Rivet analyses referenceHRS_1992_I339573Spectrum for $\Lambda$ production at 29 GeVExperiment: HRS (PEP) Inspire ID: 339573 Status: VALIDATED Authors:
Beam energies: (14.5, 14.5) GeV Run details:
Spectrum for the production of $\Lambda$ baryons at 29 GeV measured by the HRS experiment. Source code: HRS_1992_I339573.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5#include "Rivet/Projections/Beam.hh"
6
7namespace Rivet {
8
9
10 /// @brief Add a short analysis description here
11 class HRS_1992_I339573 : public Analysis {
12 public:
13
14 /// Constructor
15 RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1992_I339573);
16
17
18 /// @name Analysis methods
19 //@{
20
21 /// Book histograms and initialise projections before the run
22 void init() {
23 declare(Beam(), "Beams");
24 declare(FinalState(), "FS");
25 declare(UnstableParticles(), "UFS");
26
27 // Book histograms
28 book(_h_lambda, 1 , 1, 1);
29 }
30
31
32 /// Perform the per-event analysis
33 void analyze(const Event& event) {
34 // First, veto on leptonic events by requiring at least 4 charged FS particles
35 const FinalState& fs = apply<FinalState>(event, "FS");
36 const size_t numParticles = fs.particles().size();
37
38 // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
39 if (numParticles < 2) {
40 MSG_DEBUG("Failed leptonic event cut");
41 vetoEvent;
42 }
43 MSG_DEBUG("Passed leptonic event cut");
44
45 // Get beams and average beam momentum
46 const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
47 const double meanBeamMom = ( beams.first.p3().mod() +
48 beams.second.p3().mod() ) / 2.0;
49 MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
50
51 // Final state to get particle spectra
52 for( const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==3122)) {
53 double xE = p.E()/meanBeamMom;
54 _h_lambda->fill(xE);
55 }
56
57 }
58
59
60 /// Normalise histograms etc., after the run
61 void finalize() {
62
63 double fact = sqr(sqrtS())/GeV2*crossSection()/nanobarn/sumOfWeights();
64 scale(_h_lambda, fact);
65 }
66
67 //@}
68
69
70 /// @name Histograms
71 //@{
72 Histo1DPtr _h_lambda;
73 //@}
74
75
76 };
77
78
79 // The hook for the plugin system
80 RIVET_DECLARE_PLUGIN(HRS_1992_I339573);
81
82
83}
|