Rivet analyses referenceBESIII_2022_I2084294Dalitz decay of $D^+_s\to K^+\pi^+\pi^-$Experiment: BESIII (BEPC) Inspire ID: 2084294 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $D^+_s\to K^+\pi^+\pi^-$ 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_2022_I2084294.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 Ds+ -> K+ pi+ pi-
10 class BESIII_2022_I2084294 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2084294);
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::ETA);
29 DS.addStable(PID::ETAPRIME);
30 declare(DS, "DS");
31 // histograms
32 book(_h_Kpip,1,1,1);
33 book(_h_Kpim,1,1,2);
34 book(_h_pipi,1,1,3);
35 book(_dalitz,"dalitz",50,0.,2.3,50,0.3,3.5);
36 }
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { 321,1}, { 211,1},{-211,1}};
41 static const map<PdgId,unsigned int> & modeCC = { {-321,1}, {-211,1},{ 211,1}};
42 DecayedParticles DS = apply<DecayedParticles>(event, "DS");
43 // loop over particles
44 for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
45 int sign = 1;
46 if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
47 sign=1;
48 }
49 else if (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
50 sign=-1;
51 }
52 else
53 continue;
54 const Particle & Kp = DS.decayProducts()[ix].at( sign*321)[0];
55 const Particle & pip= DS.decayProducts()[ix].at( sign*211)[0];
56 const Particle & pim= DS.decayProducts()[ix].at(-sign*211)[0];
57 double mp = (Kp .momentum()+pip.momentum()).mass2();
58 double mm = (Kp .momentum()+pim.momentum()).mass2();
59 double mpipi = (pip.momentum()+pim.momentum()).mass2();
60 _dalitz->fill(mpipi,mm);
61 if(mpipi<sqr(.4676) || mpipi>sqr(0.5276)) {
62 _h_pipi->fill(sqrt(mpipi));
63 _h_Kpip->fill(sqrt(mp));
64 _h_Kpim->fill(sqrt(mm));
65 }
66 }
67 }
68
69
70 /// Normalise histograms etc., after the run
71 void finalize() {
72 normalize(_h_Kpip);
73 normalize(_h_Kpim);
74 normalize(_h_pipi);
75 normalize(_dalitz);
76 }
77
78 /// @}
79
80
81 /// @name Histograms
82 /// @{
83 Histo1DPtr _h_Kpip,_h_Kpim,_h_pipi;
84 Histo2DPtr _dalitz;
85 /// @}
86
87
88 };
89
90
91 RIVET_DECLARE_PLUGIN(BESIII_2022_I2084294);
92
93}
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