeQualityVMapTag"))),
Expand Down Expand Up @@ -110,6 +116,12 @@ void TOFPIDProducer::fillDescriptions(edm::ConfigurationDescriptions& descriptio
->setComment("Input ValueMap for track tof as kaon");
desc.add<edm::InputTag>("tofpSrc", edm::InputTag("trackExtenderWithMTD:generalTrackTofP"))
->setComment("Input ValueMap for track tof as proton");
desc.add<edm::InputTag>("sigmatofpiSrc", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofPi"))
->setComment("Input ValueMap for track sigma(tof) as pion");
desc.add<edm::InputTag>("sigmatofkSrc", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofK"))
->setComment("Input ValueMap for track sigma(tof) as kaon");
desc.add<edm::InputTag>("sigmatofpSrc", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofP"))
->setComment("Input ValueMap for track sigma(tof) as proton");
desc.add<edm::InputTag>("vtxsSrc", edm::InputTag("unsortedOfflinePrimaryVertices4DwithPID"))
->setComment("Input primary vertex collection");
desc.add<edm::InputTag>("trackMTDTimeQualityVMapTag", edm::InputTag("mtdTrackQualityMVA:mtdQualMVA"))
Expand Down Expand Up @@ -163,6 +175,12 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {

const auto& tofpIn = ev.get(tofpToken_);

const auto& sigmatofpiIn = ev.get(sigmatofpiToken_);

const auto& sigmatofkIn = ev.get(sigmatofkToken_);

const auto& sigmatofpIn = ev.get(sigmatofpToken_);

const auto& vtxs = ev.get(vtxsToken_);

const auto& trackMVAQualIn = ev.get(trackMTDTimeQualityToken_);
Expand All @@ -185,6 +203,9 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {
float sigmat0safe = sigmat0In[trackref];
float sigmatmtd = (sigmatmtdIn[trackref] > 0. && fixedT0Error_ > 0.) ? fixedT0Error_ : sigmatmtdIn[trackref];
float sigmat0 = sigmatmtd;
float sigmatofpi = sigmatofpiIn[trackref];
float sigmatofk = sigmatofkIn[trackref];
float sigmatofp = sigmatofpIn[trackref];

float prob_pi = -1.;
float prob_k = -1.;
Expand All @@ -194,7 +215,9 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {

if (sigmat0 > 0. && (!MVASel_ || (MVASel_ && trackMVAQual >= minTrackTimeQuality_))) {
double rsigmazsq = 1. / track.dzError() / track.dzError();
double rsigmat = 1. / sigmatmtd;
std::array<double, 3> rsigmat = {{1. / std::sqrt(sigmatmtd * sigmatmtd + sigmatofpi * sigmatofpi),
1. / std::sqrt(sigmatmtd * sigmatmtd + sigmatofk * sigmatofk),
1. / std::sqrt(sigmatmtd * sigmatmtd + sigmatofp * sigmatofp)}};

//find associated vertex
int vtxidx = -1;
Expand All @@ -217,7 +240,7 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {
}
if (vtx.tError() > 0. && vtx.tError() < vtxMaxSigmaT_) {
double dt = std::abs(t0 - vtx.t());
double dtsig = dt * rsigmat;
double dtsig = dt * rsigmat[0]; //pion hp. uncertainty
double chisq = dz * dz * rsigmazsq + dtsig * dtsig;
if (dz < maxDz_ && dtsig < maxDtSignificance_ && chisq < minchisq) {
minchisq = chisq;
Expand Down Expand Up @@ -245,15 +268,15 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {
const reco::Vertex& vtxnom = vtxs[vtxidx];
double dznom = std::abs(track.dz(vtxnom.position()));
double dtnom = std::abs(t0 - vtxnom.t());
double dtsignom = dtnom * rsigmat;
double dtsignom = dtnom * rsigmat[0];
double chisqnom = dznom * dznom * rsigmazsq + dtsignom * dtsignom;

//recompute t0 for alternate mass hypotheses
double t0_best = t0;

