Rivet analyses

title: BESIII_2015_I1352828

Mass distributions in $\chi_c\to\phi K K \pi$ decays

Experiment: BESIII (BEPC)

Inspire ID: 1352828

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 91 (2015) 11, 112008

Beams: * *

Beam energies: ANY

Run details: - Any process producing chi_cJ, originally e+e-

Measurements of mass distributions in $\chi_c\to\phi K K \pi$ decays. The data were read from the plots in the paper and may not be corrected for efficiency

Source code:BESIII_2015_I1352828.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief chi_c -> phi K K pi class BESIII_2015_I1352828 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2015_I1352828);


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

/// Book histograms and initialise projections before the run
void init() {
  UnstableParticles ufs = UnstableParticles(Cuts::pid == 10441 or Cuts::pid == 20443 or Cuts::pid == 445);
  declare(ufs, "UFS");
  DecayedParticles chi(ufs);
  chi.addStable(PID::PHI);
  chi.addStable(PID::K0S);
  chi.addStable(PID::PI0);
  declare(chi, "chi");
  // histos
  for (unsigned int iy = 0; iy < 2; ++iy)
    for (unsigned int ix = 0; ix < 3; ++ix) book(_h[iy][ix], 1, 1 + iy, 1 + ix);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{333, 1}, {310, 1}, {321, 1}, {-211, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{333, 1}, {310, 1}, {-321, 1}, {211, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{333, 1}, {321, 1}, {-321, 1}, {111, 1}};
  DecayedParticles chi = apply<DecayedParticles>(event, "chi");
  for (unsigned int ix = 0; ix < chi.decaying().size(); ++ix) {
    int imode = 0;
    if (chi.modeMatches(ix, 4, mode1) || chi.modeMatches(ix, 4, mode1CC))
      imode = 0;
    else if (chi.modeMatches(ix, 4, mode2))
      imode = 1;
    else
      continue;
    unsigned int ichi = 0;
    if (chi.decaying()[ix].pid() == 20443)
      ichi = 1;
    else if (chi.decaying()[ix].pid() == 445)
      ichi = 2;
    const Particle& phi = chi.decayProducts()[ix].at(333)[0];
    double mass = (chi.decaying()[ix].momentum() - phi.momentum()).mass();
    _h[imode][ichi]->fill(mass);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int iy = 0; iy < 2; ++iy)
    for (unsigned int ix = 0; ix < 3; ++ix) normalize(_h[iy][ix], 1., false);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[2][3];
/// @}

};

RIVET_DECLARE_PLUGIN(BESIII_2015_I1352828);

} ```