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[PWGLF] Lambda local polarization induced by jet in pp collision 13.6 TeV #11529

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romainschotter merged 2 commits into from
Jun 10, 2025
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[PWGLF] Lambda local polarization induced by jet in pp collision 13.6 TeV #11529

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15071832337 Jun 10, 2025
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Update lambdaJetpolarization.cxx
15071832337 Jun 10, 2025
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61 changes: 24 additions & 37 deletions PWGLF/Tasks/Strangeness/lambdaJetpolarization.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
///

/// \author Youpeng Su (yousu@cern.ch)
#include <iostream>

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[include-iostream] 

Do not include iostream. Use O2 logging instead.
#include <string>
#include <vector>
#include <cmath>
Expand All @@ -29,6 +29,9 @@
#include <TMatrixD.h>
#include "TProfile2D.h"
#include "PWGLF/DataModel/lambdaJetpolarization.h"
#include "Math/Vector3D.h"
#include "Math/Vector4D.h"
#include "Math/GenVector/Boost.h"

#include <fastjet/ClusterSequence.hh>
#include <fastjet/ClusterSequenceArea.hh>
Expand Down Expand Up @@ -351,11 +354,13 @@
}
double massPr = o2::constants::physics::MassProton;
double massLambda = o2::constants::physics::MassLambda;
double massPi = o2::constants::physics::MassPionCharged;
ROOT::Math::PxPyPzMVector ProtonVec, PionVec, LambdaVec, ProtonBoostedVec, LambdaBoostedVec;

TMatrixD LorentzTransInV0frame(double ELambda, double Lambdapx, double Lambdapy, double Lambdapz)
{
double PLambda = sqrt(Lambdapx * Lambdapx + Lambdapy * Lambdapy + Lambdapz * Lambdapz);

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[std-prefix] 

Use std:: prefix for names from the std namespace.
double LambdaMass = sqrt(ELambda * ELambda - PLambda * PLambda);

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[std-prefix] 

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double Alpha = 1 / (LambdaMass * (ELambda + LambdaMass));
TMatrixD matrixLabToLambda(4, 4);
matrixLabToLambda(0, 0) = ELambda / LambdaMass;
Expand Down Expand Up @@ -422,10 +427,10 @@
registry.fill(HIST("V0protonpxInLab"), candidate.v0protonpx());
registry.fill(HIST("V0protonpyInLab"), candidate.v0protonpy());
registry.fill(HIST("V0protonpzInLab"), candidate.v0protonpz());
double protonsinPhiInLab = candidate.v0protonpy() / sqrt(candidate.v0protonpx() * candidate.v0protonpx() + candidate.v0protonpy() * candidate.v0protonpy());

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[std-prefix] 

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registry.fill(HIST("V0protonphiInLab"), protonsinPhiInLab);
double PLambda = sqrt(candidate.v0px() * candidate.v0px() + candidate.v0py() * candidate.v0py() + candidate.v0pz() * candidate.v0pz());

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[std-prefix] 

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double ELambda = sqrt(candidate.v0Lambdamass() * candidate.v0Lambdamass() + PLambda * PLambda);

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[std-prefix] 

Use std:: prefix for names from the std namespace.
TMatrixD pLabV0(4, 1);
pLabV0(0, 0) = ELambda;
pLabV0(1, 0) = candidate.v0px();
Expand All @@ -438,17 +443,17 @@
registry.fill(HIST("V0pzInRest_frame"), V0InV0(3, 0));
}
for (auto& candidate : myv0s) {
double PLambda = sqrt(candidate.v0px() * candidate.v0px() + candidate.v0py() * candidate.v0py() + candidate.v0pz() * candidate.v0pz());

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[std-prefix] 

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double ELambda = sqrt(candidate.v0Lambdamass() * candidate.v0Lambdamass() + PLambda * PLambda);

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[std-prefix] 

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TMatrixD pLabproton(4, 1);
double protonE = sqrt(massPr * massPr + candidate.v0protonpx() * candidate.v0protonpx() + candidate.v0protonpy() * candidate.v0protonpy() + candidate.v0protonpz() * candidate.v0protonpz());

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[std-prefix] 

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pLabproton(0, 0) = protonE;
pLabproton(1, 0) = candidate.v0protonpx();
pLabproton(2, 0) = candidate.v0protonpy();
pLabproton(3, 0) = candidate.v0protonpz();
TMatrixD protonInV0(4, 1);
protonInV0 = LorentzTransInV0frame(ELambda, candidate.v0px(), candidate.v0py(), candidate.v0pz()) * pLabproton;
double protonMassInV0 = sqrt(protonInV0(0, 0) * protonInV0(0, 0) - protonInV0(1, 0) * protonInV0(1, 0) - protonInV0(2, 0) * protonInV0(2, 0) - protonInV0(3, 0) * protonInV0(3, 0));

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[std-prefix] 

