// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D0 -> 2pi+2pi-
class FOCUS_2007_I741543 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(FOCUS_2007_I741543);
/// @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<4;++ix)
book(_h[ix ],1,1,1+ix);
book(_h[4],2,1,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// define the decay mode
static const map<PdgId,unsigned int> & mode1 = { { 211,2}, { -211,2}};
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,mode1)) {
const Particles & pip= D0.decayProducts()[ix].at( sign*211);
const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
set<double> mpm;
for(unsigned int ix=0;ix<2;++ix) {
for(unsigned int iy=0;iy<2;++iy) {
double m = (pip[ix].momentum()+pim[iy].momentum()).mass();
_h[0]->fill(m);
mpm.insert(m);
}
}
_h[1]->fill(*mpm.rbegin());
_h[2]->fill(*mpm.begin());
FourMomentum ppp = pip[0].momentum()+pip[1].momentum();
_h[3]->fill(ppp.mass());
FourMomentum pmm = pim[0].momentum()+pim[1].momentum();
_h[3]->fill(pmm.mass());
for(unsigned int ix=0;ix<2;++ix) {
_h[4]->fill((ppp+pim[ix].momentum()).mass());
_h[4]->fill((pmm+pip[ix].momentum()).mass());
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<5;++ix)
normalize(_h[ix],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[5];
/// @}
};
RIVET_DECLARE_PLUGIN(FOCUS_2007_I741543);
}