Rivet analyses

title: CLEO_2012_I1094160

Dalitz plot analysis of $D^0\to K^0_SK^\pm\pi^\mp$

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 $D^0\to K^0_SK^\pm\pi^\mp$. 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++ // -- 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);

} ```