Rivet analyses

Pion mass distribution in Ds+ → ωπ+π0

Experiment: CLEO (CESR)

Inspire ID: 822856

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 80 (2009) 051102

Beams: * *

Beam energies: ANY

Run details: - Any process producing D_s+

Measurement of the pion mass distribution in Ds+ → ωπ+π0. The data were read from the plots in the paper. Resolution/acceptance effects have been not unfolded. Given the agreement with the model in the paper this analysis should only be used for qualitative studies.

Source code:CLEO_2009_I822856.cc

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

namespace Rivet {


  /// @brief D_s+ -> omega pi+ pi0
  class CLEO_2009_I822856 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2009_I822856);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 431);
      declare(ufs, "UFS");
      DecayedParticles DS(ufs);
      DS.addStable(PID::PI0);
      DS.addStable(PID::K0S);
      DS.addStable(PID::ETA);
      DS.addStable(PID::OMEGA);
      DS.addStable(PID::ETAPRIME);
      declare(DS, "DS");
      // histograms
      book(_h_pipi, 1, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{211, 1}, {111, 1}, {223, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{-211, 1}, {111, 1}, {223, 1}};
      DecayedParticles DS = apply<DecayedParticles>(event, "DS");
      // loop over particles
      for (unsigned int ix = 0; ix < DS.decaying().size(); ++ix) {
        int sign = 1;
        if (DS.decaying()[ix].pid() > 0 && DS.modeMatches(ix, 3, mode)) {
          sign = 1;
        }
        else if (DS.decaying()[ix].pid() < 0 && DS.modeMatches(ix, 3, modeCC)) {
          sign = -1;
        }
        else
          continue;
        const Particles& pi0 = DS.decayProducts()[ix].at(111);
        const Particles& pip = DS.decayProducts()[ix].at(sign * 211);
        _h_pipi->fill((pi0[0].momentum() + pip[0].momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h_pipi, 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_pipi;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEO_2009_I822856);

}