Rivet analyses referenceBABAR_2013_I1217421Cross section for $e^+e^-\to$ proton and antiproton between 1.877 and 4.25 GeVExperiment: BABAR (PEP-II) Inspire ID: 1217421 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the cross section for $e^+e^-\to p\bar{p}$ using radiative return for energies between 1.877 and 4.25 GeV. Source code: BABAR_2013_I1217421.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5
6namespace Rivet {
7
8
9 /// @brief e+e- > p pbar
10 class BABAR_2013_I1217421 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2013_I1217421);
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(_nproton, "TMP/proton");
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::PROTON) vetoEvent;
37 }
38 _nproton->fill();
39 }
40
41
42 /// Normalise histograms etc., after the run
43 void finalize() {
44 double sigma = _nproton->val();
45 double error = _nproton->err();
46 sigma *= crossSection()/ sumOfWeights() /picobarn;
47 error *= crossSection()/ sumOfWeights() /picobarn;
48 Estimate1DPtr mult;
49 book(mult, 1, 1, 1);
50 for (auto& b : mult->bins()) {
51 if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
52 b.set(sigma, error);
53 }
54 }
55 }
56
57 /// @}
58
59
60 /// @name Histograms
61 /// @{
62 CounterPtr _nproton;
63 /// @}
64
65
66 };
67
68
69 RIVET_DECLARE_PLUGIN(BABAR_2013_I1217421);
70
71
72}
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