Rivet analyses

Mass distributions in the decay D⁰ → K⁺K⁻π⁺π⁻

Experiment: FOCUS (Fermilab)

Inspire ID: 663820

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 610 (2005) 225-234

Beams: * *

Beam energies: ANY

Run details: none listed

Measurement of the mass distributions in the decay D⁰ → K⁺K⁻π⁺π⁻ by FOCUS. The data were read from the plots in the paper and therefore for some points the error bars are the size of the point. It is also not clear that any resolution effects have been unfolded.

Source code:`FOCUS_2004_I663820.cc`

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

namespace Rivet {


  /// @brief D0 -> K+ K- pi+ pi-
  class FOCUS_2004_I663820 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(FOCUS_2004_I663820);


    /// @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<4;++ix)
    book(_h[ix],1,1,1+ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // define the decay mode
      static const map<PdgId,unsigned int> & mode   = { { 321,1},{ -321,1}, { 211,1}, { -211,1}};
      DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
      // loop over particles
      for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
    if ( !D0.modeMatches(ix,4,mode)) continue;
    int sign = D0.decaying()[ix].pid()/421;
    const Particles & Kp = D0.decayProducts()[ix].at( sign*321);
    const Particles & Km = D0.decayProducts()[ix].at(-sign*321);
    const Particles & pip= D0.decayProducts()[ix].at( sign*211);
    const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
    _h[0]->fill((Kp [0].momentum()+Km [0].momentum()).mass());
    _h[1]->fill((pip[0].momentum()+pim[0].momentum()).mass());
    _h[2]->fill((Kp [0].momentum()+pim[0].momentum()).mass());
    _h[2]->fill((Km [0].momentum()+pip[0].momentum()).mass());
    _h[3]->fill((Kp [0].momentum()+pip[0].momentum()).mass());
    _h[3]->fill((Km [0].momentum()+pim[0].momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<4;++ix)
    normalize(_h[ix],1.,false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[4];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(FOCUS_2004_I663820);

}

Rivet analyses

Mass distributions in the decay D0 → K+K−π+π−

Source code:FOCUS_2004_I663820.cc

Mass distributions in the decay D⁰ → K⁺K⁻π⁺π⁻

Source code:`FOCUS_2004_I663820.cc`