Rivet analyses referenceBESIII_2021_I1854317Dalitz decay of $D^+_s\to K^0_S\pi^+\pi^0$Experiment: BESIII () Inspire ID: 1854317 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $D^+_s\to K^0_S\pi^+\pi^0$ by BES. The data were read from the plots in the paper and therefore for some points the error bars are the size of the point. It is also not clear that any resolution effects have been unfolded. Source code: BESIII_2021_I1854317.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_s+ -> KS0 pi+ pi0
10 class BESIII_2021_I1854317 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1854317);
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==431);
24 declare(ufs, "UFS");
25 DecayedParticles DS(ufs);
26 DS.addStable(PID::PI0);
27 DS.addStable(PID::K0S);
28 declare(DS, "DS");
29 // histograms
30 book(_h_Kpi0,1,1,1);
31 book(_h_Kpip,1,1,2);
32 book(_h_pipi,1,1,3);
33 book(_dalitz,"dalitz",50,0.3,3.5,50,0.3,3.5);
34 }
35
36 /// Perform the per-event analysis
37 void analyze(const Event& event) {
38 static const map<PdgId,unsigned int> & mode = { { 211,1},{ 111,1}, {310,1}};
39 static const map<PdgId,unsigned int> & modeCC = { {-211,1},{ 111,1}, {310,1}};
40 DecayedParticles DS = apply<DecayedParticles>(event, "DS");
41 // loop over particles
42 for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
43 int sign = 1;
44 if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
45 sign=1;
46 }
47 else if (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
48 sign=-1;
49 }
50 else
51 continue;
52 const Particle & K0 = DS.decayProducts()[ix].at( 310)[0];
53 const Particle & pi0 = DS.decayProducts()[ix].at( 111)[0];
54 const Particle & pip = DS.decayProducts()[ix].at( sign*211)[0];
55 double mplus = (K0 .momentum()+pip.momentum()).mass2();
56 double mzero = (K0 .momentum()+pi0.momentum()).mass2();
57 double mpipi = (pip.momentum()+pi0.momentum()).mass2();
58 _dalitz->fill(mzero,mplus);
59 _h_pipi->fill(sqrt(mpipi));
60 _h_Kpip->fill(sqrt(mplus));
61 _h_Kpi0->fill(sqrt(mzero));
62 }
63 }
64
65
66 /// Normalise histograms etc., after the run
67 void finalize() {
68 normalize(_h_Kpi0);
69 normalize(_h_Kpip);
70 normalize(_h_pipi);
71 normalize(_dalitz);
72 }
73
74 /// @}
75
76
77 /// @name Histograms
78 /// @{
79 Histo1DPtr _h_Kpi0,_h_Kpip,_h_pipi;
80 Histo2DPtr _dalitz;
81 /// @}
82
83
84 };
85
86
87 RIVET_DECLARE_PLUGIN(BESIII_2021_I1854317);
88
89}
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