Rivet analyses

title: TASSO_1980_I153511

Event shapes at 12 and 30 GeV

Experiment: TASSO (Petra)

Inspire ID: 153511

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B94 (1980) 437-443, 1980

Beams: e- e+

Beam energies: (6.0, 6.0); (15.0, 15.0)GeV

Run details: - $e^+e^-\to$ hadrons.

Sphericity, Aplanarity and scaled momentum distribution at 12 and 30 GeV.

Source code:TASSO_1980_I153511.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/Sphericity.hh"

namespace Rivet {

/// @brief Add a short analysis description here class TASSO_1980_I153511 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1980_I153511);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(Beam(), "Beams");

  const ChargedFinalState cfs;
  declare(cfs, "CFS");

  // Thrust and sphericity
  declare(Sphericity(cfs), "Sphericity");

  // Book histograms
  size_t ih = 1;
  for (double eVal : allowedEnergies()) {
    const string en = toString(round(eVal));
    if (isCompatibleWithSqrtS(eVal)) _sqs = en;
    book(_h[en + "S"], ih, 1, 1);
    book(_h[en + "A"], 2 + ih, 1, 1);
    book(_h[en + "x"], 4 + ih, 1, 1);
    ++ih;
  }
  raiseBeamErrorIf(_sqs.empty());
}


/// 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 = 0.5 * (beams.first.p3().mod() + beams.second.p3().mod());
  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
  _h[_sqs + "S"]->fill(sphericity.sphericity());
  _h[_sqs + "A"]->fill(sphericity.aplanarity());
  for (const Particle& p : cfs.particles()) {
    const Vector3 mom3 = p.p3();
    const double mom = mom3.mod();
    const double xp = mom / meanBeamMom;
    _h[_sqs + "x"]->fill(xp);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h);
}

/// @}


/// @name Histograms
/// @{
map<string, Histo1DPtr> _h;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(TASSO_1980_I153511); } ```