Rivet analyses referenceBESIII_2017_I1505590$\chi_{c2}$ decays to $K^+K^-\pi^0$, $K^0_SK^\pm\pi^\mp$ and $\pi^+\pi^-\pi^0$Experiment: BESIII (BEPC) Inspire ID: 1505590 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Mass distributions in $\chi_{c2}$ decays to $K^+K^-\pi^0$, $K^0_SK^\pm\pi^\mp$ and $\pi^+\pi^-\pi^0$. The data was read from the plots in the paper and is not corrected for efficiency and acceptance. Source code: BESIII_2017_I1505590.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 chi_c2 decays
10 class BESIII_2017_I1505590 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2017_I1505590);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // projections
23 UnstableParticles ufs = UnstableParticles(Cuts::pid==445);
24 declare(ufs, "UFS");
25 DecayedParticles chi(ufs);
26 chi.addStable( PID::PI0);
27 chi.addStable( PID::K0S);
28 declare(chi, "chi");
29 // histograms
30 for(unsigned int ix=0; ix<4; ++ix) {
31 if (ix<2) book(_h[ix], 1, 1, 1+ix);
32 book(_h[2+ix], 2, 1, 1+ix);
33 }
34 }
35
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 DecayedParticles chi = apply<DecayedParticles>(event, "chi");
40 // loop over particles
41 for (unsigned int ix=0; ix<chi.decaying().size(); ++ix) {
42 int sign=1;
43 // K+ K- pi0
44 if (chi.modeMatches(ix,3,mode1)) {
45 const Particle& Kp = chi.decayProducts()[ix].at( 321)[0];
46 const Particle& Km = chi.decayProducts()[ix].at(-321)[0];
47 const Particle& pi0 = chi.decayProducts()[ix].at( 111)[0];
48 _h[0]->fill((Kp.mom()+pi0.mom()).mass()/GeV);
49 _h[0]->fill((Km.mom()+pi0.mom()).mass()/GeV);
50 _h[1]->fill((Kp.mom()+Km .mom()).mass()/GeV);
51 continue;
52 }
53 // pi+ pi- pi0
54 else if (chi.modeMatches(ix,3,mode3)) {
55 const Particle & pip = chi.decayProducts()[ix].at( 211)[0];
56 const Particle & pim = chi.decayProducts()[ix].at(-211)[0];
57 const Particle & pi0 = chi.decayProducts()[ix].at( 111)[0];
58 _h[5]->fill((pip.mom()+pi0.mom()).mass()/GeV);
59 _h[5]->fill((pim.mom()+pi0.mom()).mass()/GeV);
60 continue;
61 }
62 else if (chi.modeMatches(ix,3,mode2)) {
63 sign = 1;
64 }
65 else if (chi.modeMatches(ix,3,mode2CC)) {
66 sign = -1;
67 }
68 else {
69 continue;
70 }
71 const Particle& KS0 = chi.decayProducts()[ix].at( 310)[0];
72 const Particle& Kp = chi.decayProducts()[ix].at( sign*321)[0];
73 const Particle & pim = chi.decayProducts()[ix].at(-sign*211)[0];
74 _h[2]->fill((Kp .mom()+pim.mom()).mass()/GeV);
75 _h[3]->fill((KS0.mom()+pim.mom()).mass()/GeV);
76 _h[4]->fill((KS0.mom()+Kp .mom()).mass()/GeV);
77 }
78 }
79
80
81 /// Normalise histograms etc., after the run
82 void finalize() {
83 normalize(_h, 1.0, false);
84 }
85
86 /// @}
87
88
89 /// @name Histograms
90 /// @{
91 Histo1DPtr _h[6];
92 const map<PdgId,unsigned int> mode1 = { { 321,1}, {-321,1}, { 111,1} };
93 const map<PdgId,unsigned int> mode2 = { { 310,1}, { 321,1}, {-211,1} };
94 const map<PdgId,unsigned int> mode2CC = { { 310,1}, {-321,1}, { 211,1} };
95 const map<PdgId,unsigned int> mode3 = { { 211,1}, {-211,1}, { 111,1} };
96 /// @}
97
98
99 };
100
101
102 RIVET_DECLARE_PLUGIN(BESIII_2017_I1505590);
103
104}
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