// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief Add a short analysis description here
class BABAR_2018_I1679886 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2018_I1679886);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
declare(UnstableParticles(), "UFS");
book(_h_KK, 1, 1, 1);
}
void findDecayProducts(const Particle & mother, unsigned int & nstable,
unsigned int & nK0, unsigned int & nKp,
unsigned int & nKm, FourMomentum & ptot) {
for(const Particle & p : mother.children()) {
int id = p.pid();
if ( id == PID::KPLUS ) {
++nKp;
++nstable;
ptot += p.momentum();
}
else if (id == PID::KMINUS ) {
++nKm;
++nstable;
ptot += p.momentum();
}
else if (id == PID::K0S) {
++nK0;
++nstable;
ptot += p.momentum();
}
else if (id == PID::PI0 || id == PID::PIPLUS || id == PID::PIMINUS) {
++nstable;
}
else if ( !p.children().empty() ) {
findDecayProducts(p, nstable, nK0, nKp, nKm, ptot);
}
else
++nstable;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Loop over taus
for(const Particle& tau : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==PID::TAU)) {
unsigned int nstable(0),nK0(0),nKp(0),nKm(0);
FourMomentum p_tot(0,0,0,0);
findDecayProducts(tau, nstable, nK0, nKp, nKm, p_tot);
if (tau.pid() < 0) {
swap(nKp,nKm);
}
if(nstable!=3) continue;
if(nKm==1 && nK0==1 )
_h_KK->fill(p_tot.mass());
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_KK);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_KK;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(BABAR_2018_I1679886);
}