// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief Xi_c0 -> Xi0 K+K-
class BELLE_2021_I1835729 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2021_I1835729);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==4132);
declare(ufs, "UFS");
DecayedParticles XIC0(ufs);
XIC0.addStable(PID::PI0);
XIC0.addStable(PID::K0S);
XIC0.addStable(PID::ETA);
XIC0.addStable(PID::ETAPRIME);
XIC0.addStable(PID::XI0);
declare(XIC0, "XIC0");
// histograms
for(unsigned int ix=0;ix<3;++ix)
book(_h[ix],1,1,1+ix);
book(_dalitz, "dalitz",50,0.9,1.4,50,3.2,4.);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { {-321,1},{ 321,1}, { PID::XI0,1}};
static const map<PdgId,unsigned int> & modeCC = { { 321,1},{-321,1}, {-PID::XI0,1}};
DecayedParticles XIC0 = apply<DecayedParticles>(event, "XIC0");
// loop over particles
for(unsigned int ix=0;ix<XIC0.decaying().size();++ix) {
int sign = 1;
if (XIC0.decaying()[ix].pid()>0 && XIC0.modeMatches(ix,3,mode)) {
sign=1;
}
else if (XIC0.decaying()[ix].pid()<0 && XIC0.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particles & xi0 = XIC0.decayProducts()[ix].at( sign*PID::XI0);
const Particles & Kp = XIC0.decayProducts()[ix].at( sign*PID::KPLUS);
const Particles & Km = XIC0.decayProducts()[ix].at( sign*PID::KMINUS);
double mXiKp = (xi0[0].momentum()+Kp[0].momentum()).mass2();
double mXiKm = (xi0[0].momentum()+Km[0].momentum()).mass2();
double mKK = (Kp [0].momentum()+Km[0].momentum()).mass2();
_dalitz ->fill(mKK,mXiKm);
_h[0]->fill(sqrt(mKK ));
_h[1]->fill(sqrt(mXiKm));
_h[2]->fill(sqrt(mXiKp));
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix)
normalize(_h[ix]);
normalize(_dalitz );
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[3];
Histo2DPtr _dalitz;
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2021_I1835729);
}