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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief phi -> 3 pion decay
class SND_2001_I558279 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(SND_2001_I558279);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
// Book histograms
book(_h_pm, 1, 1, 1);
book(_h_p0, 2, 1, 1);
}
void findDecayProducts(const Particle & mother, unsigned int & nstable, Particles &pip,
Particles &pim, Particles &pi0) {
for(const Particle & p : mother.children()) {
int id = p.pid();
if (id == PID::PIMINUS ) {
pim.push_back(p);
++nstable;
}
else if (id == PID::PIPLUS) {
pip.push_back(p);
++nstable;
}
else if (id == PID::PI0) {
pi0.push_back(p);
++nstable;
}
else if ( !p.children().empty() ) {
findDecayProducts(p, nstable, pip,pim,pi0);
}
else
++nstable;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==333)) {
Particles pip,pim,pi0;
unsigned int nstable(0);
findDecayProducts(p, nstable, pip,pim,pi0);
if(nstable==3 && pip.size()==1 && pim.size()==1&&pi0.size()==1) {
_h_pm->fill((pip[0].momentum()+pim[0].momentum()).mass()/MeV);
_h_p0->fill((pip[0].momentum()+pi0[0].momentum()).mass()/MeV);
_h_p0->fill((pim[0].momentum()+pi0[0].momentum()).mass()/MeV);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_pm);
normalize(_h_p0);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_pm,_h_p0;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(SND_2001_I558279);
}
|