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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief Add a short analysis description here
class MC_Eta_Decay : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MC_Eta_Decay);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
// Book histograms
double meta[2]={547.45, 957.78};
for(unsigned int ix=0;ix<2;++ix) {
std::ostringstream title; title << "_" << ix;
_mgammagamma.push_back(Histo1DPtr());
book(_mgammagamma.back(), "mgammagamma" +title.str(),200,0.,meta[ix]);
_mpi0gamma.push_back(Histo1DPtr());
book(_mpi0gamma.back(), "mpi0gamma" +title.str(),200,0.,meta[ix]);
_mpipgamma.push_back(Histo1DPtr());
book(_mpipgamma.back(), "mpipgamma" +title.str(),200,0.,meta[ix]);
_mpimgamma.push_back(Histo1DPtr());
book(_mpimgamma.back(), "mpimgamma" +title.str(),200,0.,meta[ix]);
_photonenergy.push_back(Histo1DPtr());
book(_photonenergy.back(), "photonenergy"+title.str(),200,0.,meta[ix]);
_mpippim.push_back(Histo1DPtr());
book(_mpippim.back(), "mpippim" +title.str(),200,0.,meta[ix]);
_dpippim.push_back(Histo1DPtr());
book(_dpippim.back(), "dpippim" +title.str(),200,200.,meta[ix]);
_dpi0pi0.push_back(Histo1DPtr());
book(_dpi0pi0.back(), "dpi0pi0" +title.str(),200,200.,meta[ix]);
_dpi0pip.push_back(Histo1DPtr());
book(_dpi0pip.back(), "dpi0pip" +title.str(),200,200.,meta[ix]);
_dpi0pim.push_back(Histo1DPtr());
book(_dpi0pim.back(), "dpi0pim" +title.str(),200,200.,meta[ix]);
}
_dpi0pi0.push_back(Histo1DPtr());
book(_dpi0pi0.back(), "dpi0pi0_2",200,200.,500. );
_dpippim.push_back(Histo1DPtr());
book(_dpippim.back(), "dpippim_2",200,200.,500. );
book(_dpipeta, "dpipeta",200,500.,meta[1]) ;
book(_dpimeta, "dpimeta",200,500.,meta[1]) ;
book(_dpi0eta, "dpi0eta",200,500.,meta[1]) ;
}
void findDecayProducts(const Particle & mother,
unsigned int & nstable,
Particles& pip, Particles& pim,
Particles& pi0, Particles& eta,
Particles& gamma) {
for(const Particle & p : mother.children()) {
int id = p.pid();
if ( id == PID::ETA ) {
eta.push_back(p);
++nstable;
}
else if ( id == PID::PHOTON ) {
gamma.push_back(p);
++nstable;
}
else if (id == PID::PIPLUS) {
pip.push_back(p);
++nstable;
}
else if (id == PID::PIMINUS) {
pim.push_back(p);
++nstable;
}
else if (id == PID::PI0 ) {
pi0.push_back(p);
++nstable;
}
else if (id == PID::K0S || id == PID::K0L ||
id == PID::KPLUS || id == PID::KMINUS)
++nstable;
else if ( !p.children().empty() ) {
findDecayProducts(p,nstable,pip,pim,pi0,eta,gamma);
}
else
++nstable;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Loop over f_1 mesons
for(const Particle& meson : apply<UnstableParticles>(event, "UFS").
