Rivet analyses

title: UA5_1987_I244829

UA5 charged multiplicity measurements at 546 GeV

Experiment: UA5 (CERN SPS)

Inspire ID: 244829

Status: VALIDATED

Authors: - Holger Schulz

References: - Phys.Rept.154:247-383,1987

Beams: p- p+

Beam energies: (273.0, 273.0)GeV

Run details: - QCD and diffractive events at 546 GeV

Charged particle multiplicity measurement.

Source code:UA5_1987_I244829.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/TriggerUA5.hh"

namespace Rivet {

/// UA5 charged multiplicity measurements at 546 GeV class UA5_1987_I244829 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(UA5_1987_I244829);


/// Book histograms and initialise projections before the run
void init() {
  declare(TriggerUA5(), "Trigger");
  declare(ChargedFinalState(Cuts::abseta < 5.0), "CFS");

  book(_hist_mean_nch, 1, 1, 1);
  book(_hist_nch, 3, 1, 1);
  book(_sumWPassed, "SumW");

  vector<double> tmp;
  tmp.reserve(41);
  for (int i = 1; i < 41; ++i) tmp.push_back(2 * i - 1);
  tmp.push_back(82);
  _axis = YODA::Axis<double>(tmp);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) _edges = _hist_nch->xEdges();
  // Trigger
  const TriggerUA5& trigger = apply<TriggerUA5>(event, "Trigger");
  if (!trigger.nsdDecision()) vetoEvent;

  _sumWPassed->fill();

  // Count final state particles in several eta regions
  const int Nch = apply<ChargedFinalState>(event, "CFS").size();

  // Fill histograms
  _hist_nch->fill(map2string(Nch));
  _hist_mean_nch->fill(546, Nch);
}

string map2string(const size_t nch) const {
  if (82 <= nch && nch <= 84) return "82.0 - 84.0";
  if (86 <= nch && nch <= 88) return "86.0 - 88.0";
  if (90 <= nch && nch <= 92) return "90.0 - 92.0";
  if (94 <= nch && nch <= 96) return "94.0 - 96.0";
  if (98 <= nch && nch <= 100) return "98.0 - 100.0";
  if (102 <= nch && nch <= 110) return "102.0 - 110.0";
  if (112 <= nch && nch <= 120) return "112.0 - 120.0";
  const size_t idx = _axis.index(nch);
  if (idx && idx <= _edges.size()) return _edges[idx - 1];
  return "OTHER";
}


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

  scale(_hist_nch, 1.0 / *_sumWPassed);
  scale(_hist_mean_nch, 1.0 / *_sumWPassed);

  for (auto& b : _hist_nch->bins()) {
    const size_t idx = b.index();
    double sf = idx < 46 ? 2.0 : 8.0;
    if (idx == 40) sf = 3.0;
    b.scaleW(1.0 / sf);
  }
}

private:

CounterPtr _sumWPassed;

BinnedHistoPtr<int> _hist_mean_nch;
BinnedHistoPtr<string> _hist_nch;
vector<string> _edges;
YODA::Axis<double> _axis;

};

RIVET_DECLARE_ALIASED_PLUGIN(UA5_1987_I244829, UA5_1987_S1640666);

} ```

Aliases: - UA5_1987_S1640666