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DELPHI_1995_I399737

Spectrum for $\Delta^{++}$ production in hadronic $Z^0$ decays
Experiment: DELPHI (LEP)
Inspire ID: 399737
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B361 (1995) 207-220
Beams: e+ e-
Beam energies: (45.6, 45.6) GeV
Run details:
  • Hadronic Z decay events generated on the Z pole ($\sqrt{s} = 91.2$ GeV)

DELPHI results for the spectrum for $\Delta^{++}$ production in hadronic $Z^0$ decays

Source code: DELPHI_1995_I399737.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/FastJets.hh"
 5#include "Rivet/Projections/FinalState.hh"
 6#include "Rivet/Projections/ChargedFinalState.hh"
 7#include "Rivet/Projections/UnstableParticles.hh"
 8#include "Rivet/Projections/Beam.hh"
 9
10namespace Rivet {
11
12
13  /// @brief Delta++ spectrum
14  class DELPHI_1995_I399737 : public Analysis {
15  public:
16
17    /// Constructor
18    RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_1995_I399737);
19
20
21    /// @name Analysis methods
22    //@{
23
24    /// Book histograms and initialise projections before the run
25    void init() {
26      declare(Beam(), "Beams");
27      declare(ChargedFinalState(), "FS");
28      declare(UnstableParticles(), "UFS");
29
30      // Book histograms
31      book(_h_delta, 1, 1, 1);
32
33    }
34
35
36    /// Perform the per-event analysis
37    void analyze(const Event& event) {
38
39      // First, veto on leptonic events by requiring at least 4 charged FS particles
40      const FinalState& fs = apply<FinalState>(event, "FS");
41      const size_t numParticles = fs.particles().size();
42
43      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
44      if (numParticles < 2) {
45        MSG_DEBUG("Failed leptonic event cut");
46        vetoEvent;
47      }
48      MSG_DEBUG("Passed leptonic event cut");
49
50      // Get beams and average beam momentum
51      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
52      const double meanBeamMom = ( beams.first.p3().mod() +
53                                   beams.second.p3().mod() ) / 2.0;
54      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
55
56      // Final state of unstable particles to get particle spectra
57      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
58
59      for (const Particle& p : ufs.particles(Cuts::abspid==2224)) {
60        double xp = p.p3().mod()/meanBeamMom;
61	_h_delta->fill(xp);
62      }
63    }
64
65
66    /// Normalise histograms etc., after the run
67    void finalize() {
68      scale(_h_delta, 1./sumOfWeights());
69    }
70
71    //@}
72
73
74    /// @name Histograms
75    //@{
76    Histo1DPtr _h_delta;
77    //@}
78
79
80  };
81
82
83  // The hook for the plugin system
84  RIVET_DECLARE_PLUGIN(DELPHI_1995_I399737);
85
86
87}