Rivet analyses referenceBELLE_2020_I1813380Mass distributions in $\Lambda_c^+\to \eta\Lambda\pi^+$Experiment: BELLE (KEKB) Inspire ID: 1813380 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $\Lambda_c^+\to \eta\Lambda\pi^+$ by BELLE. The data were read from the plots in the paper and may not have been corrected for efficiency/acceptance. Source code: BELLE_2020_I1813380.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 Lambda_c+ -> eta Lambda pi+
10 class BELLE_2020_I1813380 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2020_I1813380);
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::abspid==4122);
24 declare(ufs, "UFS");
25 DecayedParticles LAMBDAC(ufs);
26 LAMBDAC.addStable(PID::PI0);
27 LAMBDAC.addStable(PID::K0S);
28 LAMBDAC.addStable(PID::ETA);
29 LAMBDAC.addStable(PID::LAMBDA);
30 LAMBDAC.addStable(-PID::LAMBDA);
31 declare(LAMBDAC, "LAMBDAC");
32 // histograms
33 for(unsigned int ix=0;ix<2;++ix)
34 book(_h[ix],1,1,1+ix);
35 }
36
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { PID::LAMBDA,1}, { 211,1}, { 221,1}};
41 static const map<PdgId,unsigned int> & modeCC = { {-PID::LAMBDA,1}, {-211,1}, { 221,1}};
42 DecayedParticles LAMBDAC = apply<DecayedParticles>(event, "LAMBDAC");
43 // loop over particles
44 for(unsigned int ix=0;ix<LAMBDAC.decaying().size();++ix) {
45 int sign = 1;
46 if (LAMBDAC.decaying()[ix].pid()>0 && LAMBDAC.modeMatches(ix,3,mode)) {
47 sign=1;
48 }
49 else if (LAMBDAC.decaying()[ix].pid()<0 && LAMBDAC.modeMatches(ix,3,modeCC)) {
50 sign=-1;
51 }
52 else
53 continue;
54 const Particle & lam = LAMBDAC.decayProducts()[ix].at( sign*PID::LAMBDA)[0];
55 const Particle & eta = LAMBDAC.decayProducts()[ix].at( 221)[0];
56 const Particle & pip = LAMBDAC.decayProducts()[ix].at( sign*211)[0];
57 _h[0]->fill((lam.momentum()+eta.momentum()).mass());
58 _h[1]->fill((lam.momentum()+pip.momentum()).mass());
59 }
60 }
61
62
63 /// Normalise histograms etc., after the run
64 void finalize() {
65 for(unsigned int ix=0;ix<2;++ix)
66 normalize(_h[ix],1.,false);
67 }
68
69 /// @}
70
71
72 /// @name Histograms
73 /// @{
74 Histo1DPtr _h[2];
75 /// @}
76
77
78 };
79
80
81 RIVET_DECLARE_PLUGIN(BELLE_2020_I1813380);
82
83}
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