// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief chi_cJ -> 4 pi0
class BESIII_2010_I878544 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2010_I878544);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// projections
UnstableParticles ufs = UnstableParticles(Cuts::pid==10441 ||
Cuts::pid==445 ||
Cuts::pid==20443);
declare(ufs, "UFS");
DecayedParticles chi(ufs);
chi.addStable( PID::PI0);
declare(chi, "chi");
// histograms
for(unsigned int ix=0;ix<3;++ix)
book(_h[ix],1,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 111,4} };
DecayedParticles chi = apply<DecayedParticles>(event, "chi");
// loop over particles
for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
if(!chi.modeMatches(ix,4,mode)) continue;
const Particles & pi0 = chi.decayProducts()[ix].at(111);
unsigned int imode = 0;
if(chi.decaying()[ix].pid()==20443) imode=1;
else if(chi.decaying()[ix].pid()==445) imode=2;
for(unsigned int ix=0;ix<pi0.size();++ix) {
for(unsigned int iy=ix+1;iy<pi0.size();++iy) {
_h[imode]->fill((pi0[ix].momentum()+pi0[iy].momentum()).mass());
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix)
normalize(_h[ix]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[3];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2010_I878544);
}