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Rivet analyses reference

MC_D_Dalitz

MC analysis of Dalitz plots in three-body $D$-meson decays
Experiment: ()
Status: VALIDATED
Authors:
  • Peter Richardson
No references listed
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing D mesons

Monte Carlo analysis of $D^0\to \bar{K}^0\pi^+\pi^-$, $D^0\to K^-\pi^+\pi^0$, $D^+\to K^-\pi^+\pi^+$, $D^+\to\bar{K}^0\pi^+\pi^0$, $D^+\to K^+\pi^-\pi^+$ and $D_s^+\to K^+\pi^-\pi^+$ including kinematic distributions and Dalitz plots.

Source code: MC_D_Dalitz.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief Add a short analysis description here
  class MC_D_Dalitz : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(MC_D_Dalitz);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(UnstableParticles(), "UFS");

      // Book histograms
      book(_h_plus1, "h_plus1"   ,200,0.,3. );
      book(_h_minus1, "h_minus1"  ,200,0.,3.2 );
      book(_h_pipi1, "h_pipi1"   ,200,0.,2. );
      book(_h_minus2, "h_minus2"  ,200,0.,3.2 );
      book(_h_neutral2, "h_neutral2",200,0.,3.2 );
      book(_h_pipi2, "h_pipi2"   ,200,0.,2. );
      book(_h_Kpilow3, "h_Kpilow3"  ,200,0.,2. );
      book(_h_Kpihigh3, "h_Kpihigh3" ,200,0.,3.2 );
      book(_h_Kpiall3, "h_Kpiall3"  ,200,0.,3. );
      book(_h_pipi3, "h_pipi3"    ,200,0.,2. );
      book(_h_Kpip4, "h_Kpip4"   ,200,0.,3.2 );
      book(_h_pipi4, "h_pipi4"   ,200,0.,2. );
      book(_h_Kpi04, "h_Kpi04"   ,200,0.,3.2);
      book(_h_kppim5, "h_kppim5"   ,200,0.,3. );
      book(_h_kppip5, "h_kppip5"   ,200,0.,3.1 );
      book(_h_pippim5, "h_pippim5"  ,200,0.,2. );
      book(_h_kppim6, "h_kppim6"   ,200,0.,3.5);
      book(_h_kppip6, "h_kppip6"   ,200,0.,3.5);
      book(_h_pippim6, "h_pippim6"  ,200,0.,2.5);
      book(_dalitz1, "dalitz1"    ,50,0.3,3.2,50,0.3,3.2);
      book(_dalitz2, "dalitz2"    ,50,0.3,3. ,50,0.3,3. );
      book(_dalitz3, "dalitz3"    ,50,0.3,2. ,50,0.07,2. );
      book(_dalitz4, "dalitz4"    ,50,0.3,3.1 ,50,0.07,2. );
      book(_dalitz5, "dalitz5"    ,50,0.,3. ,50,0.,2. );
      book(_dalitz6, "dalitz6"    ,50,0.3,3.5,50,0.07,2.5);
    }

