Rivet analyses

title: PLUTO_1980_I154270

Hadronic charged multiplicity measurement between 12 and 31.3 GeV

Experiment: PLUTO (PETRA)

Inspire ID: 154270

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. 95B (1980) 313-317

Beams: e+ e-

Beam energies: (4.7, 4.7); (6.0, 6.0); (6.5, 6.5); (8.5, 8.5); (11.0, 11.0); (13.8, 13.8); (15.1, 15.1); (15.3, 15.3); (15.7, 15.7)GeV

Run details: - Hadronic e+ e- events generated below the Z pole.

The charged particle multiplicity distribution of hadronic $e^+e^-$ events as measured between 12 and 31.3 GeV using the PLUTO detector at PETRA. The decay products of weakly decaying strange hadrons, e.g. $K^0_s$ and $\Lambda^0$, are not included in the measurement.

Source code:PLUTO_1980_I154270.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief Hadronic charged multiplicity measurement between 12 and 31.3 GeV class PLUTO_1980_I154270 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1980_I154270);


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

/// Book histograms and initialise projections before the run
void init() {
  const ChargedFinalState cfs;
  declare(cfs, "CFS");
  book(_mult, 1, 1, 1);
  for (const string& en : _mult.binning().edges<0>()) {
    const size_t idx = en.find("-");
    if (idx != string::npos) {
      const double emin = stod(en.substr(0, idx));
      const double emax = stod(en.substr(idx + 1, string::npos));
      if (inRange(sqrtS() / GeV, emin, emax)) {
        _sqs = en;
        break;
      }
    }
    else {
      const double eval = stod(en) * GeV;
      if (isCompatibleWithSqrtS(eval)) {
        _sqs = en;
        break;
      }
    }
  }
  raiseBeamErrorIf(_sqs.empty());
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& cfs = apply<FinalState>(event, "CFS");
  MSG_DEBUG("Total charged multiplicity = " << cfs.size());
  unsigned int nPart(0);
  for (const Particle& p : cfs.particles()) {
    // check if prompt or not
    ConstGenParticlePtr pmother = p.genParticle();
    ConstGenVertexPtr ivertex = pmother->production_vertex();
    bool prompt = true;
    while (ivertex) {
      vector<ConstGenParticlePtr> inparts = HepMCUtils::particles(ivertex, Relatives::PARENTS);
      int n_inparts = inparts.size();
      if (n_inparts < 1) break;
      pmother = inparts[0]; // first mother particle
      int mother_pid = abs(pmother->pdg_id());
      if (mother_pid == PID::K0S || mother_pid == PID::LAMBDA) {
        prompt = false;
        break;
      }
      else if (mother_pid < 6)
        break;
      ivertex = pmother->production_vertex();
    }
    if (prompt) ++nPart;
  }
  _mult->fill(_sqs, nPart);
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_mult, 1. / sumOfWeights());
}

/// @}

private:

BinnedProfilePtr<string> _mult;
string _sqs = "";

};

RIVET_DECLARE_PLUGIN(PLUTO_1980_I154270);

} ```