Rivet analyses referenceBABAR_2016_I1441203Dalitz plot analysis of $D^0\to \pi^+\pi^-\pi^0$Experiment: BABAR (PEP-II) Inspire ID: 1441203 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY
Measurement of the mass distributions in the decay $D^0\to \pi^+\pi^-\pi^0$. The data were read from the plots in the paper and the background subtracted. Resolution/acceptance effects have been unfolded and given the agreement with the model in the paper this analysis should only be used for qualitative studies. Source code: BABAR_2016_I1441203.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/DecayedParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief D0 -> pi+pi-pi0
10 class BABAR_2016_I1441203 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2016_I1441203);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // Initialise and register projections
23 UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
24 declare(ufs, "UFS");
25 DecayedParticles D0(ufs);
26 D0.addStable(PID::PI0);
27 D0.addStable(PID::K0S);
28 D0.addStable(PID::ETA);
29 D0.addStable(PID::ETAPRIME);
30 declare(D0, "D0");
31 // histograms
32 book(_h_pi[0],1,1,1);
33 book(_h_pi[1],1,1,2);
34 book(_h_pi[2],1,1,3);
35 book(_dalitz, "dalitz",50,0.,3.2,50,0.0,3.2);
36 }
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { 211,1},{-211,1}, {111,1}};
41 DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
42 // loop over particles
43 for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
44 if( ! D0.modeMatches(ix,3,mode) ) continue;
45 int sign = D0.decaying()[ix].pid()/421;
46 const Particles & pi0 = D0.decayProducts()[ix].at(111);
47 const Particles & pip = D0.decayProducts()[ix].at( sign*211);
48 const Particles & pim = D0.decayProducts()[ix].at(-sign*211);
49 double mneut = (pim[0].momentum()+pip[0].momentum()).mass2();
50 // if(mneut>475*MeV && mneut<505*MeV) continue;
51 double mplus = (pip[0].momentum()+pi0[0].momentum()).mass2();
52 double mminus = (pim[0].momentum()+pi0[0].momentum()).mass2();
53 _h_pi[0]->fill(mplus);
54 _h_pi[1]->fill(mminus);
55 _h_pi[2]->fill(mneut);
56 _dalitz->fill(mplus,mminus);
57 }
58 }
59
60
61 /// Normalise histograms etc., after the run
62 void finalize() {
63 for(unsigned int ix=0;ix<3;++ix)
64 normalize(_h_pi[ix]);
65 normalize(_dalitz);
66 }
67
68 /// @}
69
70
71 /// @name Histograms
72 /// @{
73 Histo1DPtr _h_pi[3];
74 Histo2DPtr _dalitz;
75 /// @}
76
77
78 };
79
80
81 RIVET_DECLARE_PLUGIN(BABAR_2016_I1441203);
82
83}
|
