// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief chi_cJ -> Lambda Lambdabar0 eta
class BESIII_2022_I2166668 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2166668);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
UnstableParticles ufs = UnstableParticles(Cuts::pid==10441 or
Cuts::pid==20443 or
Cuts::pid==445);
declare(ufs, "UFS");
DecayedParticles chi(ufs);
chi.addStable( PID::ETA);
chi.addStable( PID::LAMBDA);
chi.addStable(-PID::LAMBDA);
declare(chi, "chi");
// histos
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 = { { 3122,1}, {-3122,1}, { 221,1} };
DecayedParticles chi = apply<DecayedParticles>(event, "chi");
for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
if(!chi.modeMatches(ix,3,mode)) continue;
const Particle & lam = chi.decayProducts()[ix].at( 3122)[0];
const Particle & lamb = chi.decayProducts()[ix].at(-3122)[0];
const Particle & eta = chi.decayProducts()[ix].at( 221)[0];
_h[0]->fill((lam .momentum()+lamb.momentum()).mass());
_h[1]->fill((lam .momentum()+eta .momentum()).mass());
_h[2]->fill((lamb.momentum()+eta .momentum()).mass());
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix)
normalize(_h[ix],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[3];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2022_I2166668);
}