Rivet analyses referenceCLEOII_1994_I356001Pion Mass spectra for Υ(3S)→Υ(1,2S)π+π−, Υ(3S)→Υ(1,2S)π0π0 and Υ(2S)→Υ(1S)π+π−Experiment: CLEOII (CESR) Inspire ID: 356001 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the pion mass spectra for the decays Υ(3S)→Υ(1,2S)π+π−, Υ(3S)→Υ(1,2S)π0π0 and Υ(2S)→Υ(1S)π+π− by the CLEO-II collaboration. Source code: CLEOII_1994_I356001.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4
5namespace Rivet {
6
7
8 /// @brief Add a short analysis description here
9 class CLEOII_1994_I356001 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1994_I356001);
14
15
16 /// @name Analysis methods
17 /// @{
18
19 /// Book histograms and initialise projections before the run
20 void init() {
21 // Initialise and register projections
22 declare(UnstableParticles(),"UFS");
23 // Histograms
24 book(_n_2S,"/TMP/n_2S");
25 book(_n_3S,"/TMP/n_3S");
26 book(_h_3S_1S_neutral,1,1,1);
27 book(_h_3S_2S_neutral,1,1,2);
28 book(_h_3S_1S_ex ,2,1,1);
29 book(_h_3S_1S_in ,2,1,2);
30 book(_h_3S_2S_ex ,3,1,1);
31 book(_h_3S_2S_in ,3,1,2);
32 book(_h_2S_1S_ex ,4,1,1);
33 book(_h_2S_1S_in ,4,1,2);
34 }
35
36 void findDecayProducts(const Particle & mother,
37 unsigned int & nstable,
38 Particles& pip, Particles& pim,
39 Particles& pi0, Particles & onium) {
40 for(const Particle & p : mother.children()) {
41 int id = p.pid();
42 if ( id == PID::PIMINUS) {
43 pim.push_back(p);
44 ++nstable;
45 }
46 else if (id == PID::PIPLUS) {
47 pip.push_back(p);
48 ++nstable;
49 }
50 else if (id == PID::PI0) {
51 pi0.push_back(p);
52 ++nstable;
53 }
54 else if (abs(id)%1000==553) {
55 onium.push_back(p);
56 ++nstable;
57 }
58 else if ( !p.children().empty() ) {
59 findDecayProducts(p,nstable,pip,pim,pi0,onium);
60 }
61 else
62 ++nstable;
63 }
64 }
65
66 /// Perform the per-event analysis
67 void analyze(const Event& event) {
68 // loop over unstable particles
69 for(const Particle& ups : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==100553 or
70 Cuts::pid==200553)) {
71 if(ups.pid()==200553)
72 _n_3S->fill();
73 else
74 _n_2S->fill();
75 unsigned int nstable(0);
76 Particles pip, pim, pi0, onium;
77 findDecayProducts(ups,nstable,pip,pim,pi0,onium);
78 // check for onium
79 if(onium.size() !=1 || nstable !=3) continue;
80 //pi+pi-
81 if( pip.size()==1 && pim.size() ==1) {
82 double q = (pip[0].momentum()+pim[0].momentum()).mass();
83 if(ups.pid()==200553 && onium[0].pid()==553) {
84 _h_3S_1S_ex->fill(q);
85 _h_3S_1S_in->fill(q);
86 }
87 else if(ups.pid()==200553 && onium[0].pid()==100553) {
88 _h_3S_2S_ex->fill(q);
89 _h_3S_2S_in->fill(q);
90 }
91 else if(ups.pid()==100553 && onium[0].pid()==553) {
92 _h_2S_1S_ex->fill(q);
93 _h_2S_1S_in->fill(q);
94 }
95 }
96 else if(pi0.size()==2) {
97 double q = (pi0[0].momentum()+pi0[1].momentum()).mass();
98 if(ups.pid()==200553 && onium[0].pid()==553) {
99 _h_3S_1S_neutral->fill(q);
100 }
101 else if(ups.pid()==200553 && onium[0].pid()==100553) {
102 _h_3S_2S_neutral->fill(q);
103 }
104
105 }
106 }
107 }
108
109
110 /// Normalise histograms etc., after the run
111 void finalize() {
112 // widths of Upsilon 2S and 3S
113 vector<double> width = {31.98,20.32};
114 scale(_h_3S_2S_neutral, width[1]/ *_n_3S);
115 scale(_h_3S_1S_neutral, width[1]/ *_n_3S);
116 scale(_h_3S_2S_ex , width[1]/ *_n_3S);
117 scale(_h_3S_2S_in , width[1]/ *_n_3S);
118 scale(_h_3S_1S_ex , width[1]/ *_n_3S);
119 scale(_h_3S_1S_in , width[1]/ *_n_3S);
120 scale(_h_2S_1S_ex , width[0]/ *_n_2S);
121 scale(_h_2S_1S_in , width[0]/ *_n_2S);
122 }
123
124 /// @}
125
126
127 /// @name Histograms
128 /// @{
129 CounterPtr _n_3S,_n_2S;
130 Histo1DPtr _h_3S_2S_neutral,_h_3S_1S_neutral;
131 Histo1DPtr _h_3S_2S_ex,_h_3S_2S_in,_h_3S_1S_ex,_h_3S_1S_in;
132 Histo1DPtr _h_2S_1S_ex,_h_2S_1S_in;
133 /// @}
134
135
136 };
137
138
139 RIVET_DECLARE_PLUGIN(CLEOII_1994_I356001);
140
141}
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