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105 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief chi_c -> p nbar pi- p nbar pi- pi0
class BESIII_2012_I1128258 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2012_I1128258);
/// @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==20444);
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);
book(_h[3],2,1,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { { 2212,1}, {-2112,1}, {-211,1}};
static const map<PdgId,unsigned int> & mode1CC = { {-2212,1}, { 2112,1}, { 211,1}};
static const map<PdgId,unsigned int> & mode2 = { { 2212,1}, {-2112,1}, {-211,1}, {111,1}};
static const map<PdgId,unsigned int> & mode2CC = { {-2212,1}, { 2112,1}, { 211,1}, {111,1}};
DecayedParticles chi = apply<DecayedParticles>(event, "chi");
// loop over particles
for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
int mode=-1,sign=0;
if (chi.decaying()[ix].pid()==10441) {
if(chi.modeMatches(ix,3,mode1)) {
mode=0;
sign=1;
}
else if(chi.modeMatches(ix,3,mode1CC)) {
mode= 0;
sign=-1;
}
}
if(mode==0) {
const Particle & pim = chi.decayProducts()[ix].at( -211*sign)[0];
const Particle & pp = chi.decayProducts()[ix].at( 2212*sign)[0];
const Particle & nbar = chi.decayProducts()[ix].at(-2112*sign)[0];
_h[0]->fill((pp .momentum()+pim .momentum()).mass());
_h[1]->fill((nbar.momentum()+pim .momentum()).mass());
_h[2]->fill((pp .momentum()+nbar.momentum()).mass());
continue;
}
else if(chi.modeMatches(ix,4,mode2)) {
mode=1;
sign=1;
}
else if(chi.modeMatches(ix,4,mode2CC)) {
mode= 1;
sign=-1;
}
else
continue;
const Particle & pim = chi.decayProducts()[ix].at( -211*sign)[0];
const Particle & pi0 = chi.decayProducts()[ix].at( 111 )[0];
_h[3]->fill((pim.momentum()+pi0.momentum()).mass());
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<4;++ix)
normalize(_h[ix]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[4];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2012_I1128258);
}
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