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DELPHI_1995_I377487

Spectrum for $K^0,\bar{K}^0$ and $K^{*\pm}$ production in hadronic $Z^0$ decays
Experiment: DELPHI (LEP)
Inspire ID: 377487
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C65 (1995) 587-602
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 spectra for $K^0,\bar{K}^0$ and $K^{*\pm}$ production in hadronic $Z^0$ decays. The other spectra in the paper are superseded by those in DELPHI_1999_S3960137 and are therefore not implemented.

Source code: DELPHI_1995_I377487.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5#include "Rivet/Projections/UnstableParticles.hh"
 6#include "Rivet/Projections/Beam.hh"
 7
 8namespace Rivet {
 9
10
11  /// @brief kaon spectra at LEP1
12  class DELPHI_1995_I377487 : public Analysis {
13  public:
14
15    /// Constructor
16    RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_1995_I377487);
17
18
19    /// @name Analysis methods
20    //@{
21
22    /// Book histograms and initialise projections before the run
23    void init() {
24      declare(Beam(), "Beams");
25      declare(ChargedFinalState(), "FS");
26      declare(UnstableParticles(), "UFS");
27
28      // Book histograms
29      book(_h_K0_x , 8, 1, 1);
30      book(_h_K0_xi, 9, 1, 1);
31      book(_h_Ks_x ,10, 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::pid==130 or
60						Cuts::pid==310 or
61						Cuts::abspid==323)) {
62        double xp = p.p3().mod()/meanBeamMom;
63	if(abs(p.pid())==323)
64	  _h_Ks_x->fill(xp);
65	else {
66	  _h_K0_x->fill(xp);
67	  _h_K0_xi->fill(-log(xp));
68	}
69      }
70    }
71
72
73    /// Normalise histograms etc., after the run
74    void finalize() {
75
76      scale(_h_K0_x, 1./sumOfWeights());
77      scale(_h_K0_xi, 1./sumOfWeights());
78      scale(_h_Ks_x, 1./sumOfWeights());
79    }
80
81    //@}
82
83
84    /// @name Histograms
85    //@{
86    Histo1DPtr _h_K0_x,_h_K0_xi,_h_Ks_x;
87    //@}
88
89
90  };
91
92
93  // The hook for the plugin system
94  RIVET_DECLARE_PLUGIN(DELPHI_1995_I377487);
95
96
97}