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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/UnstableParticles.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
RIVET_DEFAULT_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(UnstableParticles(), "UFS");
// Book histograms
book(_histXeKStar892 , 1, 1, 1);
book(_histMeanKStar892 , 2, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const FinalState& fs = apply<FinalState>(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 beams and average beam momentum
const ParticlePair& beams = apply<Beam>(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 UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
for (const Particle& p : ufs.particles(Cuts::abspid==323)) {
double xp = p.p3().mod()/meanBeamMom;
_histXeKStar892->fill(xp);
_histMeanKStar892->fill(_histMeanKStar892->bin(0).xMid());
}
}
/// 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
RIVET_DECLARE_PLUGIN(OPAL_1993_I342766);
}
|