Rivet analyses
title: MARKIII_1987_I247266
Dalitz plot analysis of $D\to K\pi\pi$ 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 $D^0\to K^-\pi^+\pi^0$, $D^0\to K^0_S\pi^+\pi^-$, $D^+\to K^0_S\pi^+\pi^0$ and $D^+\to K^-\pi^+\pi^+$. 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++ // -- 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);
} ```