Rivet analyses referenceBESII_2005_I690784$\chi_{c0}\to \pi^+\pi^- K^+K^-$Experiment: BESII (BEPC) Inspire ID: 690784 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decays $\chi_{c0}\to \pi^+\pi^- K^+K^-$. The data were read from the plots in the paper and may not be corrected for backgrounds and efficiency. Source code: BESII_2005_I690784.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_c0 -> pi+ pi- K+ K-
10 class BESII_2005_I690784 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2005_I690784);
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==10441);
23 declare(ufs, "UFS");
24 DecayedParticles chi(ufs);
25 chi.addStable( PID::PI0);
26 chi.addStable( PID::K0S);
27 chi.addStable( PID::ETA);
28 declare(chi, "chi");
29 for(unsigned int ix=0;ix<4;++ix)
30 book(_h[ix],1,1,ix+1);
31 }
32
33
34 /// Perform the per-event analysis
35 void analyze(const Event& event) {
36 static const map<PdgId,unsigned int> & mode1 = { { 211,1}, {-211,1}, {321,1}, {-321,1} };
37 DecayedParticles chi = apply<DecayedParticles>(event, "chi");
38 // loop over particles
39 for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
40 if(!chi.modeMatches(ix,4,mode1)) continue;
41 const Particle & pim = chi.decayProducts()[ix].at(-211)[0];
42 const Particle & pip = chi.decayProducts()[ix].at( 211)[0];
43 const Particle & Km = chi.decayProducts()[ix].at(-321)[0];
44 const Particle & Kp = chi.decayProducts()[ix].at( 321)[0];
45 _h[0]->fill((Km .momentum() +Kp.momentum()).mass());
46 _h[1]->fill((pim.momentum()+pip.momentum()).mass());
47 _h[2]->fill((Km .momentum()+pip.momentum()).mass());
48 _h[2]->fill((Kp .momentum()+pim.momentum()).mass());
49 _h[3]->fill((Km .momentum()+pip.momentum()+pim.momentum()).mass());
50 _h[3]->fill((Kp .momentum()+pim.momentum()+pip.momentum()).mass());
51 }
52 }
53
54
55 /// Normalise histograms etc., after the run
56 void finalize() {
57 for(unsigned int ix=0;ix<4;++ix)
58 normalize(_h[ix]);
59 }
60
61 /// @}
62
63
64 /// @name Histograms
65 /// @{
66 Histo1DPtr _h[4];
67 /// @}
68
69
70 };
71
72
73 RIVET_DECLARE_PLUGIN(BESII_2005_I690784);
74
75}
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