Rivet analyses referenceBABAR_2009_I797507Measurement of $R_b$ for energies between 10.541 and 11.206 GeVExperiment: BABAR (PEP-II) Inspire ID: 797507 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of $R_b$ in $e^+e^-$ collisions by BaBar for energies between 10.541 and 11.206 GeV. The individual bottom hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalculated if runs are combined. Source code: BABAR_2009_I797507.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 measurement of R_b between 10.541 and 11.206 GeV
10 class BABAR_2009_I797507 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2009_I797507);
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
27 // Book histograms
28 book(_c_hadrons, "/TMP/sigma_hadrons");
29 book(_c_muons , "/TMP/sigma_muons");
30 }
31
32
33 /// Perform the per-event analysis
34 void analyze(const Event& event) {
35 const FinalState& fs = apply<FinalState>(event, "FS");
36 map<long,int> nCount;
37 int ntotal(0);
38 for (const Particle& p : fs.particles()) {
39 nCount[p.pid()] += 1;
40 ++ntotal;
41 }
42 bool isBottom(false);
43 const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
44 for (const Particle& p : ufs.particles()) {
45 if (PID::isBottomHadron(p.pid())) {
46 isBottom = true;
47 break;
48 }
49 }
50
51 // mu+mu- + photons
52 if(nCount[-13]==1 and nCount[13]==1 &&
53 ntotal==2+nCount[22])
54 _c_muons->fill();
55 // everything else
56 else if(isBottom) {
57 _c_hadrons->fill();
58 }
59 }
60
61
62 /// Normalise histograms etc., after the run
63 void finalize() {
64 Scatter1D R = *_c_hadrons/ *_c_muons;
65 double rval = R.point(0).x();
66 pair<double,double> rerr = R.point(0).xErrs();
67 double fact = crossSection()/ sumOfWeights() /picobarn;
68 double sig_h = _c_hadrons->val()*fact;
69 double err_h = _c_hadrons->err()*fact;
70 double sig_m = _c_muons ->val()*fact;
71 double err_m = _c_muons ->err()*fact;
72 Scatter2D temphisto(refData(1, 1, 1));
73 Scatter2DPtr hadrons;
74 book(hadrons, "sigma_hadrons");
75 Scatter2DPtr muons;
76 book(muons, "sigma_muons" );
77 Scatter2DPtr mult;
78 book(mult, 1, 1, 1);
79 for (size_t b = 0; b < temphisto.numPoints(); b++) {
80 const double x = temphisto.point(b).x();
81 pair<double,double> ex = temphisto.point(b).xErrs();
82 pair<double,double> ex2 = ex;
83 if(ex2.first ==0.) ex2. first=0.0001;
84 if(ex2.second==0.) ex2.second=0.0001;
85 if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
86 mult ->addPoint(x, rval, ex, rerr);
87 hadrons->addPoint(x, sig_h, ex, make_pair(err_h,err_h));
88 muons ->addPoint(x, sig_m, ex, make_pair(err_m,err_m));
89 }
90 else {
91 mult ->addPoint(x, 0., ex, make_pair(0.,.0));
92 hadrons->addPoint(x, 0., ex, make_pair(0.,.0));
93 muons ->addPoint(x, 0., ex, make_pair(0.,.0));
94 }
95 }
96 }
97
98 //@}
99
100
101 /// @name Histograms
102 //@{
103 CounterPtr _c_hadrons, _c_muons;
104 //@}
105
106
107 };
108
109
110 // The hook for the plugin system
111 RIVET_DECLARE_PLUGIN(BABAR_2009_I797507);
112
113
114}
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