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TASSO_1986_I230950

$\pi^0$ spectrum in $e^+e^-$ at 34.4 GeV
Experiment: TASSO (Petra)
Inspire ID: 230950
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C33 (1986) 13, 1986
Beams: e+ e-
Beam energies: (17.2, 17.2) GeV
Run details:
  • e+ e- to hadrons

Measurement of the $\pi^0$ spectrum in $e^+e^-$ collisions for a centre-of-mass energy of 34.4 GeV by the TASSO experiment at Petra.

Source code: TASSO_1986_I230950.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4#include "Rivet/Projections/Beam.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief Add a short analysis description here
10  class TASSO_1986_I230950 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1986_I230950);
15
16
17    /// @name Analysis methods
18    //@{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22
23      // Initialise and register projections
24      declare(Beam(), "Beams");
25      declare(UnstableParticles(), "UFS");
26
27      // Book histograms
28      book(_h_p, 1, 1, 1);
29      book(_h_x, 2, 1, 1);
30
31    }
32
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      // Get beams and average beam momentum
37      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
38      const double meanBeamMom = ( beams.first.p3().mod() +
39                                   beams.second.p3().mod() ) / 2.0;
40      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
41
42      for (const Particle& p : apply<UnstableParticles>(event, "UFS").
43	     particles(Cuts::pid==PID::PI0)) {
44	double modp = p.p3().mod();
45	double xE = p.E()/meanBeamMom;
46	double beta = modp/p.E();
47	_h_p->fill(modp);
48	_h_x->fill(xE  ,1./beta);
49      }
50    }
51
52
53    /// Normalise histograms etc., after the run
54    void finalize() {
55      scale(_h_p, crossSection()/nanobarn/sumOfWeights());
56      scale(_h_x, sqr(sqrtS())*crossSection()/microbarn/sumOfWeights());
57    }
58
59    //@}
60
61
62    /// @name Histograms
63    //@{
64    Histo1DPtr _h_p, _h_x;
65    //@}
66
67
68  };
69
70
71  // The hook for the plugin system
72  RIVET_DECLARE_PLUGIN(TASSO_1986_I230950);
73
74
75}