Rivet analyses

title: BESII_2008_I801208

Cross-sections for light hadrons at 3.773 and 3.650 GeV

Experiment: BESII (BEPC II)

Inspire ID: 801208

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B670 (2008) 179-183, 2008

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons

Cross section for $e^+e^-\to K^-\pi^+$, $K^-\pi^+\pi^0$, $K^-\pi^+\pi^+\pi^-$, $K^-\pi^+\pi^+\pi^-\pi^0$ and $K^-\pi^+\pi^0\pi^0$ together with a $K_S^0$ meson at 3.773 and 3.650 GeV.

Source code:BESII_2008_I801208.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief Cross-sections for light hadrons at 3.773 and 3.650 GeV class BESII_2008_I801208 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2008_I801208);


/// @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 ix = 1; ix < 7; ++ix) {
    book(_nMeson[ix], 1, 1, ix);
  }
  for (const string& en : _nMeson[2].binning().edges<0>()) {
    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& fs = apply<FinalState>(event, "FS");

  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
  }
  if (nCount[310] != 1) vetoEvent;

  if (ntotal == 3) {
    if ((nCount[211] == 1 && nCount[-321] == 1) || (nCount[-211] == 1 && nCount[321] == 1)) {
      if (_sqs == "3.773"s) _nMeson[1]->fill(_sqs);
    }
  }
  else if (ntotal == 4 && nCount[111] == 1) {
    if ((nCount[211] == 1 && nCount[-321] == 1) || (nCount[-211] == 1 && nCount[321] == 1))
      _nMeson[2]->fill(_sqs);
  }
  else if (ntotal == 5) {
    if ((nCount[211] == 2 && nCount[-211] == 1 && nCount[-321] == 1)
        || (nCount[-211] == 2 && nCount[211] == 1 && nCount[321] == 1))
      _nMeson[3]->fill(_sqs);
    if (((nCount[211] == 1 && nCount[-321] == 1) || (nCount[-211] == 1 && nCount[321] == 1))
        && nCount[111] == 2)
      _nMeson[6]->fill(_sqs);
  }
  else if (ntotal == 6 && nCount[111] == 1) {
    if ((nCount[211] == 2 && nCount[-211] == 1 && nCount[-321] == 1)
        || (nCount[-211] == 2 && nCount[211] == 1 && nCount[321] == 1))
      _nMeson[4]->fill(_sqs);
  }
  else if (ntotal == 7) {
    if ((nCount[211] == 3 && nCount[-211] == 2 && nCount[-321] == 1)
        || (nCount[-211] == 3 && nCount[211] == 2 && nCount[321] == 1)) {
      if (_sqs == "3.773"s) _nMeson[5]->fill(_sqs);
    }
  }
}

/// Normalise histograms etc., after the run
void finalize() {
  scale(_nMeson, crossSection() / sumOfWeights() / picobarn);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _nMeson[7];
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(BESII_2008_I801208);

} ```