//reliable match, revert to raw mtd time uncertainty
//reliable match, revert to raw mtd time uncertainty + tof uncertainty for pion hp
if (dtsignom < maxDtSignificance_) {
sigmat0safe = sigmatmtd;
sigmat0safe = 1. / rsigmat[0];
}

double tmtd = tmtdIn[trackref];
Expand Down Expand Up @@ -284,15 +307,15 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {
double chisqdz = dz * dz * rsigmazsq;

double dt_k = std::abs(t0_k - vtx.t());
double dtsig_k = dt_k * rsigmat;
double dtsig_k = dt_k * rsigmat[1];
double chisq_k = chisqdz + dtsig_k * dtsig_k;

if (dtsig_k < maxDtSignificance_ && chisq_k < chisqmin_k) {
chisqmin_k = chisq_k;
}

double dt_p = std::abs(t0_p - vtx.t());
double dtsig_p = dt_p * rsigmat;
double dtsig_p = dt_p * rsigmat[2];
double chisq_p = chisqdz + dtsig_p * dtsig_p;

if (dtsig_p < maxDtSignificance_ && chisq_p < chisqmin_p) {
Expand All @@ -303,13 +326,13 @@ void TOFPIDProducer::produce(edm::Event& ev, const edm::EventSetup& es) {
chisqmin = chisq_k;
t0_best = t0_k;
t0safe = t0_k;
sigmat0safe = sigmatmtd;
sigmat0safe = 1. / rsigmat[1];
}
if (dtsig_p < maxDtSignificance_ && chisq_p < chisqmin) {
chisqmin = chisq_p;
t0_best = t0_p;
t0safe = t0_p;
sigmat0safe = sigmatmtd;
sigmat0safe = 1. / rsigmat[2];
}
}

Expand Down
23 changes: 17 additions & 6 deletions RecoMTD/TrackExtender/plugins/TrackExtenderWithMTD.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,7 @@ namespace {
};

enum class TofCalc { kCost = 1, kSegm = 2, kMixd = 3 };
enum class SigmaTofCalc { kCost = 1, kSegm = 2 };
enum class SigmaTofCalc { kCost = 1, kSegm = 2, kMixd = 3 };

const TrackTofPidInfo computeTrackTofPidInfo(float magp2,
float length,
Expand Down Expand Up @@ -279,6 +279,11 @@ namespace {
case SigmaTofCalc::kSegm:
res = trs.computeSigmaTof(mass_inv2);
break;
case SigmaTofCalc::kMixd:
float res1 = tofpid.pathlength * c_inv * trs.segmentSigmaMom_[trs.nSegment_ - 1] /
(magp2 * sqrt(magp2 + 1 / mass_inv2) * mass_inv2);
float res2 = trs.computeSigmaTof(mass_inv2);
res = sqrt(res1 * res1 + res2 * res2 + 2 * res1 * res2);
}

return res;
Expand Down Expand Up @@ -306,6 +311,9 @@ namespace {
tofpid.dterror =
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Minor comment, but it seems like you take the sqrt here, only to square this term several times below. Consider simply using the square to begin with.

sqrt(tofpid.dterror * tofpid.dterror + (tofpid.dt_p - tofpid.dt_pi) * (tofpid.dt_p - tofpid.dt_pi));
tofpid.betaerror = tofpid.beta_p - tofpid.beta_pi;
} else {
// only add sigma(TOF) if not considering mass hp. uncertainty
tofpid.dterror = sqrt(tofpid.dterror * tofpid.dterror + tofpid.sigma_dt_pi * tofpid.sigma_dt_pi);
}

