Rivet analyses

Dalitz plot analysis of D_s⁺ → π⁺π⁺π⁻

Experiment: BABAR (PEP-II)

Inspire ID: 792597

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 79 (2009) 032003

Beams: * *

Beam energies: ANY

Run details: - Any process producing D_s+ -> pi+ pi+ pi-

Measurement of the mass distributions in the decay D_s⁺ → π⁺π⁺π⁻. 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:`BABAR_2008_I792597.cc`

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

namespace Rivet {


  /// @brief D_s+ -> pi+pi+pi-
  class BABAR_2008_I792597 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I792597);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 431);
      declare(ufs, "UFS");
      DecayedParticles DS(ufs);
      DS.addStable(PID::PI0);
      DS.addStable(PID::K0S);
      declare(DS, "DS");
      // histos
      book(_h_pippim[0], 1, 1, 3);
      book(_h_pippip, 1, 1, 4);
      book(_h_pippim[1], 1, 1, 1);
      book(_h_pippim[2], 1, 1, 2);
      book(_dalitz, "dalitz", 50, 0., 3.5, 50, 0.0, 3.5);
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{211, 2}, {-211, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{-211, 2}, {211, 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& pip = DS.decayProducts()[ix].at(sign * 211);
        const Particle& pim = DS.decayProducts()[ix].at(-sign * 211)[0];
        // kinematic variables
        double x[3] = {(pim.momentum() + pip[0].momentum()).mass2(),
                       (pim.momentum() + pip[1].momentum()).mass2(),
                       (pip[0].momentum() + pip[1].momentum()).mass2()};
        if (x[0] > x[1]) swap(x[0], x[1]);
        _dalitz->fill(x[0], x[1]);
        _dalitz->fill(x[1], x[0]);
        // fill plots
        _h_pippim[0]->fill(x[0]);
        _h_pippim[0]->fill(x[1]);
        _h_pippim[1]->fill(x[0]);
        _h_pippim[2]->fill(x[1]);
        _h_pippip->fill(x[2]);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 3; ++ix) normalize(_h_pippim[ix]);
      normalize(_h_pippip);
      normalize(_dalitz);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_pippim[3], _h_pippip;
    Histo2DPtr _dalitz;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2008_I792597);

}

Rivet analyses

Dalitz plot analysis of Ds+ → π+π+π−

Source code:BABAR_2008_I792597.cc

Dalitz plot analysis of D_s⁺ → π⁺π⁺π⁻

Source code:`BABAR_2008_I792597.cc`