Rivet analyses referenceARGUS_1991_I315059$D^0$, $D^+$, $D^{*+}$ production in $e^+e^-$ annihilation at 10.47 GeV, and $B$ decaysExperiment: ARGUS (DORIS) Inspire ID: 315059 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the scaled momentum spectra for $D^0$, $D^+$, $D^{*+}$ production in $e^+e^-$ annihilation at 10.47 GeV, and from $B$ decays at the $\Upsilon(4S)$. Source code: ARGUS_1991_I315059.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/Beam.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief ARGUS D0, D+, D*+ production
10 class ARGUS_1991_I315059 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1991_I315059);
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(UnstableParticles(), "UFS");
25 declare(Beam(), "Beams");
26
27 // Book histograms
28 book(_n_D0 , 1,1,1);
29 book(_n_Dp , 1,1,2);
30 book(_n_DStar, 1,1,3);
31
32 book(_h_x_D0 , 2,1,1);
33 book(_h_x_Dp , 3,1,1);
34 book(_h_x_DStar, 4,1,1);
35
36 book(_h_p_D0 , 5,1,1);
37 book(_h_p_Dp , 6,1,1);
38 book(_h_p_DStar, 7,1,1);
39
40 book(_c_cont, "/TMP/c_cont");
41 book(_c_ups , "/TMP/c_ups");
42 }
43
44
45 /// Perform the per-event analysis
46 void analyze(const Event& event) {
47 // Get beams and average beam momentum
48 const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
49 const double meanBeamMom = ( beams.first.p3().mod() +
50 beams.second.p3().mod() ) / 2.0;
51 MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
52 // Find the Upsilon(4S) among the unstables
53 const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
54 Particles upsilons = ufs.particles(Cuts::pid==300553);
55 // Continuum
56 if (upsilons.empty()) {
57 _c_cont->fill();
58 MSG_DEBUG("No Upsilons found => continuum event");
59 for (const Particle &p : ufs.particles(Cuts::abspid==411 or Cuts::abspid==421 or Cuts::abspid==413)) {
60 double xp = p.p3().mod()/sqrt(sqr(meanBeamMom)-sqr(p.mass()));
61 if(p.abspid()==421) {
62 _h_x_D0->fill(xp);
63 _n_D0->fill(Ecms);
64 }
65 else if(p.abspid()==411) {
66 _h_x_Dp->fill(xp);
67 _n_Dp->fill(Ecms);
68 }
69 else if(p.abspid()==413) {
70 _h_x_DStar->fill(xp);
71 _n_DStar->fill(Ecms);
72 }
73 }
74 }
75 // upsilon decay
76 else {
77 for (const Particle& ups : upsilons) {
78 _c_ups->fill();
79 Particles unstable;
80 // Find the decay products we want
81 findDecayProducts(ups, unstable);
82 // boost to rest frame (if required)
83 LorentzTransform cms_boost;
84 if (ups.p3().mod() > 1*MeV) {
85 cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
86 }
87 for (const Particle& p : unstable) {
88 const FourMomentum p2 = cms_boost.transform(p.momentum());
89 double modp = p2.p3().mod();
90 if(p.abspid()==421) {
91 _h_p_D0->fill(modp);
92 }
93 else if(p.abspid()==411) {
94 _h_p_Dp->fill(modp);
95 }
96 else if(p.abspid()==413) {
97 _h_p_DStar->fill(modp);
98 }
99 }
100 }
101 }
102 }
103
104 /// Recursively walk the decay tree to find decay products of @a p
105 void findDecayProducts(Particle mother, Particles& unstable) {
106 for(const Particle & p: mother.children()) {
107 const int id = p.abspid();
108 if (id == 411 || id == 421) {
109 unstable.push_back(p);
110 }
111 else if (id == 413 ) {
112 unstable.push_back(p);
113 findDecayProducts(p, unstable);
114 }
115 else if(!p.children().empty()) {
116 findDecayProducts(p, unstable);
117 }
118 }
119 }
120
121 /// Normalise histograms etc., after the run
122 void finalize() {
123 // brs for the decays used (PDG 2018)
124 double brD0 = 0.0389;
125 double brDp = 0.0898;
126 double brDStar = 0.677;
127 if (_c_cont->numEntries()!=0) {
128 scale(_n_D0 , 1./sumOfWeights()*crossSection()/nanobarn);
129 scale(_n_Dp , 1./sumOfWeights()*crossSection()/nanobarn);
130 scale(_n_DStar , 1./sumOfWeights()*crossSection()/nanobarn);
131 scale(_h_x_D0 , brD0/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
132 scale(_h_x_Dp , brDp/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
133 scale(_h_x_DStar, brD0*brDStar/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
134 }
135 if (_c_ups->numEntries()!=0) {
136 scale(_h_p_D0 , 1e3*0.5*brD0/ *_c_ups);
137 scale(_h_p_Dp , 1e3*0.5*brDp/ *_c_ups);
138 scale(_h_p_DStar, 1e3*0.5*brD0*brDStar/ *_c_ups);
139 }
140 }
141
142 /// @}
143
144
145 /// @name Histograms
146 /// @{
147 BinnedHistoPtr<string> _n_D0,_n_Dp,_n_DStar;
148 Histo1DPtr _h_x_D0,_h_x_Dp,_h_x_DStar;
149 Histo1DPtr _h_p_D0,_h_p_Dp,_h_p_DStar;
150 CounterPtr _c_cont, _c_ups;
151 const string Ecms = "10.6";
152 /// @}
153
154
155 };
156
157
158 RIVET_DECLARE_PLUGIN(ARGUS_1991_I315059);
159
160
161}
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