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Rivet analyses reference
JADE_1990_I282847
Photon, $\pi^0$ and $\eta$ spectra in $e^+e^-$ collisions at 35 and 44 GeV
Experiment: JADE (Petra)
Inspire ID: 282847
Status: VALIDATED
Authors:
References:
- Z.Phys. C46 (1990) 1-7, 1990
Beams: e+ e-
Beam energies: (17.5, 17.5); (22.0, 22.0) GeV
Run details:
- e+ e- to hadrons. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.
Measurement of the Photon, $\pi^0$ and $\eta$ spectra in $e^+e^-$ collisions at 35 and 44 GeV by the JADE experiment at Petra. The isolated photon spectrum which tests ISR and FST QED radiation is not implemented. The multiplicities are not implemented as they are in the PDG averages. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.
Source code:
JADE_1990_I282847.cc
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90 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/Beam.hh"
namespace Rivet {
/// @brief gamma, pi0 and eta spectra at 35 and 44 GeV
class JADE_1990_I282847 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(JADE_1990_I282847);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
declare(Beam(), "Beams");
declare(FinalState(), "FS");
declare(UnstableParticles(), "UFS");
int ioff=-1;
if(isCompatibleWithSqrtS(35)) {
ioff=0;
}
else if(isCompatibleWithSqrtS(44.)) {
ioff=1;
}
else
MSG_ERROR("Beam energy " << sqrtS() << " not supported!");
// Book histograms
book(_h_gamma, 1+ioff, 1, 1);
book(_h_pi0 , 3+ioff, 1, 1);
if(ioff==0) book(_h_eta, 5+ioff, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Get beams and average beam momentum
const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
const double meanBeamMom = ( beams.first.p3().mod() +
beams.second.p3().mod() ) / 2.0;
// gamma
const FinalState& fs = apply<FinalState>(event, "FS");
for (const Particle& p : fs.particles(Cuts::pid==22)) {
double xE = p.E()/meanBeamMom;
_h_gamma->fill(xE);
}
// pi0, eta
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
for (const Particle& p : ufs.particles(Cuts::pid==111 or Cuts::pid==221)) {
double modp = p.p3().mod();
double xE = p.E()/meanBeamMom;
double beta = modp/p.E();
if(p.pid()==111)
_h_pi0->fill(xE,1./beta);
else if(_h_eta)
_h_eta->fill(xE,1./beta);
}
}
/// Normalise histograms etc., after the run
void finalize() {
scale(_h_gamma, crossSection()*sqr(sqrtS())/microbarn/sumOfWeights());
scale(_h_pi0 , crossSection()*sqr(sqrtS())/microbarn/sumOfWeights());
if(_h_eta) scale(_h_eta , crossSection()*sqr(sqrtS())/microbarn/sumOfWeights());
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_gamma, _h_pi0, _h_eta;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(JADE_1990_I282847);
}
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