// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief
class LHCB_2018_I1704426 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2018_I1704426);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
declare(ufs, "UFS");
DecayedParticles D0(ufs);
D0.addStable(PID::PI0);
D0.addStable(PID::K0S);
D0.addStable(PID::ETA);
D0.addStable(PID::ETAPRIME);
declare(D0, "D0");
// histograms
for(unsigned int ix=0;ix<2;++ix)
book(_h[ix ],1,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// define the decay mode
static const map<PdgId,unsigned int> & mode = { { 321,1}, { -321,1}, { 211,1}, { -211,1}};
DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
// loop over particles
for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
int sign = D0.decaying()[ix].pid()/421;
if ( D0.modeMatches(ix,4,mode)) {
const Particles & Kp = D0.decayProducts()[ix].at( sign*321);
const Particles & Km = D0.decayProducts()[ix].at(-sign*321);
const Particles & pip= D0.decayProducts()[ix].at( sign*211);
const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
double mpipi = (pip[0].momentum()+pim[0].momentum()).mass();
if(mpipi>0.4802 && mpipi<0.5072) continue;
_h[0]->fill((Kp [0].momentum()+Km [0].momentum()).mass()/MeV);
_h[1]->fill(mpipi/MeV);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<2;++ix)
normalize(_h[ix],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[2];
/// @}
};
RIVET_DECLARE_PLUGIN(LHCB_2018_I1704426);
}