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## Rivet analyses reference

### OPAL_1993_I342766

A Measurement of $K^{*\pm}$ (892) production in hadronic Z0 decays
Experiment: OPAL (LEP)
Inspire ID: 342766
Status: VALIDATED
Authors:
• Simone Amoroso
References:
Beams: e+ e-
Beam energies: (45.6, 45.6) GeV
Run details:
• electron positron collisions at the Z0 resonance with hadronic decays

OPAL measurement of the inclusive cross section for K^{*\pm} (892) production in hadronic decays of the Z0

Source code: OPAL_1993_I342766.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 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/FinalState.hh" #include "Rivet/Projections/ChargedFinalState.hh" #include "Rivet/Projections/UnstableFinalState.hh" #include "Rivet/Projections/Beam.hh" namespace Rivet { /// @brief A Measurement of K*+- (892) production in hadronic Z0 decays /// @author Simone Amoroso class OPAL_1993_I342766 : public Analysis { public: /// Constructor DEFAULT_RIVET_ANALYSIS_CTOR(OPAL_1993_I342766); /// @name Analysis methods //@{ /// Book histograms and initialise projections before the run void init() { // Initialise and register projections declare(Beam(), "Beams"); declare(ChargedFinalState(), "FS"); declare(UnstableFinalState(), "UFS"); // Book histograms _histXeKStar892 = bookHisto1D( 1, 1, 1); _histMeanKStar892 = bookHisto1D( 2, 1, 1); } /// Perform the per-event analysis void analyze(const Event& event) { const FinalState& fs = apply(event, "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 event weight for histo filling const double weight = event.weight(); // Get beams and average beam momentum const ParticlePair& beams = apply(event, "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 UnstableFinalState& ufs = apply(event, "UFS"); foreach (const Particle& p, ufs.particles(Cuts::abspid==323)) { double xp = p.p3().mod()/meanBeamMom; _histXeKStar892->fill(xp, weight); _histMeanKStar892->fill(_histMeanKStar892->bin(0).xMid(), weight); } } /// Normalise histograms etc., after the run void finalize() { scale(_histXeKStar892, 1./sumOfWeights()); scale(_histMeanKStar892, 1./sumOfWeights()); } //@} private: /// @name Histograms Histo1DPtr _histXeKStar892; Histo1DPtr _histMeanKStar892; }; // The hook for the plugin system DECLARE_RIVET_PLUGIN(OPAL_1993_I342766); }