Rivet analyses referenceBABAR_2010_I853279Dalitz plot analysis of $D^0\to K^0_S\pi^+\pi^-$ and $D^0\to K^0_SK^+K^-$Experiment: BABAR (PEP-II) Inspire ID: 853279 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of Kinematic distributions in the decays $D^0\to K^0_S\pi^+\pi^-$ and $D^0\to K^0_SK^+K^-$ by BaBar. The data were read from the plots in the paper. Resolution/acceptance effects have been not unfolded. Given the agreement with the model in the paper this analysis should only be used for qualitative studies. Source code: BABAR_2010_I853279.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 -> KS0 pi+pi- and K+K-
10 class BABAR_2010_I853279 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2010_I853279);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22
23 // Initialise and register projections
24 UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
25 declare(ufs, "UFS");
26 DecayedParticles D0(ufs);
27 D0.addStable(PID::PI0);
28 D0.addStable(PID::K0S);
29 D0.addStable(PID::ETA);
30 D0.addStable(PID::ETAPRIME);
31 declare(D0, "D0");
32 // Histograms
33 book(_h_Kpim,1,1,1);
34 book(_h_Kpip,1,1,2);
35 book(_h_pipi,1,1,3);
36 book(_dalitz[0], "dalitz1",50,0.3,3.2,50,0.3,3.2);
37 book(_h_K0Km,1,1,4);
38 book(_h_K0Kp,1,1,5);
39 book(_h_KpKm,1,1,6);
40 book(_dalitz[1], "dalitz2",50,0.9,1.9,50,0.9,1.9);
41 }
42
43 /// Perform the per-event analysis
44 void analyze(const Event& event) {
45 // define the decay mode
46 static const map<PdgId,unsigned int> & modePi = { { 310,1}, { 211,1},{-211,1}};
47 static const map<PdgId,unsigned int> & modeK = { { 310,1}, { 321,1},{-321,1}};
48 DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
49 // loop over particles
50 for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
51 int sign = D0.decaying()[ix].pid()/421;
52 // KS0 pi+pi-
53 if (D0.modeMatches(ix,3,modePi) ) {
54 const Particles & pip= D0.decayProducts()[ix].at( sign*211);
55 const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
56 const Particles & K0 = D0.decayProducts()[ix].at( 310);
57 double mminus = (pim[0].momentum()+K0[0].momentum() ).mass2();
58 double mplus = (pip[0].momentum()+K0[0].momentum() ).mass2();
59 double mpipi = (pip[0].momentum()+pim[0].momentum()).mass2();
60 _h_Kpip->fill(mplus);
61 _h_Kpim->fill(mminus);
62 _h_pipi->fill(mpipi);
63 _dalitz[0]->fill(mminus,mplus);
64 }
65 else if (D0.modeMatches(ix,3,modeK) ) {
66 const Particles & Kp = D0.decayProducts()[ix].at( sign*321);
67 const Particles & Km = D0.decayProducts()[ix].at(-sign*321);
68 const Particles & K0 = D0.decayProducts()[ix].at( 310);
69 double mminus = (Km[0].momentum()+K0[0].momentum() ).mass2();
70 double mplus = (Kp[0].momentum()+K0[0].momentum() ).mass2();
71 double mKK = (Kp[0].momentum()+Km[0].momentum()).mass2();
72 _h_K0Kp->fill(mplus);
73 _h_K0Km->fill(mminus);
74 _h_KpKm->fill(mKK);
75 }
76 }
77 }
78
79
80 /// Normalise histograms etc., after the run
81 void finalize() {
82 normalize(_h_Kpim);
83 normalize(_h_Kpip);
84 normalize(_h_pipi);
85 normalize(_dalitz[0]);
86 normalize(_h_K0Km);
87 normalize(_h_K0Kp);
88 normalize(_h_KpKm);
89 normalize(_dalitz[1]);
90 }
91
92 /// @}
93
94
95 /// @name Histograms
96 /// @{
97 Histo1DPtr _h_Kpim,_h_pipi,_h_Kpip;
98 Histo1DPtr _h_K0Km,_h_KpKm,_h_K0Kp;
99 Histo2DPtr _dalitz[2];
100 /// @}
101
102
103 };
104
105
106 RIVET_DECLARE_PLUGIN(BABAR_2010_I853279);
107
108}
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