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L3_1994_I374698

$\pi^0$ and $\eta$ spectra at 91 GeV
Experiment: L3 ()
Inspire ID: 374698
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett.B 328 (1994) 223-233
Beams: e+ e-
Beam energies: (45.6, 45.6) GeV
Run details:
  • e+e- -> hadrons

Measurement of the momentum distribution of the $\pi^0$ and $\eta$ mesons at 91.2 GeV in $e^+e^-$ collisions by the L3 collaboration.

Source code: L3_1994_I374698.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief pi0 and eta spectra at 91 GeV
 9  class L3_1994_I374698 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(L3_1994_I374698);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // projections
22      declare(UnstableParticles(), "UFS");
23      // book histos
24      book(_h_pi0_x_P , 5,1,1);
25      book(_h_pi0_x_H , 6,1,1);
26      book(_h_pi0_xi  , 7,1,1);
27      book(_h_eta_x_P , 8,1,1);
28      book(_h_eta_x_H , 9,1,1);
29      book(_h_eta_xi  ,10,1,1);
30    }
31
32
33    /// Perform the per-event analysis
34    void analyze(const Event& event) {
35      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
36      for (const Particle & p : ufs.particles(Cuts::pid==PID::PI0 ||
37					      Cuts::pid==PID::ETA)) {
38        const double x = 2.*p.momentum().p3().mod()/sqrtS();
39	if(p.pid()==PID::PI0) {
40	  _h_pi0_x_P->fill(x);
41	  _h_pi0_x_H->fill(x);
42	  _h_pi0_xi->fill(-log(x));
43	}
44	else {
45	  _h_eta_x_P->fill(x);
46	  _h_eta_x_H->fill(x);
47	  _h_eta_xi->fill(-log(x));
48	}
49      }
50    }
51
52
53    /// Normalise histograms etc., after the run
54    void finalize() {
55      scale(_h_pi0_x_P   , 1./sumOfWeights());
56      scale(_h_pi0_x_H   , 1./sumOfWeights());
57      scale(_h_pi0_xi    , 1./sumOfWeights());
58      scale(_h_eta_x_P   , 1./sumOfWeights());
59      scale(_h_eta_x_H   , 1./sumOfWeights());
60      scale(_h_eta_xi    , 1./sumOfWeights());
61    }
62
63    /// @}
64
65
66    /// @name Histograms
67    /// @{
68    Histo1DPtr _h_pi0_x_P,_h_pi0_x_H,_h_pi0_xi;
69    Histo1DPtr _h_eta_x_P,_h_eta_x_H,_h_eta_xi;
70    /// @}
71
72
73  };
74
75
76  RIVET_DECLARE_PLUGIN(L3_1994_I374698);
77
78}