Rivet analyses

title: SLD_1995_I378545

Event Shapes at 91.2 GeV

Experiment: SLD (SLC)

Inspire ID: 378545

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 51 (1995) 962-984, 1995

Beams: e+ e-

Beam energies: (45.6, 45.6)GeV

Run details: - e+e- to hadrons

Measurement of event shapes by the SLD experiment. Jet rates not implemented.

Source code:SLD_1995_I378545.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/Hemispheres.hh"

include "Rivet/Projections/ParisiTensor.hh"

include "Rivet/Projections/Sphericity.hh"

include "Rivet/Projections/Thrust.hh"

//#include "Rivet/Projections/FastJets.hh"

namespace Rivet {

/// @brief Event shapes at MZ class SLD_1995_I378545 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(SLD_1995_I378545);


/// @name Analysis methods
///@{

/// Book histograms and initialise projections before the run
void init() {
  const FinalState fs;
  declare(fs, "FS");
  const ChargedFinalState cfs;
  declare(cfs, "CFS");
  Sphericity sphere(fs);
  declare(sphere, "Sphericity");
  declare(Thrust(fs), "Thrust");
  declare(Hemispheres(sphere), "Hemispheres");
  declare(ParisiTensor(fs), "Parisi");
  // declare(FastJets(fs, JetAlg::DURHAM, 0.7), "DurhamJets");
  // declare(FastJets(fs, JetAlg::JADE       ), "JadeJets"  );
  // histograms
  book(_histThrust, 2, 1, 1);
  book(_histMJetHigh, 3, 1, 1);
  book(_histBT, 4, 1, 1);
  book(_histBW, 5, 1, 1);
  book(_histOblateness, 6, 1, 1);
  book(_histC, 7, 1, 1);
  // book(_histy23JADE    , 8, 1, 1);
  // book(_histy23Durham  ,12, 1, 1);
  book(_histEEC, 14, 1, 1);
  book(_histAEEC, 15, 1, 1);
  book(_histJCEF, 16, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");
  if (fs.particles().size() < 2) vetoEvent;
  // thrust
  const Thrust& thrust = apply<Thrust>(event, "Thrust");
  _histThrust->fill(1. - thrust.thrust());
  _histOblateness->fill(thrust.oblateness());
  // visible energy
  double Evis = 0.0;
  for (const Particle& p : fs.particles()) {
    Evis += p.E();
  }
  double Evis2 = sqr(Evis);
  // (A)EEC
  // Need iterators since second loop starts at current outer loop iterator, i.e. no "foreach" here!
  for (Particles::const_iterator p_i = fs.particles().begin(); p_i != fs.particles().end(); ++p_i) {
    for (Particles::const_iterator p_j = p_i; p_j != fs.particles().end(); ++p_j) {
      const Vector3 mom3_i = p_i->momentum().p3();
      const Vector3 mom3_j = p_j->momentum().p3();
      const double energy_i = p_i->momentum().E();
      const double energy_j = p_j->momentum().E();
      const double thetaij = 180. * mom3_i.unit().angle(mom3_j.unit()) / M_PI;
      double eec = (energy_i * energy_j) / Evis2;
      if (p_i != p_j) eec *= 2.;
      _histEEC->fill(thetaij, eec);
      if (thetaij < 90.) {
        _histAEEC->fill(thetaij, -eec);
      }
      else {
        _histAEEC->fill(180. - thetaij, eec);
      }
    }
  }
  // hemisphere related
  const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");
  _histMJetHigh->fill(hemi.scaledM2high());
  _histBW->fill(hemi.Bmax());
  _histBT->fill(hemi.Bsum());
  // C-parameter
  const ParisiTensor& parisi = apply<ParisiTensor>(event, "Parisi");
  _histC->fill(parisi.C());
  // jets
  // const FastJets&  durjet = apply<FastJets>(event, "DurhamJets");
  // const FastJets& jadejet = apply<FastJets>(event, "JadeJets");
  // if (durjet .clusterSeq()) _histy23Durham->fill( durjet.clusterSeq()->exclusive_ymerge_max(2));
  // if (jadejet.clusterSeq()) _histy23JADE  ->fill(jadejet.clusterSeq()->exclusive_ymerge_max(2));
  // jet cone
  Vector3 jetAxis = thrust.thrustAxis();
  if (hemi.highMassDirection()) jetAxis *= -1.;
  for (const Particle& p : fs.particles()) {
    const double thetaij = 180. * jetAxis.angle(p.p3().unit()) / M_PI;
    double jcef = p.E() / Evis;
    _histJCEF->fill(thetaij, jcef);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_histThrust, 1. / sumOfWeights());
  scale(_histMJetHigh, 1. / sumOfWeights());
  scale(_histBT, 1. / sumOfWeights());
  scale(_histBW, 1. / sumOfWeights());
  scale(_histOblateness, 1. / sumOfWeights());
  scale(_histC, 1. / sumOfWeights());
  // scale(_histy23JADE    , 1./sumOfWeights());
  // scale(_histy23Durham  , 1./sumOfWeights());
  scale(_histEEC, 180. / M_PI / sumOfWeights());
  scale(_histAEEC, 180. / M_PI / sumOfWeights());
  scale(_histJCEF, 180. / M_PI / sumOfWeights());
}

///@}


/// @name Histograms
///@{
Histo1DPtr _histThrust, _histMJetHigh, _histBT, _histBW;
Histo1DPtr _histOblateness, _histC, _histy23JADE, _histy23Durham;
Histo1DPtr _histEEC, _histAEEC, _histJCEF;

///@}

};

RIVET_DECLARE_PLUGIN(SLD_1995_I378545);

} ```