Rivet analyses

title: BELLE_2014_I1309588

Cross section for $e^+e^-\to\pi^+\pi^-\pi^0\chi_{b(1,2)}$ for $\sqrt{s}=10.867$ GeV

Experiment: BELLE (KEKB)

Inspire ID: 1309588

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 113 (2014) 14, 142001

Beams: e+ e-

Beam energies: (5.4, 5.4)GeV

Run details: - e+ e- -> hadrons, KS0 and pi0 set stable

Measurement ofr the ross section for $e^+e^-\to\pi^+\pi^-\pi^0\chi_{b(1,2)}$ for $\sqrt{s}=10.867$ GeV. The $\omega$ and non-$\omega$ contributions are also measured.

Source code:BELLE_2014_I1309588.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+ e- > pi+ pi- pi0 chi_b class BELLE_2014_I1309588 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2014_I1309588);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  declare(FinalState(), "FS");
  declare(UnstableParticles(), "UFS");
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      book(_h[ix][iy], 1 + ix, 1, 1 + iy);
    }
  }
}

void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) {
  for (const Particle& child : p.children()) {
    if (child.children().empty()) {
      --nRes[child.pid()];
      --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");
  // loop over any chi mesons
  for (const Particle& chi : ufs.particles(Cuts::pid == 20553 || Cuts::pid == 555)) {
    if (chi.children().empty()) continue;
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(chi, nRes, ncount);
    // first check for 3 pi chi_b
    bool matched3Pi = false;
    if (ncount == 3) {
      matched3Pi = true;
      for (const auto& val : nRes) {
        if (abs(val.first) == PID::PIPLUS || val.first == PID::PI0) {
          if (val.second != 1) {
            matched3Pi = false;
            break;
          }
        }
        else if (val.second != 0) {
          matched3Pi = false;
          break;
        }
      }
    }
    // then for omega chi_b
    bool matchedOmega = false;
    for (const Particle& omega : ufs.particles(Cuts::pid == 223)) {
      Particle parent = omega;
      while (!parent.parents().empty()) {
        parent = parent.parents()[0];
        if (parent.pid() == 555 || parent.pid() == 20553) break;
      }
      if ((parent.pid() == 555 || parent.pid() == 20553)
          && fuzzyEquals(parent.momentum(), chi.momentum()))
        continue;
      map<long, int> nRes2 = nRes;
      int ncount2 = ncount;
      findChildren(omega, nRes2, ncount2);
      matchedOmega = true;
      for (const auto& val : nRes2) {
        if (val.second != 0) {
          matchedOmega = false;
          break;
        }
      }
      if (matchedOmega) break;
    }
    if (!matched3Pi && !matchedOmega) continue;
    unsigned int iloc = chi.pid() == 20553 ? 0 : 1;
    if (matched3Pi) {
      _h[0][iloc]->fill("10.867"s);
    }
    if (matchedOmega) {
      _h[1][iloc]->fill("10.867"s);
    }
    if (matched3Pi && !matchedOmega) {
      _h[2][iloc]->fill("10.867"s);
    }
    break;
  }
}

/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 3; ++ix) {
    scale(_h[ix], crossSection() / sumOfWeights() / picobarn);
  }
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _h[3][2];
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2014_I1309588);

} ```