Rivet analyses

title: BESII_2007_I763880

Cross-sections for light hadrons at 3.773 and 3.650 GeV

Experiment: BESII (BEPC)

Inspire ID: 763880

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B670 (2008) 184-189, 2008

Beams: e+ e-

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

Run details: - e+e- to hadrons

Cross section for $e^+e^-\to \omega \pi^+\pi^-$, $\omega K^+K^-$, $\omega p\bar{p}$, $K^+K^-\rho^0\pi^0$, $K^+K^-\rho^+\pi^-+\text{c.c.}$, $K^{0}K^-\pi^+\pi^0+\text{c.c.}$ and $K^{+}K^-\pi^+\pi^-+\text{c.c.}$ at 3.773 and 3.650 GeV.

Source code:BESII_2007_I763880.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 and 3.650 GeV class BESII_2007_I763880 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2007_I763880);


/// @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
  for (size_t ix = 4; ix < 8; ++ix) {
    book(_nMeson[ix], 1, 1, ix);
  }

  for (const string& en : _nMeson[5].binning().edges<0>()) {
    const double eval = stod(en);
    if (isCompatibleWithSqrtS(eval)) {
      _sqs = en;
      break;
    }
  }
  raiseBeamErrorIf(_sqs.empty());
}


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() != 223 && p.pid() != 113 && p.abspid() != 313 && p.abspid() != 323) continue;
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(p, nRes, ncount);
    if (p.pid() == 113) {
      if (ncount != 3) continue;
      unsigned int npi(0), nK(0);
      bool matched = true;
      for (const auto& val : nRes) {
        if (abs(val.first) == 111 && val.second == 1) {
          npi += 1;
        }
        else if (abs(val.first) == 321 && val.second == 1) {
          nK += 1;
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched && npi == 1 && nK == 2 && _sqs == "3.65") _nMeson[4]->fill(_sqs);
    }
    else if (p.abspid() == 213) {
      if (ncount != 3) continue;
      unsigned int npi(0), nK(0);
      bool matched = true;
      int ipi = p.pid() == 213 ? -211 : 211;
      for (const auto& val : nRes) {
        if (abs(val.first) == ipi && val.second == 1) {
          npi += 1;
        }
        else if (abs(val.first) == 321 && val.second == 1) {
          nK += 1;
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched && npi == 1 && nK == 2) _nMeson[5]->fill(_sqs);
    }
    else if (p.abspid() == 313) {
      if (ncount != 3) continue;
      unsigned int npi(0), nK(0), npi0(0);
      bool matched = true;
      int ipi = p.pid() == 313 ? 211 : -211;
      int iK = p.pid() == 313 ? -321 : 321;
      for (const auto& val : nRes) {
        if (abs(val.first) == ipi && val.second == 1) {
          npi += 1;
        }
        else if (abs(val.first) == iK && val.second == 1) {
          nK += 1;
        }
        if (abs(val.first) == 111 && val.second == 1) {
          npi0 += 1;
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched && npi == 1 && nK == 1 && npi0 == 1) {
        _nMeson[6]->fill(_sqs);
      }
    }
    else if (p.abspid() == 323) {
      if (ncount != 3) continue;
      unsigned int npi(0), nK(0), npi0(0);
      bool matched = true;
      int ipi = p.pid() == 323 ? 211 : -211;
      int iK = p.pid() == 323 ? -321 : 321;
      for (const auto& val : nRes) {
        if (abs(val.first) == ipi && val.second == 1) {
          npi += 1;
        }
        else if (abs(val.first) == iK && val.second == 1) {
          nK += 1;
        }
        if (abs(val.first) == 111 && val.second == 1) {
          npi0 += 1;
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched && npi == 1 && nK == 1 && npi0 == 1) {
        _nMeson[7]->fill(_sqs);
      }
    }
  }
}


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

/// @}


/// @name Histograms
/// @{
map<int, BinnedHistoPtr<string>> _nMeson;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(BESII_2007_I763880);

} ```