rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

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
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/Beam.hh"

namespace Rivet {


  /// @brief Add a short analysis description here
  class TASSO_1986_I230950 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(TASSO_1986_I230950);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(Beam(), "Beams");
      declare(UnstableParticles(), "UFS");

      // Book histograms
      book(_h_p, 1, 1, 1);
      book(_h_x, 2, 1, 1);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = ( beams.first.p3().mod() +
                                   beams.second.p3().mod() ) / 2.0;
      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);

      for (const Particle& p : apply<UnstableParticles>(event, "UFS").
	     particles(Cuts::pid==PID::PI0)) {
	double modp = p.p3().mod();
	double xE = p.E()/meanBeamMom;
	double beta = modp/p.E();
	_h_p->fill(modp);
	_h_x->fill(xE  ,1./beta);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_p, crossSection()/nanobarn/sumOfWeights());
      scale(_h_x, sqr(sqrtS())*crossSection()/microbarn/sumOfWeights());
    }

    //@}


    /// @name Histograms
    //@{
    Histo1DPtr _h_p, _h_x;
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(TASSO_1986_I230950);


}