Rivet analyses

χ_c0 → π⁺π⁻K⁺K⁻

Experiment: BESII (BEPC)

Inspire ID: 690784

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 72 (2005) 092002

Beams: * *

Beam energies: ANY

Run details: - Any process producing chi_c0

Measurement of the mass distributions in the decays χ_c0 → π⁺π⁻K⁺K⁻. The data were read from the plots in the paper and may not be corrected for backgrounds and efficiency.

Source code:`BESII_2005_I690784.cc`

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief chi_c0 -> pi+ pi- K+ K-
  class BESII_2005_I690784 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2005_I690784);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::pid == 10441);
      declare(ufs, "UFS");
      DecayedParticles chi(ufs);
      chi.addStable(PID::PI0);
      chi.addStable(PID::K0S);
      chi.addStable(PID::ETA);
      declare(chi, "chi");
      for (unsigned int ix = 0; ix < 4; ++ix) book(_h[ix], 1, 1, ix + 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{211, 1}, {-211, 1}, {321, 1}, {-321, 1}};
      DecayedParticles chi = apply<DecayedParticles>(event, "chi");
      // loop over particles
      for (unsigned int ix = 0; ix < chi.decaying().size(); ++ix) {
        if (!chi.modeMatches(ix, 4, mode1)) continue;
        const Particle& pim = chi.decayProducts()[ix].at(-211)[0];
        const Particle& pip = chi.decayProducts()[ix].at(211)[0];
        const Particle& Km = chi.decayProducts()[ix].at(-321)[0];
        const Particle& Kp = chi.decayProducts()[ix].at(321)[0];
        _h[0]->fill((Km.momentum() + Kp.momentum()).mass());
        _h[1]->fill((pim.momentum() + pip.momentum()).mass());
        _h[2]->fill((Km.momentum() + pip.momentum()).mass());
        _h[2]->fill((Kp.momentum() + pim.momentum()).mass());
        _h[3]->fill((Km.momentum() + pip.momentum() + pim.momentum()).mass());
        _h[3]->fill((Kp.momentum() + pim.momentum() + pip.momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 4; ++ix) normalize(_h[ix]);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[4];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BESII_2005_I690784);

}

Rivet analyses

χc0 → π+π−K+K−

Source code:BESII_2005_I690784.cc

χ_c0 → π⁺π⁻K⁺K⁻

Source code:`BESII_2005_I690784.cc`