Rivet analyses

Mass distributions in χc → ϕKKπ 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 χc → ϕKKπ 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++ -*-
#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);

}