Rivet analyses referenceBESIII_2021_I1921801Mass distributions in $\psi(2S)\to\omega K^0_SK^0_S$Experiment: BESIII (BEPC) Inspire ID: 1921801 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of mass distributions in $\psi(2S)\to\omega K^0_SK^0_S$ by BES. N.B. data read from plots and may not be corrected, no difference between $K_{S1}^0$ and $K^0_{S2}$ so these are symeterised. Source code: BESIII_2021_I1921801.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 psi(2S) -> omega KS0 KS0
10 class BESIII_2021_I1921801 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1921801);
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::pid==100443);
24 declare(ufs, "UFS");
25 DecayedParticles psi2S(ufs);
26 psi2S.addStable(PID::PI0);
27 psi2S.addStable(PID::K0S);
28 psi2S.addStable(PID::ETA);
29 psi2S.addStable(PID::ETAPRIME);
30 psi2S.addStable(PID::OMEGA);
31 declare(psi2S, "psi2S");
32 // histograms
33 for(unsigned int ix=0;ix<3;++ix)
34 book(_h[ix],1,1,1+ix);
35 book(_dalitz, "dalitz" ,50,1.,11.,50,1.,11.);
36 }
37
38
39 /// Perform the per-event analysis
40 void analyze(const Event& event) {
41 // define the decay mode
42 static const map<PdgId,unsigned int> & mode = { { 310,2},{ 223,1}};
43 DecayedParticles psi2S = apply<DecayedParticles>(event, "psi2S");
44 // loop over particles
45 for(unsigned int ix=0;ix<psi2S.decaying().size();++ix) {
46 if(!psi2S.modeMatches(ix,3,mode)) continue;
47 const Particles & K0 = psi2S.decayProducts()[ix].at(310);
48 const Particles & omega = psi2S.decayProducts()[ix].at(223);
49 double m2Komega[2]={(K0[0].momentum()+omega[0].momentum()).mass2(),
50 (K0[1].momentum()+omega[0].momentum()).mass2()};
51 for(unsigned int ix=0;ix<2;++ix) {
52 double mKo = sqrt(m2Komega[ix]);
53 _h[0]->fill(mKo);
54 _h[1]->fill(mKo);
55 }
56 _h[2]->fill((K0[0].momentum()+K0[1].momentum()).mass());
57 _dalitz->fill(m2Komega[0],m2Komega[1]);
58 _dalitz->fill(m2Komega[1],m2Komega[0]);
59 }
60 }
61
62
63 /// Normalise histograms etc., after the run
64 void finalize() {
65 for(unsigned int ix=0;ix<3;++ix)
66 normalize(_h[ix],1.,false);
67 normalize(_dalitz);
68 }
69
70 /// @}
71
72
73 /// @name Histograms
74 /// @{
75 Histo1DPtr _h[3];
76 Histo2DPtr _dalitz;
77 /// @}
78
79
80 };
81
82
83 RIVET_DECLARE_PLUGIN(BESIII_2021_I1921801);
84
85}
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