particles(Cuts::pid==221||Cuts::pid==331)) {
unsigned int nstable(0);
Particles pip, pim, pi0, eta, gamma;
findDecayProducts(meson,nstable,pip, pim, pi0, eta, gamma);
unsigned int imeson = meson.pid()==221 ? 0 : 1;
// pi0 gamma gamma
if(nstable==3 && pi0.size()==1 && gamma.size()==2) {
_mgammagamma[imeson]->fill((gamma[0].momentum()+gamma[1].momentum()).mass()/MeV);
_mpi0gamma [imeson]->fill(( pi0[0].momentum()+gamma[0].momentum()).mass()/MeV);
_mpi0gamma [imeson]->fill(( pi0[0].momentum()+gamma[1].momentum()).mass()/MeV);
} // pi+pi-gamma analysis
else if(nstable==3 && pip.size()==1 && pim.size()==1 && gamma.size()==1) {
FourMomentum ptemp = pip[0].momentum()+pim[0].momentum();
double mpipi = ptemp.mass();
_mpippim[imeson]->fill(mpipi/MeV);
double egamma = 0.5*(meson.mass()*meson.mass()-mpipi*mpipi)/meson.mass();
_photonenergy[imeson]->fill(egamma/MeV);
_mpipgamma[imeson]->fill((pip[0].momentum()+gamma[0].momentum()).mass()/MeV);
_mpimgamma[imeson]->fill((pim[0].momentum()+gamma[0].momentum()).mass()/MeV);
}
else if(nstable==3&& pi0.size()==3) {
_dpi0pi0[imeson]->fill((pi0[0].momentum()+pi0[1].momentum()).mass()/MeV);
_dpi0pi0[imeson]->fill((pi0[0].momentum()+pi0[2].momentum()).mass()/MeV);
_dpi0pi0[imeson]->fill((pi0[1].momentum()+pi0[2].momentum()).mass()/MeV);
}
else if(nstable==3&& pip.size()==1&&pim.size()==1&&pi0.size()==1) {
_dpi0pip[imeson]->fill((pi0[0].momentum()+pip[0].momentum()).mass()/MeV);
_dpi0pim[imeson]->fill((pi0[0].momentum()+pim[0].momentum()).mass()/MeV);
_dpippim[imeson]->fill((pip[0].momentum()+pim[0].momentum()).mass()/MeV);
}
else if(nstable==3&& pi0.size()==2&&eta.size()==1) {
_dpi0pi0[2]->fill((pi0[0].momentum()+pi0[1].momentum()).mass()/MeV);
_dpi0eta ->fill((pi0[0].momentum()+eta[0].momentum()).mass()/MeV);
_dpi0eta ->fill((pi0[1].momentum()+eta[0].momentum()).mass()/MeV);
}
else if(nstable==3&& pip.size()==1&&pim.size()==1&&eta.size()==1) {
_dpippim[2]->fill((pip[0].momentum()+pim[0].momentum()).mass()/MeV);
_dpipeta ->fill((pip[0].momentum()+eta[0].momentum()).mass()/MeV);
_dpimeta ->fill((pim[0].momentum()+eta[0].momentum()).mass()/MeV);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
// normalize to unity
for(unsigned int ix=0;ix<2;++ix) {
normalize(_mgammagamma[ix]);
normalize(_mpi0gamma[ix]);
normalize(_mpipgamma[ix]);
normalize(_mpimgamma[ix]);
normalize(_mpippim[ix]);
normalize(_photonenergy[ix]);
normalize(_dpippim[ix]);
normalize(_dpi0pi0[ix]);
normalize(_dpi0pip[ix]);
normalize(_dpi0pim[ix]);
}
normalize(_dpi0pi0[2]);
normalize(_dpippim[2]);
normalize(_dpipeta);
normalize(_dpimeta);
normalize(_dpi0eta);
}
//@}
/**
* Histograms for the decay \f$\eta\to\pi^0\gamma\gamma\f$
*/
//@{
/**
* Histogram for the mass of \f$\gamma\gamma\f$
*/
vector<Histo1DPtr> _mgammagamma;
/**
* Histogrma for the mass of \f$\pi^0\gamma\f$
*/
vector<Histo1DPtr> _mpi0gamma;
//@}
/**
* Histograms for the decay \f$\eta\to\pi^+\pi^-\gamma\f$
*/
//@{
/**
* Histogram for the mass of \f$\pi^+\gamma\f$
*/
vector<Histo1DPtr> _mpipgamma;
/**
* Histogram for the mass of \f$\pi^-\gamma\f$
*/
vector<Histo1DPtr> _mpimgamma;
/**
* Histogram for the mass of \f$\pi^+\pi^-\f$
*/
vector<Histo1DPtr> _mpippim;
/**
* Histogram for the photon energy
*/
vector<Histo1DPtr> _photonenergy;
//@}
/**
* Histograms for the decay \f$\eta\pi\pi\pi\f$ and \f$\eta'\to\eta\pi\pi\f$.
*/
//@{
/**
* Histogram for the mass of \f$\pi^+\pi^-\f$
*/
vector<Histo1DPtr> _dpippim;
/**
* Histogram for the mass of \f$\pi^0\pi^0\f$
*/
vector<Histo1DPtr> _dpi0pi0;
/**
* Histogram for the mass of \f$\pi^0\pi^+\f$
*/
vector<Histo1DPtr> _dpi0pip;
/**
* Histogram for the mass of \f$\pi^0\pi^-\f$
*/
vector<Histo1DPtr> _dpi0pim;
/**
* Histogram for the mass of \f$\pi^+\eta\f$
*/
Histo1DPtr _dpipeta;
/**
* Histogram for the mass of \f$\pi^-\eta\f$
*/
Histo1DPtr _dpimeta;
/**
* Histogram for the mass of \f$\pi^0\eta\f$
*/
Histo1DPtr _dpi0eta;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(MC_Eta_Decay);
}
|