Rivet analyses

title: LENA_1982_I179431

Measurement of $R$ between 7.4 and 9.4 GeV

Experiment: LENA (DORIS)

Inspire ID: 179431

Status: VALIDATED

Authors: - Peter Richardson

References: - Z.Phys. C15 (1982) 299, 1982

Beams: e- e+

Beam energies: (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (3.7, 3.7); (4.3, 4.3); (4.3, 4.3); (4.3, 4.3); (4.3, 4.3); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.4, 4.4); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.5, 4.5); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.6, 4.6); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7); (4.7, 4.7)GeV

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

Measurement of $R$ in $e^+e^-$ collisions by LENA for energies between .4 and 9.4 GeV. 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:LENA_1982_I179431.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief R measurement class LENA_1982_I179431 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LENA_1982_I179431);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(FinalState(), "FS");

  // Book histograms
  for (size_t i = 0; i < 2; ++i) {
    const auto& ref = refData(i + 1, 1, 1);
    book(_h_hadrons[i], "d0" + to_string(i + 1) + "_sigma_hadrons", ref);
    book(_h_muons[i], "d0" + to_string(i + 1) + "_sigma_muons", ref);
  }
  const auto& ref = refData<YODA::BinnedEstimate<string>>(3, 1, 1);
  book(_c_hadrons, "d03_sigma_hadrons", ref);
  book(_c_muons, "d03_sigma_muons", ref);
  for (const string& en : _c_hadrons.binning().edges<0>()) {
    double eval = stod(en);
    if (isCompatibleWithSqrtS(eval)) {
      _sqs = en;
      break;
    }
  }
  raiseBeamErrorIf(_sqs.empty() && !inRange(sqrtS() / GeV, 7.4, 9.43));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");

  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
  }
  // mu+mu- + photons
  if (nCount[-13] == 1 and nCount[13] == 1 && ntotal == 2 + nCount[22]) {
    _h_muons[0]->fill(sqrtS() / GeV);
    _h_muons[1]->fill(sqrtS() / GeV);
    _c_muons->fill(_sqs);
  }
  // everything else
  else {
    _h_hadrons[0]->fill(sqrtS() / GeV);
    _h_hadrons[1]->fill(sqrtS() / GeV);
    _c_hadrons->fill(_sqs);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale({_c_hadrons, _c_muons}, crossSectionPerEvent());
  scale(_h_hadrons, crossSectionPerEvent());
  scale(_h_muons, crossSectionPerEvent());
  for (size_t ix = 0; ix < 2; ++ix) {
    Estimate1DPtr mult;
    book(mult, ix + 1, 1, 1);
    divide(_h_hadrons[ix], _h_muons[ix], mult);
  }
  BinnedEstimatePtr<string> mult;
  book(mult, 3, 1, 1);
  divide(_c_hadrons, _c_muons, mult);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _c_hadrons, _c_muons;
Histo1DPtr _h_hadrons[2], _h_muons[2];
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(LENA_1982_I179431);

} ```