Rivet analyses referenceBESIII_2013_I1203840$\psi(2S)\to \bar{p}K^+\Sigma^0$ and $\chi_{cJ}\to\bar{p}K^+\Lambda^0$Experiment: BESIII (BEPC) Inspire ID: 1203840 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurements of mass distributions in the decays $\psi(2S)\to \bar{p}K^+\Sigma^0$ and $\chi_{cJ}\to\bar{p}K^+\Lambda^0$. The data were read from the plots in the paper and may not be corrected for efficiency or background. Source code: BESIII_2013_I1203840.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) -> pbar K+ Sigma^$ and chi_cJ -> pbar K+Lambda
10 class BESIII_2013_I1203840 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2013_I1203840);
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 or
25 Cuts::pid==100443);
26 declare(ufs, "UFS");
27 DecayedParticles chi(ufs);
28 chi.addStable( PID::PI0);
29 chi.addStable( PID::K0S);
30 chi.addStable( PID::SIGMA0);
31 chi.addStable( PID::SIGMA0);
32 chi.addStable( PID::LAMBDA);
33 chi.addStable(-PID::LAMBDA);
34 declare(chi, "chi");
35 // histograms
36 for(unsigned int ix=0;ix<2;++ix) {
37 book(_h_psi[ix],1,1,ix+1);
38 for(unsigned int iy=0;iy<3;++iy)
39 book(_h_chi[iy][ix],2,iy+1,ix+1);
40 }
41 book(_h_pLam,3,1,1);
42 }
43
44
45 /// Perform the per-event analysis
46 void analyze(const Event& event) {
47 static const map<PdgId,unsigned int> & mode1 = { {-2212,1}, { 3212,1}, { 321,1} };
48 static const map<PdgId,unsigned int> & mode1CC = { { 2212,1}, {-3212,1}, {-321,1} };
49 static const map<PdgId,unsigned int> & mode2 = { {-2212,1}, { 3122,1}, { 321,1} };
50 static const map<PdgId,unsigned int> & mode2CC = { { 2212,1}, {-3122,1}, {-321,1} };
51 DecayedParticles chi = apply<DecayedParticles>(event, "chi");
52 // loop over particles
53 for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
54 int sign=1;
55 if(chi.decaying()[ix].pid()==100443) {
56 if(chi.modeMatches(ix,3,mode1)) {
57 sign = 1;
58 }
59 else if(chi.modeMatches(ix,3,mode1CC)) {
60 sign = -1;
61 }
62 else continue;
63 const Particle & pbar = chi.decayProducts()[ix].at(-sign*2212)[0];
64 const Particle & Kp = chi.decayProducts()[ix].at( sign*321 )[0];
65 const Particle & sigma = chi.decayProducts()[ix].at( sign*3212)[0];
66 _h_psi[0]->fill((pbar.momentum()+sigma.momentum()).mass());
67 _h_psi[1]->fill((Kp .momentum()+sigma.momentum()).mass());
68 }
69 else {
70 if(chi.modeMatches(ix,3,mode2)) {
71 sign = 1;
72 }
73 else if(chi.modeMatches(ix,3,mode2CC)) {
74 sign = -1;
75 }
76 else continue;
77 unsigned int iloc = chi.decaying()[ix].pid()==10441 ? 0 : chi.decaying()[ix].pid()==445 ? 2 : 1;
78 const Particle & pbar = chi.decayProducts()[ix].at(-sign*2212)[0];
79 const Particle & Kp = chi.decayProducts()[ix].at( sign*321 )[0];
80 const Particle & lam = chi.decayProducts()[ix].at( sign*3122)[0];
81 _h_chi[iloc][0]->fill((pbar.momentum()+Kp .momentum()).mass());
82 _h_chi[iloc][1]->fill((Kp .momentum()+lam.momentum()).mass());
83 if(iloc==0) _h_pLam->fill((pbar.momentum()+lam.momentum()).mass());
84 }
85 }
86 }
87
88
89 /// Normalise histograms etc., after the run
90 void finalize() {
91 for(unsigned int ix=0;ix<2;++ix) {
92 normalize(_h_psi[ix],1.,false);
93 for(unsigned int iy=0;iy<3;++iy)
94 normalize(_h_chi[iy][ix],1.,false);
95 }
96 normalize(_h_pLam,1.,false);
97 }
98
99 /// @}
100
101
102 /// @name Histograms
103 /// @{
104 Histo1DPtr _h_psi[2],_h_chi[3][2],_h_pLam;
105 /// @}
106
107
108 };
109
110
111 RIVET_DECLARE_PLUGIN(BESIII_2013_I1203840);
112
113}
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