Rivet analyses

Dalitz plot analysis of D0 → KS0K±π∓

Experiment: CLEO (CESR)

Inspire ID: 1094160

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 85 (2012) 092016

Beams: * *

Beam energies: ANY

Run details: - Any process producing D0

Measurement of Kinematic distributions in the decays D0 → KS0K±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:CLEO_2012_I1094160.cc

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

namespace Rivet {


  /// @brief D0 -> KS0 K+/- pi-/+
  class CLEO_2012_I1094160 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2012_I1094160);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 421);
      declare(ufs, "UFS");
      DecayedParticles D0(ufs);
      D0.addStable(PID::PI0);
      D0.addStable(PID::K0S);
      D0.addStable(PID::ETA);
      D0.addStable(PID::ETAPRIME);
      declare(D0, "D0");
      // histograms
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_K0Km[ix], 1, 1, 1 + 3 * ix);
        book(_h_K0pip[ix], 1, 1, 2 + 3 * ix);
        book(_h_Kmpip[ix], 1, 1, 3 + 3 * ix);
        book(_h_K0Kp[ix], 2, 1, 1 + 3 * ix);
        book(_h_K0pim[ix], 2, 1, 2 + 3 * ix);
        book(_h_Kppim[ix], 2, 1, 3 + 3 * ix);
        book(_dalitz[ix], "dalitz_" + toString(ix + 1), 50, 0.3, 2.0, 50, 0.3, 2.);
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{321, 1}, {-211, 1}, {310, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{-321, 1}, {211, 1}, {310, 1}};
      DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
      // loop over particles
      for (unsigned int ix = 0; ix < D0.decaying().size(); ++ix) {
        if (!D0.modeMatches(ix, 3, mode) && !D0.modeMatches(ix, 3, modeCC)) continue;
        const Particles& K0 = D0.decayProducts()[ix].at(310);
        int sign = D0.decaying()[ix].pid() / 421;
        const Particles& pip = D0.decayProducts()[ix].find(sign * 211) == D0.decayProducts()[ix].end()
            ? Particles()
            : D0.decayProducts()[ix].at(sign * 211);
        const Particles& pim = D0.decayProducts()[ix].find(-sign * 211) == D0.decayProducts()[ix].end()
            ? Particles()
            : D0.decayProducts()[ix].at(-sign * 211);
        const Particles& Kp = D0.decayProducts()[ix].find(sign * 321) == D0.decayProducts()[ix].end()
            ? Particles()
            : D0.decayProducts()[ix].at(sign * 321);
        const Particles& Km = D0.decayProducts()[ix].find(-sign * 321) == D0.decayProducts()[ix].end()
            ? Particles()
            : D0.decayProducts()[ix].at(-sign * 321);
        // K0S K- pi+
        if (Km.size() == 1 && pip.size() == 1) {
          double mK0pip = (K0[0].momentum() + pip[0].momentum()).mass2();
          double mKmpip = (Km[0].momentum() + pip[0].momentum()).mass2();
          double mKK = (K0[0].momentum() + Km[0].momentum()).mass2();
          for (unsigned int ix = 0; ix < 2; ++ix) {
            _h_K0Km[ix]->fill(mKK);
            _h_K0pip[ix]->fill(mK0pip);
            _h_Kmpip[ix]->fill(mKmpip);
          }
          _dalitz[0]->fill(mKmpip, mK0pip);
        }
        // K0S K+ pi-
        else if (Kp.size() == 1 && pim.size() == 1) {
          double mK0pim = (K0[0].momentum() + pim[0].momentum()).mass2();
          double mKppim = (Kp[0].momentum() + pim[0].momentum()).mass2();
          double mKK = (K0[0].momentum() + Kp[0].momentum()).mass2();
          for (unsigned int ix = 0; ix < 2; ++ix) {
            _h_K0Kp[ix]->fill(mKK);
            _h_K0pim[ix]->fill(mK0pim);
            _h_Kppim[ix]->fill(mKppim);
          }
          _dalitz[1]->fill(mKppim, mK0pim);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 2; ++ix) {
        normalize(_h_K0Km[ix]);
        normalize(_h_K0pip[ix]);
        normalize(_h_Kmpip[ix]);
        normalize(_h_K0Kp[ix]);
        normalize(_h_K0pim[ix]);
        normalize(_h_Kppim[ix]);
        normalize(_dalitz[ix]);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_Kmpip[2], _h_K0pip[2], _h_K0Km[2];
    Histo1DPtr _h_Kppim[2], _h_K0pim[2], _h_K0Kp[2];
    Histo2DPtr _dalitz[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEO_2012_I1094160);

}