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[PWGLF] Add rapidity cut #16550

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[PWGLF] Add rapidity cut #16550

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da480c0
[PWGLF] Add rapidity cut
alcaliva Jun 6, 2026
813be26
fix whitespace
alcaliva Jun 6, 2026
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22 changes: 15 additions & 7 deletions PWGLF/TableProducer/Nuspex/coalescenceTreeProducer.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,8 @@ using namespace o2::framework::expressions;
using namespace o2::constants::physics;
using namespace o2::constants::math;

constexpr double massHypertriton = 2.99116;

// Lightweight particle container
struct ReducedParticle {
int64_t idPart = 0;
Expand All @@ -84,8 +86,9 @@ struct CoalescenceTreeProducer {
// Configurable analysis parameters
Configurable<float> zVtxMax{"zVtxMax", 10.f, "Maximum |z vertex| in cm"};
Configurable<float> etaMax{"etaMax", 1.5f, "Maximum |eta| for generated particles"};
Configurable<float> pRhoMax{"pRhoMax", 1.0f, "Maximum Jacobi p_rho in GeV/c"};
Configurable<float> pLambdaMax{"pLambdaMax", 1.0f, "Maximum Jacobi p_lambda in GeV/c"};
Configurable<float> pRhoMax{"pRhoMax", 0.5f, "Maximum Jacobi p_rho in GeV/c"};
Configurable<float> pLambdaMax{"pLambdaMax", 0.5f, "Maximum Jacobi p_lambda in GeV/c"};
Configurable<float> yMax{"yMax", 0.5f, "Maximum rapidity"};

// Output tree storing bound-state candidates
OutputObj<TTree> treeBoundState{"treeBoundState", OutputObjHandlingPolicy::AnalysisObject};
Expand Down Expand Up @@ -173,7 +176,7 @@ struct CoalescenceTreeProducer {

// Apply a momentum-space skim using Jacobi momenta in the candidate rest frame
template <typename ReducedPart>
bool passThreeBodySkim(const ReducedPart& b1, const ReducedPart& b2, const ReducedPart& b3)
bool passThreeBodySkim(const ReducedPart& b1, const ReducedPart& b2, const ReducedPart& b3, double massBoundState)
{
// Constituent masses from PDG codes
double m1 = massFromPdg(b1.pdgPart);
Expand All @@ -189,10 +192,15 @@ struct CoalescenceTreeProducer {
auto p4B3 = ROOT::Math::PxPyPzMVector{b3.pxPart, b3.pyPart, b3.pzPart, m3};

// Candidate four-momentum
auto candidate = p4B1 + p4B2 + p4B3;
ROOT::Math::PxPyPzMVector p4Candidate(p4B1.Px() + p4B2.Px() + p4B3.Px(), p4B1.Py() + p4B2.Py() + p4B3.Py(), p4B1.Pz() + p4B2.Pz() + p4B3.Pz(), massBoundState);

// Apply rapidity selection
if (std::abs(p4Candidate.Rapidity()) > yMax) {
return false;
}

// Boost to the candidate rest frame
auto betaCandidate = candidate.BoostToCM();
auto betaCandidate = p4Candidate.BoostToCM();
ROOT::Math::Boost boostToRest(betaCandidate);

// Constituent momenta in the candidate rest frame
Expand Down Expand Up @@ -298,7 +306,7 @@ struct CoalescenceTreeProducer {
// Skip mixed-sign combinations
if (!isMatter && !isAntimatter)
continue;
const bool passSkim = passThreeBodySkim(proton, neutron, lambda);
const bool passSkim = passThreeBodySkim(proton, neutron, lambda, massHypertriton);

if (isMatter && passSkim)
nCandidatesMatter++;
Expand Down Expand Up @@ -332,7 +340,7 @@ struct CoalescenceTreeProducer {
continue;

// Apply momentum-space selection
const bool passSkim = passThreeBodySkim(proton, neutron, lambda);
const bool passSkim = passThreeBodySkim(proton, neutron, lambda, massHypertriton);
if (!passSkim)
continue;

Expand Down
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