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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief D* production
class OPAL_1995_I382219 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_1995_I382219);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
declare(Beam(), "Beams");
declare(UnstableParticles(), "UFS");
book(_h_Xe_Ds , 3, 1, 1);
book(_h_Xe_Ds_b, 4, 1, 1);
book(_h_Xe_Ds_c, 5, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
// 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/GeV;
// check if b hadrons or not
unsigned int nB= (filter_select(ufs.particles(), isBottomHadron)).size();
// Accept all D*+- decays.
for (const Particle& p : filter_select(ufs.particles(), Cuts::abspid==PID::DSTARPLUS)) {
// Scaled energy.
const double energy = p.E()/GeV;
const double scaledEnergy = energy/meanBeamMom;
_h_Xe_Ds->fill(scaledEnergy);
if(nB==0)
_h_Xe_Ds_c->fill(scaledEnergy);
else
_h_Xe_Ds_b->fill(scaledEnergy);
}
}
/// Normalise histograms etc., after the run
void finalize() {
// brs for D*+/- -> D0 pi+/- and D0->K+pi-
double br = 0.677*0.03950;
scale(_h_Xe_Ds , 1./sumOfWeights()*br);
scale(_h_Xe_Ds_b, 1./sumOfWeights()*br);
scale(_h_Xe_Ds_c, 1./sumOfWeights()*br);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_Xe_Ds,_h_Xe_Ds_b,_h_Xe_Ds_c;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(OPAL_1995_I382219);
}
|