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TPC_1984_I200105

$\phi$ spectrum at 29 GeV
Experiment: TPC (PEP)
Inspire ID: 200105
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev.Lett. 52 (1984) 2201, 1984
Beams: e+ e-
Beam energies: (14.5, 14.5) GeV
Run details:
  • e+e- to hadrons at 29 GeV

Measurement of the $\phi$ spectra at 29 GeV by the TPC experiment.

Source code: TPC_1984_I200105.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/UnstableParticles.hh"
 5#include "Rivet/Projections/FastJets.hh"
 6#include "Rivet/Projections/Thrust.hh"
 7#include "Rivet/Projections/Beam.hh"
 8
 9namespace Rivet {
10
11
12  /// @brief Add a short analysis description here
13  class TPC_1984_I200105 : public Analysis {
14  public:
15
16    /// Constructor
17    RIVET_DEFAULT_ANALYSIS_CTOR(TPC_1984_I200105);
18
19
20    /// @name Analysis methods
21    //@{
22
23    /// Book histograms and initialise projections before the run
24    void init() {
25      declare(Beam(), "Beams");
26      const FinalState cfs(Cuts::charge != 0);
27      declare(cfs, "FS");
28      const Thrust thrust(cfs);
29      declare(thrust, "Thrust");
30      declare(UnstableParticles(), "UFS");
31
32      // Book histograms
33      book(_h_x , 1, 1, 1);
34      book(_h_pt, 3, 1, 1);
35
36    }
37
38
39    /// Perform the per-event analysis
40    void analyze(const Event& event) {
41      // require 5 charged particles
42      const FinalState& fs = apply<FinalState>(event, "FS");
43      if(fs.size()<3) vetoEvent;
44      // Get beams and average beam momentum
45      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
46      const double meanBeamMom = ( beams.first.p3().mod() +
47                                   beams.second.p3().mod() ) / 2.0;
48      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
49      // calc thrust
50      const Thrust& thrust = apply<Thrust>(event, "Thrust");
51      Vector3 axis = thrust.thrustAxis();
52      // Final state of unstable particles to get particle spectra
53      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
54      for (const Particle& p : ufs.particles(Cuts::pid==333)) {
55        double xE = p.E()/meanBeamMom;
56	double pT2 = p.p3().mod2()-sqr(axis.dot(p.p3()));
57	_h_x ->fill(xE );
58	_h_pt->fill(pT2);
59      }
60    }
61
62
63    /// Normalise histograms etc., after the run
64    void finalize() {
65
66      scale(_h_x, 1./sumOfWeights());
67      scale(_h_pt, 1./sumOfWeights());
68    }
69
70    //@}
71
72
73    /// @name Histograms
74    //@{
75    Histo1DPtr _h_x,_h_pt;
76    //@}
77
78
79  };
80
81
82  // The hook for the plugin system
83  RIVET_DECLARE_PLUGIN(TPC_1984_I200105);
84
85
86}