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registry.fill(HIST("V0protonMassInRest_frame"), protonMassInV0);
registry.fill(HIST("V0protonpxInRest_frame"), protonInV0(1, 0));
registry.fill(HIST("V0protonpyInRest_frame"), protonInV0(2, 0));
Expand Down Expand Up @@ -1233,32 +1238,20 @@
if (passedLambdaSelection(v0, pos, neg) && ctauLambda < CtauLambda && ifpasslambda) {
V0NumbersPerEventsel++;
registryLongitudinalPolarization.fill(HIST("hMassVsPtLambda"), v0.pt(), v0.mLambda());
double PLambda = sqrt(v0.px() * v0.px() + v0.py() * v0.py() + v0.pz() * v0.pz());
double ELambda = sqrt(v0.mLambda() * v0.mLambda() + PLambda * PLambda);
double protonE = sqrt(massPr * massPr + pos.px() * pos.px() + pos.py() * pos.py() + pos.pz() * pos.pz());
TMatrixD pLabV0(4, 1);
pLabV0(0, 0) = ELambda;
pLabV0(1, 0) = v0.px();
pLabV0(2, 0) = v0.py();
pLabV0(3, 0) = v0.pz();

TMatrixD pLabproton(4, 1);
pLabproton(0, 0) = protonE;
pLabproton(1, 0) = pos.px();
pLabproton(2, 0) = pos.py();
pLabproton(3, 0) = pos.pz();
ProtonVec = ROOT::Math::PxPyPzMVector(v0.pxpos(), v0.pypos(), v0.pzpos(), massPr);
PionVec = ROOT::Math::PxPyPzMVector(v0.pxneg(), v0.pyneg(), v0.pzneg(), massPi);
LambdaVec = ProtonVec + PionVec;
LambdaVec.SetM(massLambda);
ROOT::Math::Boost boost{LambdaVec.BoostToCM()};
ProtonBoostedVec = boost(ProtonVec);
LambdaBoostedVec = boost(LambdaVec);

TMatrixD V0InV0(4, 1);
V0InV0 = LorentzTransInV0frame(ELambda, v0.px(), v0.py(), v0.pz()) * pLabV0;
registryLongitudinalPolarization.fill(HIST("V0pxInRest_frame"), V0InV0(1, 0));
registryLongitudinalPolarization.fill(HIST("V0pyInRest_frame"), V0InV0(2, 0));
registryLongitudinalPolarization.fill(HIST("V0pzInRest_frame"), V0InV0(3, 0));
registryLongitudinalPolarization.fill(HIST("V0pxInRest_frame"), LambdaBoostedVec.Px());
registryLongitudinalPolarization.fill(HIST("V0pyInRest_frame"), LambdaBoostedVec.Py());
registryLongitudinalPolarization.fill(HIST("V0pzInRest_frame"), LambdaBoostedVec.Pz());

TMatrixD protonInV0(4, 1);
protonInV0 = LorentzTransInV0frame(ELambda, v0.px(), v0.py(), v0.pz()) * pLabproton;
double protonPInV0 = sqrt(protonInV0(1, 0) * protonInV0(1, 0) + protonInV0(2, 0) * protonInV0(2, 0) + protonInV0(3, 0) * protonInV0(3, 0));

double protonCosThetainV0 = protonInV0(3, 0) / protonPInV0;
double protonCosThetainV0 = ProtonBoostedVec.Pz() / ProtonBoostedVec.P();

registryLongitudinalPolarization.fill(HIST("hprotoncosthetainV0"), protonCosThetainV0);
registryLongitudinalPolarization.fill(HIST("hprotoncosSquarethetainV0"), protonCosThetainV0 * protonCosThetainV0);
Expand All @@ -1272,21 +1265,15 @@
if (passedAntiLambdaSelection(v0, pos, neg) && ctauAntiLambda < CtauLambda && ifpasslambda) {
registryLongitudinalPolarization.fill(HIST("hMassVsPtAntiLambda"), v0.pt(), v0.mAntiLambda());

double PLambda = sqrt(v0.px() * v0.px() + v0.py() * v0.py() + v0.pz() * v0.pz());
double ELambda = sqrt(v0.mAntiLambda() * v0.mAntiLambda() + PLambda * PLambda);
double protonE = sqrt(massPr * massPr + neg.px() * neg.px() + neg.py() * neg.py() + neg.pz() * neg.pz());

TMatrixD pLabproton(4, 1);
pLabproton(0, 0) = protonE;
pLabproton(1, 0) = neg.px();
pLabproton(2, 0) = neg.py();
pLabproton(3, 0) = neg.pz();

TMatrixD protonInV0(4, 1);
protonInV0 = LorentzTransInV0frame(ELambda, v0.px(), v0.py(), v0.pz()) * pLabproton;
double protonPInV0 = sqrt(protonInV0(1, 0) * protonInV0(1, 0) + protonInV0(2, 0) * protonInV0(2, 0) + protonInV0(3, 0) * protonInV0(3, 0));
ProtonVec = ROOT::Math::PxPyPzMVector(v0.pxneg(), v0.pyneg(), v0.pzneg(), massPr);
PionVec = ROOT::Math::PxPyPzMVector(v0.pxpos(), v0.pypos(), v0.pzpos(), massPi);
LambdaVec = ProtonVec + PionVec;
LambdaVec.SetM(massLambda);
ROOT::Math::Boost boost{LambdaVec.BoostToCM()};
ProtonBoostedVec = boost(ProtonVec);
LambdaBoostedVec = boost(LambdaVec);

double protonCosThetainV0 = protonInV0(3, 0) / protonPInV0;
double protonCosThetainV0 = ProtonBoostedVec.Pz() / ProtonBoostedVec.P();

registryLongitudinalPolarization.fill(HIST("hantiprotoncosthetainV0"), protonCosThetainV0);
registryLongitudinalPolarization.fill(HIST("hantiprotoncosSquarethetainV0"), protonCosThetainV0 * protonCosThetainV0);
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