Rivet analyses referenceBESIII_2019_I1724547Dalitz decay of $D_s^+\to\pi^+\pi^0\eta$Experiment: BESIII (BEPC) Inspire ID: 1724547 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $D^+_s\to \pi^+\pi^0\eta$ 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_2019_I1724547.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_2019_I1724547 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2019_I1724547);
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 declare(DS,"DS");
30 // histograms
31 book(_h_pipi, 1,1,1);
32 book(_h_etapip[0],1,1,2);
33 book(_h_etapip[1],1,1,4);
34 book(_h_etapi0[0],1,1,3);
35 book(_h_etapi0[1],1,1,5);
36 book(_dalitz, "dalitz",50,0.3,3.4,50,0.3,3.4);
37 }
38
39 /// Perform the per-event analysis
40 void analyze(const Event& event) {
41 static const map<PdgId,unsigned int> & mode = { { 211,1},{ 111,1}, {221,1}};
42 static const map<PdgId,unsigned int> & modeCC = { {-211,1},{ 111,1}, {221,1}};
43 DecayedParticles DS = apply<DecayedParticles>(event, "DS");
44 // loop over particles
45 for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
46 int sign = 1;
47 if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
48 sign=1;
49 }
50 else if (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
51 sign=-1;
52 }
53 else
54 continue;
55 const Particle & eta = DS.decayProducts()[ix].at( 221)[0];
56 const Particle & pi0 = DS.decayProducts()[ix].at( 111)[0];
57 const Particle & pip = DS.decayProducts()[ix].at( sign*211)[0];
58 double mplus = (eta.momentum()+pip.momentum()).mass2();
59 double mzero = (eta.momentum()+pi0.momentum()).mass2();
60 double mpipi = (pip.momentum()+pi0.momentum()).mass2();
61 _dalitz->fill(mplus,mzero);
62 _h_pipi ->fill(sqrt(mpipi));
63 _h_etapip[0]->fill(sqrt(mplus));
64 _h_etapi0[0]->fill(sqrt(mzero));
65 if(mpipi>1.) {
66 _h_etapip[1]->fill(sqrt(mplus));
67 _h_etapi0[1]->fill(sqrt(mzero));
68 }
69 }
70 }
71
72 /// Normalise histograms etc., after the run
73 void finalize() {
74 normalize(_h_pipi );
75 normalize(_h_etapip[0]);
76 normalize(_h_etapip[1]);
77 normalize(_h_etapi0[0]);
78 normalize(_h_etapi0[1]);
79 normalize(_dalitz );
80 }
81
82 /// @}
83 /// @name Histograms
84 /// @{
85 Histo1DPtr _h_pipi, _h_etapip[2],_h_etapi0[2];
86 Histo2DPtr _dalitz;
87 /// @}
88
89
90 };
91
92
93 RIVET_DECLARE_PLUGIN(BESIII_2019_I1724547);
94
95}
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