Rivet analyses referenceBABAR_2021_I1844422Cross sections for $e^+e^-\to 2\pi^+2\pi^-3\pi^0$ and $2\pi^+2\pi^-2\pi^0\eta$ from threshold to 4.5 GeVExperiment: BABAR (PEP-II) Inspire ID: 1844422 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the cross sections for $e^+e^-\to 2\pi^+2\pi^-3\pi^0$ and $2\pi^+2\pi^-2\pi^0\eta$ from threshold to 4.5 GeV by BaBar. The $2\pi^+2\pi^-\eta$, $\omega\pi^0\eta$, $\pi^+\pi^-2\pi^0\omega$, $\pi^+\pi^-2\pi^0\eta$ resonant subprocesses are also measured. Source code: BABAR_2021_I1844422.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- > 2pi+ 2pi- 3pi0 and 2pi+ 2pi- 2pi0 eta
10 class BABAR_2021_I1844422 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2021_I1844422);
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(), "UFS");
26 book(_c_2pip2pim3pi0 ,"TMP/2pip2pim3pi0" );
27 book(_c_2pip2pimeta ,"TMP/2pip2pimeta" );
28 book(_c_omegapi0eta ,"TMP/omegapi0eta" );
29 book(_c_pippim2pi0omega,"TMP/pippim2pi0omega");
30 book(_c_pippim2pi0eta ,"TMP/pippim2pi0eta" );
31 book(_c_2pip2pim2pi0eta,"TMP/2pip2pim2pi0eta");
32 }
33
34 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
35 for(const Particle &child : p.children()) {
36 if(child.children().empty()) {
37 --nRes[child.pid()];
38 --ncount;
39 }
40 else
41 findChildren(child,nRes,ncount);
42 }
43 }
44
45 /// Perform the per-event analysis
46 void analyze(const Event& event) {
47 const FinalState& fs = apply<FinalState>(event, "FS");
48 map<long,int> nCount;
49 int ntotal(0);
50 for (const Particle& p : fs.particles()) {
51 nCount[p.pid()] += 1;
52 ++ntotal;
53 }
54 if(ntotal==7 && nCount[211]==2 && nCount[-211]==2 && nCount[111]==3)
55 _c_2pip2pim3pi0->fill();
56 // intermediate omega and eta mesons
57 Particles unstable = apply<FinalState>(event, "UFS").particles(Cuts::pid==223 or Cuts::pid==221);
58 for (const Particle& p : unstable) {
59 if(p.children().empty()) continue;
60 map<long,int> nRes = nCount;
61 int ncount = ntotal;
62 findChildren(p,nRes,ncount);
63 // eta
64 if(p.pid()==221) {
65 if(ncount==4) {
66 // 2pi+2pi- eta
67 if(nRes[211]==2 && nRes[-211]==2 ) {
68 _c_2pip2pimeta->fill();
69 }
70 // pi+pi- 2pi0 eta
71 else if(nRes[211]==1 && nRes[-211]==1 && nRes[111]==2 ) {
72 _c_pippim2pi0eta->fill();
73 }
74 }
75 else if(ncount==6) {
76 // 2pi+ 2pi- 2pi0 eta
77 if(nRes[211]==2 && nRes[-211]==2 && nRes[111]==2 ) {
78 _c_2pip2pim2pi0eta->fill();
79 }
80 }
81 }
82 // omega
83 else if(p.pid()==223) {
84 // pi+pi- 2pi0 omega
85 if(ncount==4 && nRes[211]==1 && nRes[-211]==1 && nRes[111]==2 ) {
86 _c_pippim2pi0omega->fill();
87 }
88 }
89 // mode with both eta and omega
90 // pi0 omega eta
91 for (const Particle& p2 : unstable ) {
92 if(p2.pid()==p.pid()) continue;
93 map<long,int> nResB = nRes;
94 int ncountB = ncount;
95 findChildren(p2,nResB,ncountB);
96 if(ncountB!=1) continue;
97 bool matched = true;
98 for(auto const & val : nResB) {
99 if(abs(val.first)==111) {
100 if(val.second !=1) {
101 matched = false;
102 break;
103 }
104 }
105 else if(val.second!=0) {
106 matched = false;
107 break;
108 }
109 }
110 if(matched) {
111 _c_omegapi0eta->fill();
112 break;
113 }
114 }
115 }
116 }
117
118
119 /// Normalise histograms etc., after the run
120 void finalize() {
121 for(unsigned int ix=1;ix<7;++ix) {
122 double sigma = 0., error = 0.;
123 if(ix==1) {
124 sigma = _c_2pip2pim3pi0->val();
125 error = _c_2pip2pim3pi0->err();
126 }
127 else if(ix==2) {
128 sigma = _c_2pip2pimeta->val();
129 error = _c_2pip2pimeta->err();
130 }
131 else if(ix==3) {
132 sigma = _c_omegapi0eta->val();
133 error = _c_omegapi0eta->err();
134 }
135 else if(ix==4) {
136 sigma = _c_pippim2pi0omega->val();
137 error = _c_pippim2pi0omega->err();
138 }
139 else if(ix==5) {
140 sigma = _c_pippim2pi0eta->val();
141 error = _c_pippim2pi0eta->err();
142 }
143 else if(ix==6) {
144 sigma = _c_2pip2pim2pi0eta->val();
145 error = _c_2pip2pim2pi0eta->err();
146 }
147 sigma *= crossSection()/ sumOfWeights() /nanobarn;
148 error *= crossSection()/ sumOfWeights() /nanobarn;
149 Estimate1DPtr mult;
150 book(mult, ix, 1, 1);
151 for (auto& b : mult->bins()) {
152 if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
153 b.set(sigma, error);
154 }
155 }
156 }
157 }
158
159 ///@}
160
161
162 /// @name Histograms
163 ///@{
164 CounterPtr _c_2pip2pim3pi0, _c_2pip2pimeta, _c_omegapi0eta,
165 _c_pippim2pi0omega, _c_pippim2pi0eta, _c_2pip2pim2pi0eta;
166 ///@}
167
168
169 };
170
171
172 RIVET_DECLARE_PLUGIN(BABAR_2021_I1844422);
173
174}
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