    void findDecayProducts(const Particle & mother, unsigned int & nstable,
			   Particles & pip , Particles & pim , Particles & pi0  ,
			   Particles & Kp  , Particles & Km  , Particles & K0) {
      for(const Particle & p : mother.children()) {
        int id = p.pid();
        if ( id == PID::KPLUS ) {
       	  Kp.push_back(p);
	  ++nstable;
	}
	else if (id == PID::KMINUS ) {
	  Km.push_back(p);
	  ++nstable;
	}
	else if (id == PID::PIPLUS) {
	  pip.push_back(p);
	  ++nstable;
	}
	else if (id == PID::PIMINUS) {
	  pim.push_back(p);
	  ++nstable;
	}
	else if (id == PID::PI0) {
	  pi0.push_back(p);
	  ++nstable;
	}
	else if (id == PID::K0S||id == PID::K0L) {
	  K0.push_back(p);
          ++nstable;
        }
	else if ( !p.children().empty() ) {
	  findDecayProducts(p, nstable, pip, pim, pi0, Kp , Km, K0);
	}
	else
	  ++nstable;
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      for(const Particle& meson : apply<UnstableParticles>(event, "UFS").
	    particles(Cuts::abspid== 411 ||Cuts::abspid== 421 ||Cuts::abspid== 431 )) {
	unsigned int nstable(0);
	Particles pip, pim, pi0, Kp , Km, K0;
	findDecayProducts(meson, nstable, pip, pim, pi0, Kp , Km, K0);
	if(meson.pid()<0) {
	  swap(pim,pip);
	  swap(Kp,Km);
	}
	if(abs(meson.pid())==421) {
	  if(pim.size()==1&&pip.size()==1&&K0.size()==1) {
	    double mminus = (pim[0].momentum()+K0[0].momentum() ).mass2();
	    double mplus  = (pip[0].momentum()+K0[0].momentum() ).mass2();
	    double mpipi  = (pip[0].momentum()+pim[0].momentum()).mass2();
	    _h_plus1  ->fill(mplus);
	    _h_minus1 ->fill(mminus);
	    _h_pipi1  ->fill(mpipi);
	    _dalitz1   ->fill(mplus,mminus);
	  }
	  else if (pip.size()==1&&Km.size()==1&&pi0.size()==1) {
	    double mneut  = (Km[0].momentum()+pip[0].momentum()).mass2();
	    double mminus = (Km[0].momentum()+pi0[0].momentum()).mass2();
	    double mpipi  = (pip[0].momentum()+pi0[0].momentum()).mass2();
	    _h_neutral2  ->fill(mneut);
	    _h_minus2 ->fill(mminus);
	    _h_pipi2  ->fill(mpipi);
	    _dalitz2->fill(mminus,mneut);
	  }
	}
	else if(abs(meson.pid())==411) {
	  if(pip.size()==2&&Km.size()==1) {
	    double mplus  = (Km[0].momentum() +pip[0].momentum()).mass2();
	    double mminus = (Km[0].momentum() +pip[1].momentum()).mass2();
	    double mpipi  = (pip[0].momentum()+pip[1].momentum()).mass2();
	    if(mplus<mminus) swap(mplus,mminus);
	    _h_Kpilow3 ->fill( mminus);
	    _h_Kpihigh3->fill( mplus);
	    _h_Kpiall3 ->fill( mminus);
	    _h_Kpiall3 ->fill( mplus);
	    _h_pipi3   ->fill( mpipi);
	    _dalitz3->fill(mminus,mpipi);
	  }
	  else if (pip.size()==1&&pi0.size()==1&&K0.size()==1) {
	    double mminus = (K0[0].momentum()+pip[0].momentum()).mass2();
	    double mplus  = (K0[0].momentum()+pi0[0].momentum()).mass2();
	    double mpipi  = (pip[0].momentum()+pi0[0].momentum()).mass2();
	    _h_Kpip4 ->fill( mminus);
	    _h_pipi4 ->fill( mpipi );
	    _h_Kpi04 ->fill( mplus );
	    _dalitz4->fill(mplus,mpipi);
	  }
	  else if (pim.size()==1&&Kp.size()==1&&pip.size()==1) {
	    double mplus  = (Kp [0].momentum()+pip[0].momentum()).mass2();
	    double mminus = (Kp [0].momentum()+pim[0].momentum()).mass2();
	    double mpipi  = (pip[0].momentum()+pim[0].momentum()).mass2();
	    _h_kppim5 ->fill(mminus);
	    _h_kppip5 ->fill(mplus );
	    _h_pippim5->fill(mpipi );
	    _dalitz5->fill(mminus,mpipi);
	  }
	}
	else if(abs(meson.pid())==431) {
	  if (pim.size()==1&&Kp.size()==1&&pip.size()==1) {
	    double mplus  = (Kp [0].momentum()+pip[0].momentum()).mass2();
	    double mminus = (Kp [0].momentum()+pim[0].momentum()).mass2();
	    double mpipi  = (pip[0].momentum()+pim[0].momentum()).mass2();
	    _h_kppim6 ->fill(mminus);
	    _h_kppip6 ->fill(mplus );
	    _h_pippim6->fill(mpipi );
	    _dalitz6->fill(mminus,mpipi);
	  }
	}
      }
    }

