Rivet analyses
Dalitz plot analysis of D → Kππ decays
Experiment: MARKIII (PEP)
Inspire ID: 247266
Status: VALIDATED NOHEPDATA
Authors: - Peter Richardson
References: - Phys.Lett.B 196 (1987) 107-112
Beams: * *
Beam energies: ANY
Run details: - Any process producing D0 and D+ mesons
Measurement of the mass distributions in the decays D0 → K−π+π0, D0 → KS0π+π−, D+ → KS0π+π0 and D+ → K−π+π+. The data were read from the plots in the paper. Resolution/acceptance effects have been not unfolded and given the agreement with the model in the paper this analysis should only be used for qualitative studies.
Source
code:MARKIII_1987_I247266.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief D -> K pi pi dalitz decays
class MARKIII_1987_I247266 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MARKIII_1987_I247266);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==411 or
Cuts::abspid==421);
declare(ufs, "UFS");
DecayedParticles DD(ufs);
DD.addStable(PID::PI0);
DD.addStable(PID::K0S);
declare(DD, "DD");
// histos
book(_h_1_Kmpip,1,1,1);
book(_h_1_pipi ,1,1,2);
book(_h_1_Kmpi0,1,1,3);
book(_dalitz1, "dalitz1",50,0.3,3.2,50,0.,2.);
book(_h_2_K0pip,2,1,1);
book(_h_2_pipi ,2,1,2);
book(_h_2_K0pim,2,1,3);
book(_dalitz2, "dalitz2",50,0.3,3.2,50,0.,2.);
book(_h_3_K0pip,3,1,1);
book(_h_3_pipi ,3,1,2);
book(_h_3_K0pi0,3,1,3);
book(_dalitz3, "dalitz3",50,0.3,3.2,50,0.,2.);
book(_h_4_Kmpip[0],4,1,1);
book(_h_4_pipi ,4,1,2);
book(_h_4_Kmpip[1],4,1,3);
book(_dalitz4, "dalitz4",50,0.3,2.,50,0.,2.);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { { 211,1}, {-321,1}, {111,1} };
static const map<PdgId,unsigned int> & mode1CC = { {-211,1}, { 321,1}, {111,1} };
static const map<PdgId,unsigned int> & mode2 = { { 211,1}, {-211,1}, {310,1} };
static const map<PdgId,unsigned int> & mode3 = { { 211,1}, { 111,1}, {310,1} };
static const map<PdgId,unsigned int> & mode3CC = { {-211,1}, { 111,1}, {310,1} };
static const map<PdgId,unsigned int> & mode4 = { { 211,2}, {-321,1} };
static const map<PdgId,unsigned int> & mode4CC = { {-211,2}, { 321,1} };
DecayedParticles DD = apply<DecayedParticles>(event, "DD");
for(unsigned int ix=0;ix<DD.decaying().size();++ix) {
int sign = DD.decaying()[ix].pid()/DD.decaying()[ix].abspid();
if(DD.decaying()[ix].abspid()==421) {
if ( ( DD.decaying()[ix].pid()>0 && DD.modeMatches(ix,3,mode1 )) ||
( DD.decaying()[ix].pid()<0 && DD.modeMatches(ix,3,mode1CC))) {
const Particle & pi0 = DD.decayProducts()[ix].at( 111)[0];
const Particle & pip = DD.decayProducts()[ix].at( sign*211)[0];
const Particle & Km = DD.decayProducts()[ix].at(-sign*321)[0];
double mneut = (Km.momentum()+pip.momentum()).mass2();
double mminus = (Km.momentum()+pi0.momentum()).mass2();
double mpipi = (pip.momentum()+pi0.momentum()).mass2();
_h_1_Kmpip->fill(mneut );
_h_1_pipi ->fill(mpipi );
_h_1_Kmpi0->fill(mminus);
_dalitz1 ->fill(mminus,mpipi);
}
else if ( DD.modeMatches(ix,3,mode2 )) {
const Particle & K0 = DD.decayProducts()[ix].at( 310)[0];
const Particle & pip = DD.decayProducts()[ix].at( sign*211)[0];
const Particle & pim = DD.decayProducts()[ix].at(-sign*211)[0];
double mminus = (pim.momentum()+K0.momentum() ).mass2();
double mplus = (pip.momentum()+K0.momentum() ).mass2();
double mpipi = (pip.momentum()+pim.momentum()).mass2();
_h_2_K0pip->fill(mplus);
_h_2_K0pim->fill(mminus);
_h_2_pipi ->fill(mpipi);
_dalitz2 ->fill(mminus,mpipi);
}
}
else if(DD.decaying()[ix].abspid()==411) {
if(DD.modeMatches(ix,3,mode3 ) || DD.modeMatches(ix,3,mode3CC)) {
const Particle & pi0 = DD.decayProducts()[ix].at( 111)[0];
const Particle & K0 = DD.decayProducts()[ix].at( 310)[0];
const Particle & pip = DD.decayProducts()[ix].at( sign*211)[0];
double mminus = (K0.momentum()+pip.momentum()).mass2();
double mplus = (K0.momentum()+pi0.momentum()).mass2();
double mpipi = (pip.momentum()+pi0.momentum()).mass2();
_h_3_K0pip->fill( mminus);
_h_3_pipi ->fill( mpipi );
_h_3_K0pi0->fill( mplus );
_dalitz3 ->fill(mplus,mpipi);
}
else if(DD.modeMatches(ix,3,mode4 ) || DD.modeMatches(ix,3,mode4CC)) {
const Particles & pip = DD.decayProducts()[ix].at( sign*211);
const Particle & Km = DD.decayProducts()[ix].at(-sign*321)[0];
double mplus = (Km.momentum() +pip[0].momentum()).mass2();
double mminus = (Km.momentum() +pip[1].momentum()).mass2();
double mpipi = (pip[0].momentum()+pip[1].momentum()).mass2();
if(mplus<mminus) swap(mplus,mminus);
_h_4_Kmpip[1]->fill(mminus);
_h_4_Kmpip[0]->fill(mplus );
_h_4_pipi ->fill( mpipi);
_dalitz4 ->fill(mminus,mpipi);
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_1_Kmpip);
normalize(_h_1_pipi );
normalize(_h_1_Kmpi0);
normalize(_dalitz1 );
normalize(_h_2_K0pip);
normalize(_h_2_pipi );
normalize(_h_2_K0pim);
normalize(_dalitz2 );
normalize(_h_3_K0pip);
normalize(_h_3_pipi );
normalize(_h_3_K0pi0);
normalize(_dalitz3 );
normalize(_h_4_Kmpip[0]);
normalize(_h_4_pipi );
normalize(_h_4_Kmpip[1]);
normalize(_dalitz4 );
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_1_Kmpip, _h_1_pipi, _h_1_Kmpi0;
Histo2DPtr _dalitz1;
Histo1DPtr _h_2_K0pip, _h_2_pipi, _h_2_K0pim;
Histo2DPtr _dalitz2;
Histo1DPtr _h_3_K0pip, _h_3_pipi, _h_3_K0pi0;
Histo2DPtr _dalitz3;
Histo1DPtr _h_4_Kmpip[2], _h_4_pipi;
Histo2DPtr _dalitz4;
/// @}
};
RIVET_DECLARE_PLUGIN(MARKIII_1987_I247266);
}