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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/Beam.hh"
namespace Rivet {
/// @brief OPAL b-fragmentation measurement for weak B-hadron decays
/// @author Simone Amoroso
class OPAL_2003_I599181 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_2003_I599181);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(Beam(), "Beams");
declare(UnstableParticles(), "UFS");
// Book histograms
book(_histXbweak ,1, 1, 1);
book(_histMeanXbweak ,2, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// 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);
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
// Get Bottom hadrons
const Particles bhads = filter_select(ufs.particles(), isBottomHadron);
for (const Particle& bhad : bhads) {
// Check for weak decay, i.e. no more bottom present in children
if (bhad.children(lastParticleWith(hasBottom)).empty()) {
const double xp = bhad.E()/meanBeamMom;
_histXbweak->fill(xp);
_histMeanXbweak->fill(_histMeanXbweak->bin(0).xMid(), xp);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_histXbweak);
}
//@}
private:
Histo1DPtr _histXbweak;
Profile1DPtr _histMeanXbweak;
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(OPAL_2003_I599181);
}
|