    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h_plus1);
      normalize(_h_minus1);
      normalize(_h_pipi1);
      normalize(_dalitz1);
      normalize(_h_minus2);
      normalize(_h_pipi2);
      normalize(_h_neutral2);
      normalize(_dalitz2);
      normalize(_h_Kpilow3);
      normalize(_h_Kpihigh3);
      normalize(_h_Kpiall3);
      normalize(_h_pipi3);
      normalize(_dalitz3);
      normalize(_h_Kpip4);
      normalize(_h_pipi4);
      normalize(_h_Kpi04);
      normalize(_dalitz4);
      normalize(_h_kppim5);
      normalize(_h_kppip5);
      normalize(_h_pippim5);
      normalize(_dalitz5);
      normalize(_h_kppim6);
      normalize(_h_kppip6);
      normalize(_h_pippim6);
      normalize(_dalitz6);
    }
    //@}

    /// @name Histograms
    //@{
    // Histograms for D^0\to \bar{K}^0\pi^+\pi^-
    //m^2_+
    Histo1DPtr _h_plus1;
    //m^2_+
    Histo1DPtr _h_minus1;
    //m^2_{\pi\pi}
    Histo1DPtr _h_pipi1;
    // Dalitz plot
    Histo2DPtr _dalitz1;
    
    // Histograms for D^0\to K^-\pi^+\pi^0
    // Histogram for the K^-\pi^+ mass
    Histo1DPtr _h_minus2;
    // Histogram for the \pi^+\pi^0 mass
    Histo1DPtr _h_pipi2;
    // Histogram for the K^-\pi^0 mass
    Histo1DPtr _h_neutral2;
    // Dalitz plot
    Histo2DPtr _dalitz2;

    // Histograms for D^+\to K^-\pi^+\pi^+
    // Histogram for K^-\pi^+ low
    Histo1DPtr _h_Kpilow3;
    // Histogram for K^-\pi^+ high
    Histo1DPtr _h_Kpihigh3;
    // Histogram for K^-\pi^+ all
    Histo1DPtr _h_Kpiall3;
    // Histogram for \pi^+\pi^-
    Histo1DPtr _h_pipi3;
    // Dalitz plot
    Histo2DPtr _dalitz3;

    // Histograms for D^+\to\bar{K}^0\pi^+\pi^0
    // Histogram for the \bar{K}^0\pi^+ mass
    Histo1DPtr _h_Kpip4;
    // Histogram for the \pi^+\pi^0 mass
    Histo1DPtr _h_pipi4;
    // Histogram for the \bar{K}^0\pi^0 mass
    Histo1DPtr _h_Kpi04;
    // Dalitz plot
    Histo2DPtr _dalitz4;

    // Histograms for D^+\to K^+\pi^-\pi^+
    // Histogram for K^+\pi^-
    Histo1DPtr _h_kppim5;
    // Histogram for K^+\pi^+
    Histo1DPtr _h_kppip5;
    // Histogram for \pi^+\pi^-
    Histo1DPtr _h_pippim5;
    // Dalitz plot
    Histo2DPtr _dalitz5;

    // Histograms for D_s^+\to K^+\pi^-\pi^+
    // Histogram for K^+\pi^-
    Histo1DPtr _h_kppim6;
    // Histogram for K^+\pi^+
    Histo1DPtr _h_kppip6;
    // Histogram for \pi^+\pi^-
    Histo1DPtr _h_pippim6;
    // Dalitz plot
    Histo2DPtr _dalitz6;
    //@}

  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(MC_D_Dalitz);


}