Rivet analyses referenceBABAR_2015_I1383130Cross section for $e^+e^-\to K^+K^-$ between 2.6 and 8 GeVExperiment: BABAR (PEP-II) Inspire ID: 1383130 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the cross section for $e^+e^-\to K^+K^-$ at energies between 2.6 and 8 GeV Source code: BABAR_2015_I1383130.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5
6namespace Rivet {
7
8
9 /// @brief Add a short analysis description here
10 class BABAR_2015_I1383130 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2015_I1383130);
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
26 // Book histograms
27 book(_nkaon, "TMP/kaon");
28
29 }
30
31 /// Perform the per-event analysis
32 void analyze(const Event& event) {
33 const FinalState& fs = apply<FinalState>(event, "FS");
34 if(fs.particles().size()!=2) vetoEvent;
35 for (const Particle& p : fs.particles()) {
36 if(abs(p.pid())!=PID::KPLUS) vetoEvent;
37 }
38 _nkaon->fill();
39 }
40
41
42 /// Normalise histograms etc., after the run
43 void finalize() {
44 double sigma = _nkaon->val();
45 double error = _nkaon->err();
46 sigma *= crossSection()/ sumOfWeights() /picobarn;
47 error *= crossSection()/ sumOfWeights() /picobarn;
48 Scatter2D temphisto(refData(1, 1, 4));
49 Scatter2DPtr mult;
50 book(mult, 1, 1, 4);
51 for (size_t b = 0; b < temphisto.numPoints(); b++) {
52 const double x = temphisto.point(b).x();
53 pair<double,double> ex = temphisto.point(b).xErrs();
54 pair<double,double> ex2 = ex;
55 if(ex2.first ==0.) ex2. first=0.0001;
56 if(ex2.second==0.) ex2.second=0.0001;
57 if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
58 mult->addPoint(x, sigma, ex, make_pair(error,error));
59 }
60 else {
61 mult->addPoint(x, 0., ex, make_pair(0.,.0));
62 }
63 }
64 }
65
66 //@}
67
68
69 /// @name Histograms
70 //@{
71 CounterPtr _nkaon;
72 //@}
73
74
75 };
76
77
78 // The hook for the plugin system
79 RIVET_DECLARE_PLUGIN(BABAR_2015_I1383130);
80
81
82}
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