Rivet analyses

title: BESII_2007_I750713

Cross-sections for light hadrons at 3.773, 3.650 GeV

Experiment: BESII (BEPC II)

Inspire ID: 750713

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B650 (2007) 111-118, 2007

Beams: e+ e-

Beam energies: (1.9, 1.9); (1.8, 1.8)GeV

Run details: - e+e- to hadrons

Cross section for $e^+e^-\to 2\pi^+2\pi^-$, $K^+K^-\pi^+\pi^-$, $2K^+2K^-$, $\phi K^+K^-$, $p\bar{p}\pi^+\pi^-$, $p\bar{p}K^+K^-$, $3\pi^+3\pi^-$, $2\pi^+2\pi^-\eta$, $2\pi^+2\pi^-\pi^0$, $K^+K^-\pi^+\pi^-\pi^0$, $2K^+2K^-\pi^0$, $p\bar{p}\pi^0$, $p\bar{p}\pi^+\pi^-\pi^0$, $3\pi^+3\pi^-\pi^0$ at 3.773 and 3.650 GeV.

Source code:BESII_2007_I750713.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Cross-sections for light hadrons at 3.773, 3.650 GeV class BESII_2007_I750713 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2007_I750713);


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

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

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

  // Book histograms
  _sqs = -1;
  if (isCompatibleWithSqrtS(3.65))
    _sqs = 100;
  else if (isCompatibleWithSqrtS(3.773))
    _sqs = 0;
  raiseBeamErrorIf(_sqs < 0);

  for (size_t ix = 3; ix < 19; ++ix) {
    if (ix == 5 || ix == 10) continue;
    book(_nMeson[ix], "TMP/n"s + toString(ix));
    book(_nMeson[ix + 100], "TMP/n"s + toString(ix + 100));
  }
}


void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) const {
  for (const Particle& child : p.children()) {
    if (child.children().empty()) {
      nRes[child.pid()] -= 1;
      --ncount;
    }
    else {
      findChildren(child, nRes, ncount);
    }
  }
}


/// 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;
  }
  const FinalState& ufs = apply<FinalState>(event, "UFS");

  for (const Particle& p : ufs.particles()) {
    if (p.children().empty()) continue;
    if (p.pid() != 221 && p.pid() != 333) continue;
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(p, nRes, ncount);
    // eta
    if (p.pid() == 221) {
      if (ncount == 4) {
        bool matched = true;
        for (const auto& val : nRes) {
          if (abs(val.first) == 211) {
            if (val.second != 2) {
              matched = false;
              break;
            }
          }
          else if (val.second != 0) {
            matched = false;
            break;
          }
        }
        if (matched) _nMeson[12 + _sqs]->fill();
      }
    }
    else if (p.pid() == 333) {
      if (ncount != 1) continue;
      bool matched = true;
      for (const auto& val : nRes) {
        if (abs(val.first) == 321) {
          if (val.second != 1) {
            matched = false;
            break;
          }
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched) _nMeson[7 + _sqs]->fill();
    }
  }
  if (ntotal == 3 && nCount[111] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
    _nMeson[16 + _sqs]->fill();
  else if (ntotal == 4) {
    if (nCount[-211] == 2 && nCount[211] == 2)
      _nMeson[3 + _sqs]->fill();
    else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-321] == 1 && nCount[321] == 1)
      _nMeson[4 + _sqs]->fill();
    else if (nCount[-321] == 2 && nCount[321] == 2)
      _nMeson[6 + _sqs]->fill();
    else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
      _nMeson[8 + _sqs]->fill();
    else if (nCount[-321] == 1 && nCount[321] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
      _nMeson[9 + _sqs]->fill();
  }
  else if (ntotal == 5 && nCount[111] == 1) {
    if (nCount[-211] == 2 && nCount[211] == 2)
      _nMeson[13 + _sqs]->fill();
    else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-321] == 1 && nCount[321] == 1)
      _nMeson[14 + _sqs]->fill();
    else if (nCount[-321] == 2 && nCount[321] == 2)
      _nMeson[15 + _sqs]->fill();
    else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
      _nMeson[17 + _sqs]->fill();
  }
  else if (ntotal == 6 && nCount[211] == 3 && nCount[-211] == 3)
    _nMeson[11 + _sqs]->fill();
  else if (ntotal == 7 && nCount[111] == 1 && nCount[211] == 3 && nCount[-211] == 3)
    _nMeson[18 + _sqs]->fill();
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_nMeson, crossSection() / sumOfWeights() / picobarn);
  BinnedEstimatePtr<string> mult;
  for (unsigned int ix = 3; ix < 19; ++ix) {
    if (ix == 5 || ix == 10) continue;
    book(mult, 1, 1, ix);
    mult->bin(1).set(_nMeson[ix]->val(), _nMeson[ix]->err());
    if (ix != 15) mult->bin(2).set(_nMeson[ix + 100]->val(), _nMeson[ix + 100]->err());
  }
}
/// @}


/// @name Histograms
/// @{
map<int, CounterPtr> _nMeson;
int _sqs;
/// @}

};

RIVET_DECLARE_PLUGIN(BESII_2007_I750713);

} ```