Rivet analyses

title: BABAR_2017_I1511276

Cross section for $e^+e^-\to K_S^0K_L^0$ with $\pi^0$, $\eta$ and $\pi^0\pi^0$ between threshold and 4 GeV

Experiment: BABAR (PEP-II)

Inspire ID: 1511276

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev. D95 (2017) no.5, 052001

Beams: e+ e-

Beam energies: (0.6, 0.6); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.8, 0.8); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.4, 1.4); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.6, 1.6); (1.6, 1.6); (1.6, 1.6); (1.6, 1.6); (1.6, 1.6); (1.6, 1.6); (1.7, 1.7); (1.7, 1.7); (1.7, 1.7); (1.7, 1.7); (1.7, 1.7); (1.7, 1.7); (1.8, 1.8); (1.8, 1.8); (1.8, 1.8); (1.8, 1.8); (1.8, 1.8); (1.8, 1.8); (1.9, 1.9); (1.9, 1.9); (1.9, 1.9); (1.9, 1.9); (1.9, 1.9); (1.9, 1.9); (2.0, 2.0); (2.0, 2.0); (2.0, 2.0)GeV

Run details: - e+e- to hadrons

Cross section for $e^+e^-\to K_S^0K_L^0$ with $\pi^0$, $\eta$ and $\pi^0\pi^0$ between threshold and 4 GeV using radiative events.

Source code:BABAR_2017_I1511276.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e- -> K_S0K_L0 with pi0, eta and 2pi0 class BABAR_2017_I1511276 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2017_I1511276);


/// @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
  bool pass = false;
  for (size_t ix = 0; ix < _sqs.size(); ++ix) {
    book(_sigma[ix], 1 + ix, 1, 1);
    for (const string& en : _sigma[ix].binning().edges<0>()) {
      const double eval = std::stod(en);
      if (isCompatibleWithSqrtS(eval)) {
        _sqs[ix] = en;
        pass = true;
        break;
      }
    }
  }
  raiseBeamErrorIf(!pass);
}

void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) {
  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;
  }
  // stable histos
  if (ntotal == 3 && nCount[130] == 1 && nCount[310] == 1 && nCount[111] == 1) {
    if (!_sqs[0].empty()) _sigma[0]->fill(_sqs[0]);
  }
  else if (ntotal == 4 && nCount[130] == 1 && nCount[310] == 1 && nCount[111] == 2) {
    if (!_sqs[3].empty()) _sigma[3]->fill(_sqs[3]);
  }
  // unstable particles
  const FinalState& ufs = apply<FinalState>(event, "UFS");
  for (const Particle& p : ufs.particles()) {
    if (p.children().empty()) continue;
    if (p.pid() != 333 && p.pid() != 221) continue;
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(p, nRes, ncount);
    bool matched = true;
    if (p.pid() == 333 && ncount == 1) {
      for (const auto& val : nRes) {
        if (val.first == 111) {
          if (val.second != 1) {
            matched = false;
            break;
          }
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched) {
        if (!_sqs[1].empty()) _sigma[1]->fill(_sqs[1]);
      }
    }
    else if (p.pid() == 221 && ncount == 2) {
      for (const auto& val : nRes) {
        if (val.first == 130 || val.first == 310) {
          if (val.second != 1) {
            matched = false;
            break;
          }
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched) {
        if (!_sqs[2].empty()) _sigma[2]->fill(_sqs[2]);
      }
    }
  }
}


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

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _sigma[4];
vector<string> _sqs{""s, ""s, ""s, ""s};
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2017_I1511276);

} ```