Rivet analyses referenceBESIII_2020_I1795949Cross section for $e^+e^-\to D_s^{(*)+}D_{s1}(2460)^-+\text{c.c.}$Experiment: BESIII (BEPC) Inspire ID: 1795949 Status: VALIDATED Authors:
Beam energies: (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) GeV Run details:
Measurement of the cross section for $e^+e^-\to D_s^{(*)+}D_{s1}(2460)^-+\text{c.c.}$ by the BESIII experiment for centre-of-mass energies between 4.467 and 4.6 GeV. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples. Source code: BESIII_2020_I1795949.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- -> Ds(*) D_s1
10 class BESIII_2020_I1795949 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2020_I1795949);
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 declare(FinalState(), "FS");
24 declare(UnstableParticles(), "UFS");
25
26 // Book histograms
27 book(_c_Ds , 1, 1, 1);
28 book(_c_DsStar, 2, 1, 1);
29 for (const string& en : _c_Ds.binning().edges<0>()) {
30 const double end = std::stod(en)*GeV;
31 if (isCompatibleWithSqrtS(end)) {
32 _ecms = en;
33 break;
34 }
35 }
36 if(_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
37 }
38
39 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
40 for(const Particle &child : p.children()) {
41 if(child.children().empty()) {
42 nRes[child.pid()]-=1;
43 --ncount;
44 }
45 else
46 findChildren(child,nRes,ncount);
47 }
48 }
49
50 /// Perform the per-event analysis
51 void analyze(const Event& event) {
52 const FinalState& fs = apply<FinalState>(event, "FS");
53 // total analyse final state
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 // unstable charm analysis
61 Particles ds = apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==431 or Cuts::abspid==433 or
62 Cuts::abspid==20433);
63 for(unsigned int ix=0;ix<ds.size();++ix) {
64 const Particle& p1 = ds[ix];
65 int id1 = abs(p1.pid());
66 // check fs
67 bool fs = true;
68 for (const Particle & child : p1.children()) {
69 if(child.pid()==p1.pid()) {
70 fs = false;
71 break;
72 }
73 }
74 if(!fs) continue;
75 // find the children
76 map<long,int> nRes = nCount;
77 int ncount = ntotal;
78 findChildren(p1,nRes,ncount);
79 bool matched=false;
80 int sign = p1.pid()/id1;
81 // loop over the other fs particles
82 for(unsigned int iy=ix+1;iy<ds.size();++iy) {
83 const Particle& p2 = ds[iy];
84 fs = true;
85 for (const Particle & child : p2.children()) {
86 if(child.pid()==p2.pid()) {
87 fs = false;
88 break;
89 }
90 }
91 if(!fs) continue;
92 if(p2.pid()/abs(p2.pid())==sign) continue;
93 int id2 = abs(p2.pid());
94 if(!p2.parents().empty() && p2.parents()[0].pid()==p1.pid())
95 continue;
96 map<long,int> nRes2 = nRes;
97 int ncount2 = ncount;
98 findChildren(p2,nRes2,ncount2);
99 if(ncount2!=0) continue;
100 matched=true;
101 for(auto const & val : nRes2) {
102 if(val.second!=0) {
103 matched = false;
104 break;
105 }
106 }
107 if(matched) {
108 if((id1==431 && id2==20433) || (id1==20433 && id2==421)) {
109 _c_Ds->fill(_ecms);
110 }
111 else if((id1==433 && id2==20433) || (id1==20433 && id2==433)) {
112 _c_DsStar->fill(_ecms);
113 }
114 break;
115 }
116 }
117 if(matched) break;
118 }
119 }
120
121
122 /// Normalise histograms etc., after the run
123 void finalize() {
124 double fact = crossSection()/ sumOfWeights()/picobarn;
125 scale(_c_Ds ,fact);
126 scale(_c_DsStar,fact);
127 }
128
129 /// @}
130
131
132 /// @name Histograms
133 /// @{
134 BinnedHistoPtr<string> _c_Ds,_c_DsStar;
135 string _ecms;
136 /// @}
137
138 };
139
140
141 RIVET_DECLARE_PLUGIN(BESIII_2020_I1795949);
142
143}
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