Rivet analyses referenceBESIII_2023_I2674370Cross section for $e^+e^-\to pK^-\bar\Lambda^0 +\text{c.c.}$ for $\sqrt{s}$ from 4.009 and 4.951 GeVExperiment: BESIII (BEPC) Inspire ID: 2674370 Status: VALIDATED NOHEPDATA Authors:
Beam energies: (2.0, 2.0); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3); (2.4, 2.4); (2.4, 2.4); (2.4, 2.4); (2.4, 2.4); (2.5, 2.5); (2.5, 2.5) GeV Run details:
Measurement of the cross section for $e^+e^-\to pK^-\bar\Lambda^0 +\text{c.c.}$ for $\sqrt{s}$ from 4.009 and 4.951 GeV by the BESIII collaboration. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples. Source code: BESIII_2023_I2674370.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief e+ e- -> p K- Lambdabar +cc
10 class BESIII_2023_I2674370 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2023_I2674370);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22
23 // Initialise and register projections
24 declare(FinalState(), "FS");
25 declare(UnstableParticles(Cuts::abspid==3122), "UFS");
26 // counter
27 book(_sigma, 1, 1, 1);
28 for (const string& en : _sigma.binning().edges<0>()) {
29 const double end = std::stod(en)*GeV;
30 if (isCompatibleWithSqrtS(end)) {
31 _ecms = en;
32 break;
33 }
34 }
35 if (_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
36 }
37
38 void findChildren(const Particle& p,map<long,int>& nRes, int &ncount) {
39 for (const Particle& child : p.children()) {
40 if (child.children().empty()) {
41 nRes[child.pid()]-=1;
42 --ncount;
43 }
44 else {
45 findChildren(child,nRes,ncount);
46 }
47 }
48 }
49
50 /// Perform the per-event analysis
51 void analyze(const Event& event) {
52 const FinalState& fs = apply<FinalState>(event, "FS");
53
54 map<long,int> nCount;
55 int ntotal(0);
56 for (const Particle& p : fs.particles()) {
57 nCount[p.pid()] += 1;
58 ++ntotal;
59 }
60 const FinalState& ufs = apply<FinalState>(event, "UFS");
61 // loop over Lambda baryons
62 for (const Particle& lam : ufs.particles()) {
63 bool matched = false;
64 map<long,int> nRes=nCount;
65 int ncount = ntotal;
66 findChildren(lam,nRes,ncount);
67 int sign = lam.pid()/lam.abspid();
68 if (ncount==2) {
69 matched=true;
70 for (auto const& val : nRes) {
71 if (val.first== sign*321 || val.first==-sign*2212) {
72 if (val.second!=1) {
73 matched = false;
74 break;
75 }
76 }
77 else if (val.second!=0) {
78 matched = false;
79 break;
80 }
81 }
82 }
83 if (matched) {
84 _sigma->fill(_ecms);
85 break;
86 }
87 }
88 }
89
90
91 /// Normalise histograms etc., after the run
92 void finalize() {
93 scale(_sigma, crossSection()/ sumOfWeights() /picobarn);
94 }
95
96 /// @}
97
98
99 /// @name Histograms
100 /// @{
101 BinnedHistoPtr<string> _sigma;
102 string _ecms;
103 /// @}
104
105
106 };
107
108
109 RIVET_DECLARE_PLUGIN(BESIII_2023_I2674370);
110
111}
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