Rivet analyses referenceBESIII_2013_I1261765$\psi(2S)\to \Lambda^0\bar\Sigma^\pm\pi^\mp$ + c.c.Experiment: BESIII (BEPC) Inspire ID: 1261765 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurements of mass distributions in the decays $\psi(2S)\to \Lambda^0\bar\Sigma^\pm\pi^\mp$ +c.c.. The data were read from the plots in the paper and may not be corrected for efficiency but the background given in the paper have been subtracted. Source code: BESIII_2013_I1261765.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) -> Lambda Sigmabar+- pi-+
10 class BESIII_2013_I1261765 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2013_I1261765);
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==100443);
23 declare(ufs, "UFS");
24 DecayedParticles psi(ufs);
25 psi.addStable( PID::PI0);
26 psi.addStable( PID::K0S);
27 psi.addStable( PID::SIGMAPLUS);
28 psi.addStable( PID::SIGMAMINUS);
29 psi.addStable(-PID::SIGMAPLUS);
30 psi.addStable(-PID::SIGMAMINUS);
31 psi.addStable( PID::LAMBDA);
32 psi.addStable(-PID::LAMBDA);
33 declare(psi, "psi");
34 for(unsigned int ix=0;ix<3;++ix)
35 book(_h[ix],1,1,1+ix);
36 }
37
38
39 /// Perform the per-event analysis
40 void analyze(const Event& event) {
41 static const map<PdgId,unsigned int> & mode1 = { { 3122,1}, {-3222,1}, { 211,1} };
42 static const map<PdgId,unsigned int> & mode1CC = { {-3122,1}, { 3222,1}, {-211,1} };
43 static const map<PdgId,unsigned int> & mode2 = { { 3122,1}, {-3112,1}, {-211,1} };
44 static const map<PdgId,unsigned int> & mode2CC = { {-3122,1}, { 3112,1}, { 211,1} };
45 DecayedParticles psi = apply<DecayedParticles>(event, "psi");
46 for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
47 int ipi=211, isigma=-3222,sign=1;
48 if(psi.modeMatches(ix,3,mode1)) {
49 sign = 1;
50 }
51 else if(psi.modeMatches(ix,3,mode1CC)) {
52 sign = -1;
53 }
54 else if(psi.modeMatches(ix,3,mode2)) {
55 ipi=-211;
56 isigma=-3112;
57 sign = 1;
58 }
59 else if(psi.modeMatches(ix,3,mode2CC)) {
60 ipi=-211;
61 isigma=-3112;
62 sign = -1;
63 }
64 else
65 continue;
66 const Particle & lam = psi.decayProducts()[ix].at( sign*3122 )[0];
67 const Particle & pim = psi.decayProducts()[ix].at( sign*ipi )[0];
68 const Particle & sigma = psi.decayProducts()[ix].at( sign*isigma)[0];
69 _h[0]->fill((lam.momentum()+pim .momentum()).mass());
70 _h[1]->fill((pim.momentum()+sigma.momentum()).mass());
71 _h[2]->fill((lam.momentum()+sigma.momentum()).mass());
72 }
73 }
74
75
76 /// Normalise histograms etc., after the run
77 void finalize() {
78 for(unsigned int ix=0;ix<3;++ix)
79 normalize(_h[ix],1.,false);
80 }
81
82 /// @}
83
84
85 /// @name Histograms
86 /// @{
87 Histo1DPtr _h[3];
88 /// @}
89
90
91 };
92
93
94 RIVET_DECLARE_PLUGIN(BESIII_2013_I1261765);
95
96}
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