tofpid.dtchi2 = (tofpid.dt * tofpid.dt) / (tofpid.dterror * tofpid.dterror);
Expand All @@ -321,10 +329,12 @@ namespace {
if (!addPIDError) {
//*TODO* deal with heavier nucleons and/or BSM case here?
float chi2_pi = tofpid.dtchi2;
float chi2_k =
(tofpid.tmtd - tofpid.dt_k - t_vtx) * (tofpid.tmtd - tofpid.dt_k - t_vtx) / (tofpid.dterror * tofpid.dterror);
float chi2_p =
(tofpid.tmtd - tofpid.dt_p - t_vtx) * (tofpid.tmtd - tofpid.dt_p - t_vtx) / (tofpid.dterror * tofpid.dterror);
float chi2_k = (tofpid.tmtd - tofpid.dt_k - t_vtx) * (tofpid.tmtd - tofpid.dt_k - t_vtx) /
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(tofpid.dterror * tofpid.dterror - tofpid.sigma_dt_pi * tofpid.sigma_dt_pi +
tofpid.sigma_dt_k * tofpid.sigma_dt_k);
float chi2_p = (tofpid.tmtd - tofpid.dt_p - t_vtx) * (tofpid.tmtd - tofpid.dt_p - t_vtx) /
(tofpid.dterror * tofpid.dterror - tofpid.sigma_dt_pi * tofpid.sigma_dt_pi +
tofpid.sigma_dt_p * tofpid.sigma_dt_p);

float rawprob_pi = exp(-0.5f * chi2_pi);
float rawprob_k = exp(-0.5f * chi2_k);
Expand Down Expand Up @@ -1107,7 +1117,8 @@ namespace {
t_vtx,
t_vtx_err, //put vtx error by hand for the moment
false,
TofCalc::kMixd);
TofCalc::kMixd,
SigmaTofCalc::kMixd);
MTDHitMatchingInfo mi;
mi.hit = &hit;
mi.estChi2 = est.second;
Expand Down
8 changes: 7 additions & 1 deletion RecoVertex/PrimaryVertexProducer/interface/VertexTimeAlgorithmFromTracksPID.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ class VertexTimeAlgorithmFromTracksPID : public VertexTimeAlgorithmBase {
protected:
struct TrackInfo {
double trkWeight;
double trkTimeError;
double trkTimeErrorHyp[3];
double trkTimeHyp[3];
};

Expand All @@ -31,6 +31,9 @@ class VertexTimeAlgorithmFromTracksPID : public VertexTimeAlgorithmBase {
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDTofPiToken_;
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDTofKToken_;
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDTofPToken_;
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDSigmaTofPiToken_;
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDSigmaTofKToken_;
edm::EDGetTokenT<edm::ValueMap<float>> const trackMTDSigmaTofPToken_;

double const minTrackVtxWeight_;
double const minTrackTimeQuality_;
Expand All @@ -46,6 +49,9 @@ class VertexTimeAlgorithmFromTracksPID : public VertexTimeAlgorithmBase {
edm::ValueMap<float> trackMTDTofPi_;
edm::ValueMap<float> trackMTDTofK_;
edm::ValueMap<float> trackMTDTofP_;
edm::ValueMap<float> trackMTDSigmaTofPi_;
edm::ValueMap<float> trackMTDSigmaTofK_;
edm::ValueMap<float> trackMTDSigmaTofP_;
};

#endif
49 changes: 38 additions & 11 deletions RecoVertex/PrimaryVertexProducer/src/VertexTimeAlgorithmFromTracksPID.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,9 @@ VertexTimeAlgorithmFromTracksPID::VertexTimeAlgorithmFromTracksPID(edm::Paramete
trackMTDTofPiToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDTofPiVMapTag"))),
trackMTDTofKToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDTofKVMapTag"))),
trackMTDTofPToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDTofPVMapTag"))),
trackMTDSigmaTofPiToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDSigmaTofPiVMapTag"))),
trackMTDSigmaTofKToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDSigmaTofKVMapTag"))),
trackMTDSigmaTofPToken_(iCC.consumes(iConfig.getParameter<edm::InputTag>("trackMTDSigmaTofPVMapTag"))),
minTrackVtxWeight_(iConfig.getParameter<double>("minTrackVtxWeight")),
minTrackTimeQuality_(iConfig.getParameter<double>("minTrackTimeQuality")),
probPion_(iConfig.getParameter<double>("probPion")),
Expand All @@ -46,6 +49,12 @@ void VertexTimeAlgorithmFromTracksPID::fillPSetDescription(edm::ParameterSetDesc
->setComment("Input ValueMap for track tof as kaon");
iDesc.add<edm::InputTag>("trackMTDTofPVMapTag", edm::InputTag("trackExtenderWithMTD:generalTrackTofP"))
->setComment("Input ValueMap for track tof as proton");
iDesc.add<edm::InputTag>("trackMTDSigmaTofPiVMapTag", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofPi"))
->setComment("Input ValueMap for track tof uncertainty as pion");
iDesc.add<edm::InputTag>("trackMTDSigmaTofKVMapTag", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofK"))
->setComment("Input ValueMap for track tof uncertainty as kaon");
iDesc.add<edm::InputTag>("trackMTDSigmaTofPVMapTag", edm::InputTag("trackExtenderWithMTD:generalTrackSigmaTofP"))
->setComment("Input ValueMap for track tof uncertainty as proton");

