Rivet analyses

title: BABAR_2006_I722905

Kinematic distributions in the decays $D^0\to K^\mp\pi^\pm\pi^0$

Experiment: BABAR (PEP-II)

Inspire ID: 722905

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 97 (2006) 221803

Beams: * *

Beam energies: ANY

Run details: - Any process producing D0

Kinematic distributions in the decays $D^0\to K^\mp\pi^\pm\pi^0$. Data read from plots

Source code:BABAR_2006_I722905.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief D0 -> K- pi+ pi0 (or CC) class BABAR_2006_I722905 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2006_I722905);


/// @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[ix], 1 + ix, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{-321, 1}, {211, 1}, {111, 1}};
  static const map<PdgId, unsigned int>& modeCC = {{321, 1}, {-211, 1}, {111, 1}};
  DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
  // loop over particles
  for (unsigned int ix = 0; ix < D0.decaying().size(); ++ix) {
    int sign = 1;
    if (D0.modeMatches(ix, 3, mode)) {
      sign = 1;
    }
    else if (D0.modeMatches(ix, 3, modeCC)) {
      sign = -1;
    }
    else
      continue;
    const Particle& pi0 = D0.decayProducts()[ix].at(111)[0];
    const Particle& Km = D0.decayProducts()[ix].at(-sign * 321)[0];
    double m2 = (pi0.momentum() + Km.momentum()).mass2();
    if ((D0.decaying()[ix].pid() > 0 && sign == 1) || (D0.decaying()[ix].pid() < 0 && sign == -1))
      _h[0]->fill(m2);
    else
      _h[1]->fill(m2);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 2; ++ix) normalize(_h[ix]);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[2];
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2006_I722905);

} ```