Rivet analyses referenceBESIII_2020_I1818254$\chi_{c(0,1,2)}\to \Sigma^0 \bar{p} K^+$ + c.cExperiment: BESIII (BEPC) Inspire ID: 1818254 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decays $\chi_{c(0,1,2)}\to \Sigma^0 \bar{p} K^+$ + c.c. The data were read from the plots in the paper and may not be corrected for efficiency or background. Source code: BESIII_2020_I1818254.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_c -> pbar Sigma0 K+
10 class BESIII_2020_I1818254 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2020_I1818254);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 UnstableParticles ufs = UnstableParticles(Cuts::pid==20443 or
23 Cuts::pid==445 or
24 Cuts::pid==10441);
25 declare(ufs, "UFS");
26 DecayedParticles chi(ufs);
27 chi.addStable( PID::PI0);
28 chi.addStable( PID::K0S);
29 chi.addStable( PID::ETA);
30 chi.addStable( PID::ETAPRIME);
31 chi.addStable( PID::SIGMA0);
32 chi.addStable(-PID::SIGMA0);
33 declare(chi, "chi");
34 for(unsigned int ix=0;ix<3;++ix) {
35 book(_dalitz[ix], "dalitz_"+toString(ix+1),50,2.5,7.,50,1.8,6.);
36 for(unsigned int iy=0;iy<3;++iy) {
37 book(_h[ix][iy],1+ix,1,1+iy);
38 }
39 }
40 }
41
42
43 /// Perform the per-event analysis
44 void analyze(const Event& event) {
45 static const map<PdgId,unsigned int> & mode = { {-2212,1}, { 3212,1}, { 321,1} };
46 static const map<PdgId,unsigned int> & modeCC = { { 2212,1}, {-3212,1}, {-321,1} };
47 DecayedParticles chi = apply<DecayedParticles>(event, "chi");
48 // loop over particles
49 for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
50 int sign=1;
51 if(chi.modeMatches(ix,3,mode)) {
52 sign = 1;
53 }
54 else if(chi.modeMatches(ix,3,modeCC)) {
55 sign = -1;
56 }
57 else continue;
58 unsigned int iloc = chi.decaying()[ix].pid()==10441 ? 0 : chi.decaying()[ix].pid()==445 ? 2 : 1;
59 const Particle & Kp = chi.decayProducts()[ix].at( sign*321)[0];
60 const Particle & pbar = chi.decayProducts()[ix].at(-sign*2212)[0];
61 const Particle & sig = chi.decayProducts()[ix].at(sign*3212)[0];
62 double mpK = (Kp .momentum()+pbar.momentum()).mass2();
63 double msigK = (Kp .momentum()+sig .momentum()).mass2();
64 double msigp = (sig.momentum()+pbar.momentum()).mass2();
65 _h[iloc][0]->fill(sqrt(mpK));
66 _h[iloc][1]->fill(sqrt(msigK));
67 _h[iloc][2]->fill(sqrt(msigp));
68 _dalitz[iloc]->fill(msigK,mpK);
69 }
70 }
71
72
73 /// Normalise histograms etc., after the run
74 void finalize() {
75 for(unsigned int ix=0;ix<3;++ix) {
76 normalize(_dalitz[ix]);
77 for(unsigned int iy=0;iy<3;++iy) {
78 normalize(_h[ix][iy]);
79 }
80 }
81 }
82
83 /// @}
84
85
86 /// @name Histograms
87 /// @{
88 Histo1DPtr _h[3][3];
89 Histo2DPtr _dalitz[3];
90 /// @}
91
92
93 };
94
95
96 RIVET_DECLARE_PLUGIN(BESIII_2020_I1818254);
97
98}
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