iDesc.add<double>("minTrackVtxWeight", 0.5)->setComment("Minimum track weight");
iDesc.add<double>("minTrackTimeQuality", 0.8)->setComment("Minimum MVA Quality selection on tracks");
Expand All @@ -66,6 +75,9 @@ void VertexTimeAlgorithmFromTracksPID::setEvent(edm::Event& iEvent, edm::EventSe
trackMTDTofPi_ = iEvent.get(trackMTDTofPiToken_);
trackMTDTofK_ = iEvent.get(trackMTDTofKToken_);
trackMTDTofP_ = iEvent.get(trackMTDTofPToken_);
trackMTDSigmaTofPi_ = iEvent.get(trackMTDSigmaTofPiToken_);
trackMTDSigmaTofK_ = iEvent.get(trackMTDSigmaTofKToken_);
trackMTDSigmaTofP_ = iEvent.get(trackMTDSigmaTofPToken_);
}

bool VertexTimeAlgorithmFromTracksPID::vertexTime(float& vtxTime,
Expand Down Expand Up @@ -102,23 +114,36 @@ bool VertexTimeAlgorithmFromTracksPID::vertexTime(float& vtxTime,
auto& trkInfo = v_trackInfo.back();

trkInfo.trkWeight = trkWeight;
trkInfo.trkTimeError = trkTimeError;
trkInfo.trkTimeErrorHyp[0] =
std::sqrt(trkTimeError * trkTimeError +
trackMTDSigmaTofPi_[trk.trackBaseRef()] * trackMTDSigmaTofPi_[trk.trackBaseRef()]);
trkInfo.trkTimeErrorHyp[1] =
std::sqrt(trkTimeError * trkTimeError +
trackMTDSigmaTofK_[trk.trackBaseRef()] * trackMTDSigmaTofK_[trk.trackBaseRef()]);
trkInfo.trkTimeErrorHyp[2] =
std::sqrt(trkTimeError * trkTimeError +
trackMTDSigmaTofP_[trk.trackBaseRef()] * trackMTDSigmaTofP_[trk.trackBaseRef()]);

trkInfo.trkTimeHyp[0] = trkTime - trackMTDTofPi_[trk.trackBaseRef()];
trkInfo.trkTimeHyp[1] = trkTime - trackMTDTofK_[trk.trackBaseRef()];
trkInfo.trkTimeHyp[2] = trkTime - trackMTDTofP_[trk.trackBaseRef()];

auto const wgt = trkWeight / (trkTimeError * trkTimeError);
wsum += wgt;
double const wgt[3] = {trkWeight / (trkInfo.trkTimeErrorHyp[0] * trkInfo.trkTimeErrorHyp[0]),
trkWeight / (trkInfo.trkTimeErrorHyp[1] * trkInfo.trkTimeErrorHyp[1]),
trkWeight / (trkInfo.trkTimeErrorHyp[2] * trkInfo.trkTimeErrorHyp[2])};

for (uint j = 0; j < 3; ++j) {
tsum += wgt * trkInfo.trkTimeHyp[j] * a[j];
wsum += wgt[j] * a[j];
tsum += wgt[j] * a[j] * trkInfo.trkTimeHyp[j];
}

