Rivet analyses

title: TASSO_1980_I143691

Charged Particle distributions between 13 and 31.6 GeV

Experiment: TASSO (Petra)

Inspire ID: 143691

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. 89B (1980) 418-422

Beams: e- e+

Beam energies: (6.5, 6.5); (8.5, 8.5); (11.0, 11.0); (13.8, 13.8); (15.2, 15.2); (15.6, 15.6)GeV

Run details: - e+ e- to hadrons and e+ e- to mu+ mu- (for normalization).

Measurement of charged particle multiplicity, rapidity and scaled momentum distributions for a range of energies between 13 and 31.6 GeV.

Source code:TASSO_1980_I143691.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/Thrust.hh"

namespace Rivet {

/// @brief Charged particle multiplicities and distributions class TASSO_1980_I143691 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1980_I143691);


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

/// Book histograms and initialise projections before the run
void init() {

  // Initialise and register projections
  ChargedFinalState cfs;
  declare(cfs, "CFS");
  declare(Thrust(cfs), "Thrust");


  // Book histograms
  book(_p, 1, 1, 1);
  for (const string& en : _p.binning().edges<0>()) {
    if (isCompatibleWithSqrtS(stod(en) * GeV)) _sqs = en;
  }
  raiseBeamErrorIf(_sqs.empty());

  if (sqrtS() > 25 * GeV)
    _pre = "hi";
  else if (sqrtS() > 15 * GeV)
    _pre = "me";
  else
    _pre = "lo";
  book(_h["lorap"], 2, 1, 1);
  book(_h["lox"], 5, 1, 1);
  book(_h["merap"], 3, 1, 1);
  book(_h["mex"], 6, 1, 1);
  book(_h["hirap"], 4, 1, 1);
  book(_h["hix"], 7, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  // thrust
  const Thrust& thrust = apply<Thrust>(event, "Thrust");
  Vector3 axis = thrust.thrustAxis();
  _p->fill(_sqs, cfs.particles().size());
  for (const Particle& p : cfs.particles()) {
    const Vector3 mom3 = p.p3();
    double pp = mom3.mod();
    double xP = 2. * pp / sqrtS();
    _h[_pre + "x"]->fill(xP);
    const double mom = dot(axis, mom3);
    const double rap = 0.5 * log((p.E() + mom) / (p.E() - mom));
    _h[_pre + "rap"]->fill(fabs(rap));
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  for (auto& item : _h) {
    if (item.first.find("rap") != string::npos) {
      scale(item.second, 1.0 / sumOfWeights());
    }
    else {
      // These observables aren't well defined: the histograms are filled
      // for an energy range but the scaling requires a specific energy.
      scale(item.second, crossSection() * sqr(sqrtS()) / sumOfWeights() / microbarn);
    }
  }
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(TASSO_1980_I143691); } ```