Rivet analyses referenceBESIII_2021_I1859124Dalitz plot analysis of D+→K+K0Sπ0Experiment: BESIII (BEPC) Inspire ID: 1859124 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay D+→K+K0Sπ0. 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: BESIII_2021_I1859124.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 D+ -> K+ KS0 pi0
10 class BESIII_2021_I1859124 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1859124);
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==411);
24 declare(ufs, "UFS");
25 DecayedParticles DP(ufs);
26 DP.addStable(PID::PI0);
27 DP.addStable(PID::K0S);
28 declare(DP,"DP");
29 // histos
30 book(_h_Kppi0,1,1,1);
31 book(_h_K0pi0,1,1,2);
32 book(_h_KpK0,1,1,3);
33 book(_dalitz, "dalitz",50,0.3,2.,50,0.3,2.);
34 }
35
36 /// Perform the per-event analysis
37 void analyze(const Event& event) {
38 static const map<PdgId,unsigned int> & mode = { { 321,1},{ 111,1}, {310,1}};
39 static const map<PdgId,unsigned int> & modeCC = { {-321,1},{ 111,1}, {310,1}};
40 DecayedParticles DP = apply<DecayedParticles>(event, "DP");
41 // loop over particles
42 for(unsigned int ix=0;ix<DP.decaying().size();++ix) {
43 int sign = 1;
44 if (DP.decaying()[ix].pid()>0 && DP.modeMatches(ix,3,mode)) {
45 sign=1;
46 }
47 else if (DP.decaying()[ix].pid()<0 && DP.modeMatches(ix,3,modeCC)) {
48 sign=-1;
49 }
50 else
51 continue;
52 const Particle & K0 = DP.decayProducts()[ix].at( 310)[0];
53 const Particle & pi0 = DP.decayProducts()[ix].at( 111)[0];
54 const Particle & Kp = DP.decayProducts()[ix].at( sign*321)[0];
55 double mplus = (Kp.momentum() +pi0.momentum()).mass2();
56 double mneut = (K0.momentum() +pi0.momentum()).mass2();
57 double mKK = (Kp.momentum() + K0.momentum()).mass2();
58 _h_Kppi0->fill(sqrt(mplus));
59 _h_K0pi0->fill(sqrt(mneut));
60 _h_KpK0 ->fill(sqrt(mKK ));
61 _dalitz ->fill(mplus,mneut);
62 }
63 }
64
65
66 /// Normalise histograms etc., after the run
67 void finalize() {
68 normalize(_h_Kppi0);
69 normalize(_h_K0pi0);
70 normalize(_h_KpK0 );
71 normalize(_dalitz );
72 }
73
74 /// @}
75
76
77 /// @name Histograms
78 /// @{
79 Histo1DPtr _h_Kppi0,_h_K0pi0,_h_KpK0;
80 Histo2DPtr _dalitz;
81 /// @}
82
83
84 };
85
86
87 RIVET_DECLARE_PLUGIN(BESIII_2021_I1859124);
88
89}
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