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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief D0 -> eta pi+pi- decays
class CLEOC_2008_I779705 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEOC_2008_I779705);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// projections
declare(UnstableParticles(),"UFS");
// histograms
book(_h_eta_pi,1,1,1);
book(_h_pi_pi ,1,1,2);
}
void findDecay(const Particle & parent, unsigned int & nstable,
Particles & pip, Particles & pim, Particles & eta) {
for(const Particle & p : parent.children()) {
if(p.pid()==PID::PIPLUS) {
++nstable;
pip.push_back(p);
}
else if(p.pid()==PID::PIMINUS) {
++nstable;
pim.push_back(p);
}
else if(p.pid()==PID::ETA) {
++nstable;
eta.push_back(p);
}
else if(p.children().empty() || p.pid()==PID::K0S) {
++nstable;
}
else {
findDecay(p,nstable,pip,pim,eta);
}
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle & D0 : apply<UnstableParticles>(event,"UFS").particles(Cuts::abspid==421)) {
unsigned int nstable(0);
Particles pip, pim, eta;
findDecay(D0,nstable,pip,pim,eta);
if(nstable==3 && pip.size()==1 && pim.size()==1 && eta.size()==1) {
if(D0.pid()<0) swap (pip,pim);
_h_eta_pi->fill((pip[0].momentum()+eta[0].momentum()).mass());
_h_pi_pi ->fill((pip[0].momentum()+pim[0].momentum()).mass());
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_eta_pi);
normalize(_h_pi_pi );
}
///@}
/// @name Histograms
///@{
Histo1DPtr _h_eta_pi,_h_pi_pi;
///@}
};
RIVET_DECLARE_PLUGIN(CLEOC_2008_I779705);
}
|