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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief tau -> (5pi)-pi0
class CLEOII_1994_I373188 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1994_I373188);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
declare(UnstableParticles(), "UFS");
book(_hist, 1, 1, 1);
}
void findDecayProducts(const Particle & mother,
unsigned int & nstable,
Particles& pim, Particles& pi0) {
for(const Particle & p : mother.children()) {
long id = p.abspid();
if (id == PID::PI0 ) {
pi0.push_back(p);
++nstable;
}
else if (abs(id) == PID::PIPLUS) {
pim.push_back(p);
++nstable;
}
else if ( !p.children().empty() ) {
findDecayProducts(p, nstable, pim,pi0);
}
else
++nstable;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
for (const Particle& p : ufs.particles(Cuts::abspid==PID::TAU)) {
Particles pi0,pim;
unsigned int nstable = 0;
// find the decay products we want
findDecayProducts(p, nstable, pim, pi0);
if (nstable != 7) continue;
// K eta
if (pim.size() == 5 && pi0.size() == 1) {
FourMomentum phad=pi0[0].momentum();
for(const Particle & p2: pim)
phad += p2.momentum();
_hist->fill(phad.mass());
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_hist);
}
///@}
/// @name Histograms
///@{
Histo1DPtr _hist;
///@}
};
RIVET_DECLARE_PLUGIN(CLEOII_1994_I373188);
}
|