LOG << "vertexTimeFromTracks: track"
<< " pt=" << trk.track().pt() << " eta=" << trk.track().eta() << " phi=" << trk.track().phi()
<< " vtxWeight=" << trkWeight << " time=" << trkTime << " timeError=" << trkTimeError
<< " timeQuality=" << trkTimeQuality << " timeHyp[pion]=" << trkInfo.trkTimeHyp[0]
<< " timeHyp[kaon]=" << trkInfo.trkTimeHyp[1] << " timeHyp[proton]=" << trkInfo.trkTimeHyp[2];
<< " timeQuality=" << trkTimeQuality << " timeHyp[pion]=" << trkInfo.trkTimeHyp[0] << " +/- "
<< trkInfo.trkTimeErrorHyp[0] << " timeHyp[kaon]=" << trkInfo.trkTimeHyp[1] << " +/- "
<< trkInfo.trkTimeErrorHyp[1] << " timeHyp[proton]=" << trkInfo.trkTimeHyp[2] << " +/- "
<< trkInfo.trkTimeErrorHyp[2];
}
}
}
Expand All @@ -132,27 +157,29 @@ bool VertexTimeAlgorithmFromTracksPID::vertexTime(float& vtxTime,
w2sum = 0;

for (auto const& trkInfo : v_trackInfo) {
double dt = trkInfo.trkTimeError;
double dt[3] = {trkInfo.trkTimeErrorHyp[0], trkInfo.trkTimeErrorHyp[1], trkInfo.trkTimeErrorHyp[2]};
double e[3] = {0, 0, 0};
const double cut_off = 4.5;
double Z = vdt::fast_exp(
-beta * cut_off); // outlier rejection term Z_0 = exp(-beta * cut_off) = exp(-beta * 0.5 * 3 * 3)

for (unsigned int j = 0; j < 3; j++) {
auto const tpull = (trkInfo.trkTimeHyp[j] - t0) / dt;
auto const tpull = (trkInfo.trkTimeHyp[j] - t0) / dt[j];
e[j] = vdt::fast_exp(-0.5 * beta * tpull * tpull);
Z += a[j] * e[j];
}

double wsum_trk = 0;
double wsum_trk = 0, wsum_sigma_trk = 0;
for (uint j = 0; j < 3; j++) {
double wt = a[j] * e[j] / Z;
double w = wt * trkInfo.trkWeight / (dt * dt);
double w = wt * trkInfo.trkWeight / (dt[j] * dt[j]);
wsum_trk += w;
wsum_sigma_trk += w * dt[j];
tsum += w * trkInfo.trkTimeHyp[j];
}

wsum += wsum_trk;
w2sum += wsum_trk * wsum_trk * (dt * dt) / trkInfo.trkWeight;
w2sum += wsum_sigma_trk * wsum_sigma_trk;
}

if (wsum < 1e-10) {
Expand Down
7 changes: 1 addition & 6 deletions RecoVertex/PrimaryVertexProducer/src/VertexTimeAlgorithmLegacy4D.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,6 @@ bool VertexTimeAlgorithmLegacy4D::vertexTime(float& vtxTime, float& vtxTimeError
double sumwt = 0.;
double sumwt2 = 0.;
double sumw = 0.;
double vartime = 0.;

for (const auto& trk : vtx.originalTracks()) {
const double time = trk.timeExt();
Expand All @@ -43,12 +42,8 @@ bool VertexTimeAlgorithmLegacy4D::vertexTime(float& vtxTime, float& vtxTimeError
}

if (sumw > 0) {
double sumsq = sumwt2 - sumwt * sumwt / sumw;
double chisq = num_track > 1 ? sumsq / double(num_track - 1) : sumsq / double(num_track);
vartime = chisq / sumw;

vtxTime = sumwt / sumw;
vtxTimeError = sqrt(vartime);
vtxTimeError = 1 / sqrt(sumw);
return true;
}

Expand Down