Rivet analyses

Pion mass distribution in ψ(2S) → ππJ/ψ

Experiment: CLEOC (CESR)

Inspire ID: 784516

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 78 (2008) 011102

Beams: * *

Beam energies: ANY

Run details: - Any process producing psi(2S)

Measurement of the mass distribution in ψ(2S) → π⁺π⁻J/ψ and π⁰π⁰J/ψ decays by CLEO. THe data were read from the plots in the paper and may not be corrected for efficiency/acceptance.

Source code:`CLEOC_2008_I784516.cc`

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

namespace Rivet {


  /// @brief  psi(2S) -> J/Psi pi pi
  class CLEOC_2008_I784516 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOC_2008_I784516);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::pid == 100443);
      declare(ufs, "UFS");
      DecayedParticles psi(ufs);
      psi.addStable(PID::PI0);
      psi.addStable(PID::JPSI);
      declare(psi, "psi");
      for (unsigned int ix = 0; ix < 2; ++ix) book(_h[ix], 1, 1, 1 + ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{211, 1}, {-211, 1}, {443, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{111, 2}, {443, 1}};
      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
      // loop over particles
      for (unsigned int ix = 0; ix < psi.decaying().size(); ++ix) {
        if (psi.modeMatches(ix, 3, mode1)) {
          const Particle& pip = psi.decayProducts()[ix].at(211)[0];
          const Particle& pim = psi.decayProducts()[ix].at(-211)[0];
          _h[0]->fill((pip.momentum() + pim.momentum()).mass());
        }
        else if (psi.modeMatches(ix, 3, mode2)) {
          const Particles& pi0 = psi.decayProducts()[ix].at(111);
          _h[1]->fill((pi0[0].momentum() + pi0[1].momentum()).mass());
        }
      }
    }


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

    /// @}


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


  RIVET_DECLARE_PLUGIN(CLEOC_2008_I784516);

}

Rivet analyses

Pion mass distribution in ψ(2S) → ππJ/ψ

Source code:CLEOC_2008_I784516.cc

Source code:`CLEOC_2008_I784516.cc`