Rivet analyses

Dalitz plot analysis of D+ → K+K−π+

Experiment: BABAR (PEP-II)

Inspire ID: 1206605

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 87 (2013) 5, 052010

Beams: * *

Beam energies: ANY

Run details: - Any process producing D0

Kinematic distributions in the decay D+ →  → K+K−π+. 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_2013_I1206605.cc

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

namespace Rivet {


  /// @brief  D+ -> K+K-pi+
  class BABAR_2013_I1206605 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2013_I1206605);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 411);
      declare(ufs, "UFS");
      DecayedParticles DP(ufs);
      DP.addStable(PID::PI0);
      DP.addStable(PID::K0S);
      DP.addStable(PID::ETA);
      DP.addStable(PID::ETAPRIME);
      declare(DP, "DP");
      // histos
      book(_h_Kppi, 1, 1, 1);
      book(_h_KK, 1, 1, 2);
      book(_h_Kmpi, 1, 1, 3);
      book(_dalitz, "dalitz", 50, 0., 2., 50, 0.9, 3.1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{321, 1}, {-321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{321, 1}, {-321, 1}, {-211, 1}};
      DecayedParticles DP = apply<DecayedParticles>(event, "DP");
      // loop over particles
      for (unsigned int ix = 0; ix < DP.decaying().size(); ++ix) {
        int sign = 1;
        if (DP.decaying()[ix].pid() > 0 && DP.modeMatches(ix, 3, mode)) {
          sign = 1;
        }
        else if (DP.decaying()[ix].pid() < 0 && DP.modeMatches(ix, 3, modeCC)) {
          sign = -1;
        }
        else
          continue;
        const Particle& Kp = DP.decayProducts()[ix].at(sign * 321)[0];
        const Particle& Km = DP.decayProducts()[ix].at(-sign * 321)[0];
        const Particle& pip = DP.decayProducts()[ix].at(sign * 211)[0];
        double mminus = (Km.momentum() + pip.momentum()).mass2();
        double mplus = (Kp.momentum() + pip.momentum()).mass2();
        double mKK = (Kp.momentum() + Km.momentum()).mass2();
        _h_Kppi->fill(mplus);
        _h_Kmpi->fill(mminus);
        _h_KK->fill(mKK);
        _dalitz->fill(mminus, mKK);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h_Kppi);
      normalize(_h_Kmpi);
      normalize(_h_KK);
      normalize(_dalitz);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_Kppi, _h_Kmpi, _h_KK;
    Histo2DPtr _dalitz;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2013_I1206605);

}