Rivet analyses

title: ARGUS_1992_I319102

Measurement of $R$ at 9.36 GeV and charged particle multiplicities in continuum and at the $\Upsilon(4S)$

Experiment: ARGUS (DORIS)

Inspire ID: 319102

Status: VALIDATED

Authors: - Peter Richardson

References: - Z.Phys. C54 (1992) 13-20, 1992

Beams: e- e+

Beam energies: (4.7, 4.7); (5.2, 5.2); (5.3, 5.3)GeV

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

Measurement of $R$ at 9.36 GeV and charged particle multiplicities in continuum and at the $\Upsilon(4S)$. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalculated if runs are combined.

Source code:ARGUS_1992_I319102.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief charged multiplicity at 4s and nearby continuum class ARGUS_1992_I319102 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1992_I319102);


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

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

  // Initialise and register projections
  declare(UnstableParticles(), "UFS");
  declare(FinalState(), "FS");

  for (double eVal : allowedEnergies()) {
    const string en = toString(round(eVal / MeV));
    if (isCompatibleWithSqrtS(eVal, 1e-3)) _sqs = en;
  }
  raiseBeamErrorIf(_sqs.empty());
  // Book histograms
  book(_h_N, 2, 1, 1);
  book(_h_N_Upsilon, 3, 1, 1);
  book(_h_tot_N, 4, 1, 1);
  book(_h_N_tot_Upsilon, 5, 1, 1);
  // counters for R
  book(_c_hadrons, "/TMP/sigma_hadrons");
  book(_c_muons, "/TMP/sigma_muons");
  book(_w_cont, "/TMP/w_cont");
  book(_w_ups, "/TMP/w_ups");
}

/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(const Particle& mother, unsigned int& nCharged) const {
  for (const Particle& p : mother.children()) {
    if (!p.children().empty()) {
      findDecayProducts(p, nCharged);
    }
    else if (PID::isCharged(p.pid())) {
      ++nCharged;
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");
  // Find the Upsilons among the unstables
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  Particles upsilons = ufs.particles(Cuts::pid == 300553);
  // Continuum
  if (upsilons.empty()) {
    map<long, int> nCount;
    int ntotal(0);
    unsigned int nCharged(0);
    for (const Particle& p : fs.particles()) {
      nCount[p.pid()] += 1;
      ++ntotal;
      if (PID::isCharged(p.pid())) ++nCharged;
    }
    // mu+mu- + photons
    if (_sqs == "9360"s && nCount[-13] == 1 && nCount[13] == 1 && ntotal == 2 + nCount[22]) {
      _c_muons->fill();
    }
    // everything else
    else {
      if (_sqs == "9360"s)
        _c_hadrons->fill();
      else if (_sqs == "10470"s) {
        _h_N->fill(nCharged);
        _h_tot_N->fill(Ecm1, nCharged);
        _w_cont->fill();
      }
    }
  }
  // upsilon 4s
  else if (_sqs == "10575"s) {
    for (const Particle& ups : upsilons) {
      unsigned int nCharged(0);
      findDecayProducts(ups, nCharged);
      _h_N_Upsilon->fill(nCharged);
      _h_N_tot_Upsilon->fill(Ecm2, nCharged);
      _w_ups->fill();
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // multi @ 9.36 GeV
  BinnedEstimatePtr<string> mult;
  book(mult, 1, 1, 1);
  if (_c_muons->val()) {
    Estimate0D R = *_c_hadrons / *_c_muons;
    mult->bin(1).set(R.val(), R.errPos());
  }
  // other energies
  normalize(_h_N, 100.);
  normalize(_h_N_Upsilon, 100.);
  if (_w_cont->val()) scale(_h_tot_N, 1.0 / *_w_cont);
  if (_w_ups->val()) scale(_h_N_tot_Upsilon, 1.0 / *_w_ups);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<int> _h_N, _h_N_Upsilon;
BinnedHistoPtr<string> _h_tot_N, _h_N_tot_Upsilon;
CounterPtr _c_hadrons, _c_muons, _w_cont, _w_ups;
const string Ecm1 = "10.47", Ecm2 = "10.575";
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1992_I319102);

} ```