// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief eta_c -> KS0 K+-pi-+
class BESIII_2012_I1187787 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2012_I1187787);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::pid==441);
declare(ufs, "UFS");
DecayedParticles etac(ufs);
etac.addStable(PID::PI0);
etac.addStable(PID::K0S);
etac.addStable(PID::ETA);
etac.addStable(PID::ETAPRIME);
declare(etac, "etac");
// histograms
book(_h_K0pip,1,1,1);
book(_h_K0Kp ,1,1,2);
book(_h_Kppip,1,1,3);
book(_dalitz, "dalitz",50,0.,8.,50,0.,8.);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 321,1}, {310,1}, {-211,1} };
static const map<PdgId,unsigned int> & modeCC = { {-321,1}, {310,1}, { 211,1} };
DecayedParticles etac = apply<DecayedParticles>(event, "etac");
// loop over particles
for(unsigned int ix=0;ix<etac.decaying().size();++ix) {
int sign=1;
if(etac.modeMatches(ix,3,mode)) {
sign=1;
}
else if(etac.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particle & KS0 = etac.decayProducts()[ix].at( 310)[0];
const Particle & pim = etac.decayProducts()[ix].at(-sign*211)[0];
const Particle & Kp = etac.decayProducts()[ix].at( sign*321)[0];
double mplus = (Kp .momentum() + pim.momentum()).mass2();
double mminus = (KS0.momentum() + pim.momentum()).mass2();
double mKK = (Kp .momentum() + KS0.momentum()).mass2();
_h_K0Kp ->fill(sqrt(mKK ));
_h_Kppip->fill(sqrt(mplus ));
_h_K0pip->fill(sqrt(mminus));
_dalitz->fill(mplus,mminus);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_Kppip);
normalize(_h_K0pip);
normalize(_h_K0Kp );
normalize(_dalitz );
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_Kppip,_h_K0pip,_h_K0Kp;
Histo2DPtr _dalitz;
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2012_I1187787);
}