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OPAL_1998_S3702294

Production of $f_0(980)$, $f_2(1270)$ and $\phi(1020)$ in hadronic $Z^0$ decay
Experiment: OPAL (LEP 1)
Inspire ID: 467092
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Eur.Phys.J.C4:19-28,1998
  • hep-ex/9802013
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)

Inclusive production of the $f_0(980)$, $f_2(1270)$ and $\phi(1020)$ resonances studied in a sample of 4.3 million hadronic $Z^0$ decays from the OPAL experiment at LEP. Fragmentation functions are reported for the three states.

Source code: OPAL_1998_S3702294.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/Beam.hh"
 4#include "Rivet/Projections/FinalState.hh"
 5#include "Rivet/Projections/ChargedFinalState.hh"
 6#include "Rivet/Projections/UnstableParticles.hh"
 7
 8namespace Rivet {
 9
10
11  /// @brief OPAL f0,f2 and phi fragmentation function paper
12  ///
13  /// @author Peter Richardson
14  class OPAL_1998_S3702294 : public Analysis {
15  public:
16
17    RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_1998_S3702294);
18
19
20    /// @name Analysis methods
21    /// @{
22
23    void init() {
24      declare(Beam(), "Beams");
25      declare(ChargedFinalState(), "FS");
26      declare(UnstableParticles(), "UFS");
27      book(_histXpf0  , 2, 1, 1);
28      book(_histXpf2  , 2, 1, 2);
29      book(_histXpPhi , 2, 1, 3);
30    }
31
32
33    void analyze(const Event& e) {
34      // First, veto on leptonic events by requiring at least 4 charged FS particles
35      const FinalState& fs = apply<FinalState>(e, "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>(e, "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 of unstable particles to get particle spectra
52      const UnstableParticles& ufs = apply<UnstableParticles>(e, "UFS");
53
54      for (const Particle& p : ufs.particles()) {
55        const int id = p.abspid();
56        double xp = p.p3().mod()/meanBeamMom;
57        switch (id) {
58        case 9010221:
59          _histXpf0->fill(xp);
60          break;
61        case 225:
62          _histXpf2->fill(xp);
63          break;
64        case 333:
65          _histXpPhi->fill(xp);
66          break;
67        }
68      }
69    }
70
71
72    /// Finalize
73    void finalize() {
74      scale(_histXpf0 , 1./sumOfWeights());
75      scale(_histXpf2 , 1./sumOfWeights());
76      scale(_histXpPhi, 1./sumOfWeights());
77    }
78
79    /// @}
80
81
82  private:
83
84    /// @{
85    Histo1DPtr _histXpf0;
86    Histo1DPtr _histXpf2;
87    Histo1DPtr _histXpPhi;
88    /// @}
89
90  };
91
92
93
94  RIVET_DECLARE_ALIASED_PLUGIN(OPAL_1998_S3702294, OPAL_1998_I467092);
95
96}