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## Rivet analyses reference

### DELPHI_1995_S3137023

Strange baryon production in $Z$ hadronic decays at Delphi
Experiment: DELPHI (LEP 1)
Inspire ID: 394716
Status: VALIDATED
Authors:
• Hendrik Hoeth
References:
• Z. Phys. C, 67, 543--554 (1995)
Beams: e+ e-
Beam energies: (45.6, 45.6) GeV
Run details:
• Hadronic Z decay events generated on the Z pole ($\sqrt{s} = 91.2$ GeV)

Measurement of the $\Xi^-$ and $\Sigma^+(1385)/\Sigma^-(1385)$ scaled momentum distributions by DELPHI at LEP 1. The paper also has the production cross-sections of these particles, but that's not implemented in Rivet.

Source code: DELPHI_1995_S3137023.cc
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/Beam.hh" #include "Rivet/Projections/FinalState.hh" #include "Rivet/Projections/ChargedFinalState.hh" #include "Rivet/Projections/UnstableParticles.hh" namespace Rivet { /// @brief DELPHI strange baryon paper /// @author Hendrik Hoeth class DELPHI_1995_S3137023 : public Analysis { public: /// Constructor DELPHI_1995_S3137023() : Analysis("DELPHI_1995_S3137023") {} /// @name Analysis methods //@{ void init() { declare(Beam(), "Beams"); declare(ChargedFinalState(), "FS"); declare(UnstableParticles(), "UFS"); book(_histXpXiMinus ,2, 1, 1); book(_histXpSigma1385Plus ,3, 1, 1); book(_weightedTotalNumXiMinus, "_weightedTotalNumXiMinus"); book(_weightedTotalNumSigma1385Plus, "_weightedTotalNumSigma1385Plus"); } void analyze(const Event& e) { // First, veto on leptonic events by requiring at least 4 charged FS particles const FinalState& fs = apply(e, "FS"); const size_t numParticles = fs.particles().size(); // Even if we only generate hadronic events, we still need a cut on numCharged >= 2. if (numParticles < 2) { MSG_DEBUG("Failed leptonic event cut"); vetoEvent; } MSG_DEBUG("Passed leptonic event cut"); // Get beams and average beam momentum const ParticlePair& beams = apply(e, "Beams").beams(); const double meanBeamMom = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0; MSG_DEBUG("Avg beam momentum = " << meanBeamMom); // Final state of unstable particles to get particle spectra const UnstableParticles& ufs = apply(e, "UFS"); for (const Particle& p : ufs.particles()) { const int id = p.abspid(); switch (id) { case 3312: _histXpXiMinus->fill(p.p3().mod()/meanBeamMom); _weightedTotalNumXiMinus->fill(); break; case 3114: case 3224: _histXpSigma1385Plus->fill(p.p3().mod()/meanBeamMom); _weightedTotalNumSigma1385Plus->fill(); break; } } } /// Finalize void finalize() { normalize(_histXpXiMinus , dbl(*_weightedTotalNumXiMinus)/sumOfWeights()); normalize(_histXpSigma1385Plus , dbl(*_weightedTotalNumSigma1385Plus)/sumOfWeights()); } //@} private: /// Store the weighted sums of numbers of charged / charged+neutral /// particles - used to calculate average number of particles for the /// inclusive single particle distributions' normalisations. CounterPtr _weightedTotalNumXiMinus; CounterPtr _weightedTotalNumSigma1385Plus; Histo1DPtr _histXpXiMinus; Histo1DPtr _histXpSigma1385Plus; //@} }; // The hook for the plugin system DECLARE_RIVET_PLUGIN(DELPHI_1995_S3137023); }