Rivet analyses referenceBESIII_2022_I2030993Dalitz decay of D+s→π+π0η′Experiment: BESIII (BEPC) Inspire ID: 2030993 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay D+s→π+π0η′ by BES. The data were read from the plots in the paper. It is also not clear that any resolution effects have been unfolded. Source code: BESIII_2022_I2030993.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+ -> pi+ pi0 eta'
10 class BESIII_2022_I2030993 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2030993);
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 DS.addStable(PID::ETAPRIME);
29 declare(DS,"DS");
30 // histograms
31 book(_h_etapip,1,1,1);
32 book(_h_etapi0,1,1,2);
33 book(_h_pipi , 1,1,3);
34 book(_dalitz, "dalitz",50,0.,1.1,50,1,3.5);
35 }
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 static const map<PdgId,unsigned int> & mode = { { 211,1}, { 111,1}, { 331,1}};
40 static const map<PdgId,unsigned int> & modeCC = { {-211,1}, { 111,1}, { 331,1}};
41 DecayedParticles DS = apply<DecayedParticles>(event, "DS");
42 // loop over particles
43 for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
44 int sign = 1;
45 if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
46 sign=1;
47 }
48 else if (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
49 sign=-1;
50 }
51 else
52 continue;
53 const Particle & pip = DS.decayProducts()[ix].at( sign*211)[0];
54 const Particle & pi0 = DS.decayProducts()[ix].at( 111)[0];
55 const Particle & eta = DS.decayProducts()[ix].at( 331)[0];
56 double mplus = (eta.momentum()+pip.momentum()).mass2();
57 double mzero = (eta.momentum()+pi0.momentum()).mass2();
58 double mpipi = (pip.momentum()+pi0.momentum()).mass2();
59 _dalitz ->fill(mpipi,mplus);
60 _h_pipi ->fill(sqrt(mpipi));
61 _h_etapip->fill(sqrt(mplus));
62 _h_etapi0->fill(sqrt(mzero));
63 }
64 }
65
66
67 /// Normalise histograms etc., after the run
68 void finalize() {
69 normalize(_h_pipi ,1.,false);
70 normalize(_h_etapip,1.,false);
71 normalize(_h_etapi0,1.,false);
72 normalize(_dalitz ,1.,false);
73 }
74
75 /// @}
76
77
78 /// @name Histograms
79 /// @{
80 Histo1DPtr _h_pipi, _h_etapip,_h_etapi0;
81 Histo2DPtr _dalitz;
82 /// @}
83
84
85 };
86
87
88 RIVET_DECLARE_PLUGIN(BESIII_2022_I2030993);
89
90}
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