Rivet Analyses Reference

ZEUS_1999_I500267

Measurement of High-$Q^2$ Neutral-Current $e^+p$ Deep Inelastic Scattering Cross-Sections at HERA
Experiment: ZEUS (HERA Run I)
Inspire ID: 500267
Status: VALIDATED
Authors:
  • Andrii Verbytskyi
References:Beams: p+ e+
Beam energies: (820.0, 27.5) GeV
Run details:
  • Inclusive high $Q^2$ DIS

The $e^+p$ neutral-current deep inelastic scattering differential cross-sections $d\sigma/dQ^2$, for $Q^2$ > 400 $GeV^2$, $d\sigma/dx$ and $d\sigma/dy$, for $Q^2$ > 400, 2500 and 10000 $GeV^2$, have been measured with the ZEUS detector at HERA. The data sample of $47.7 pb^{-1}$ was collected at a center-of-mass energy of 300 GeV. The cross-section, $d\sigma/dQ^2$, falls by six orders of magnitude between $Q^2 = 400$ and $40000 GeV^2$. The predictions of the Standard Model are in very good agreement with the data. Complementing the observations of time-like $Z^0$ contributions to fermion-antifermion annihilation, the data provide direct evidence for the presence of $Z^0$ exchange in the space-like region explored by deep inelastic scattering.

Source code: ZEUS_1999_I500267.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

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DISKinematics.hh"


namespace Rivet {

/// @brief  Measurement of High-$Q^2$ Neutral-Current in DIS
class ZEUS_1999_I500267 : public Analysis {

  public:
      /// Constructor
      RIVET_DEFAULT_ANALYSIS_CTOR(ZEUS_1999_I500267);

      /// @name Analysis methods
      ///@{

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

          const DISKinematics& diskin = DISKinematics();
          declare(diskin,"Kinematics");

          book(_h_Q2,   1, 1, 1);
          book(_h_x[0], 2, 1, 1);
          book(_h_x[1], 3, 1, 1);
          book(_h_x[2], 4, 1, 1);

      }

      /// Perform the per-event analysis
      void analyze(const Event& event) {

          /// DIS kinematics
          const DISKinematics& dk = apply<DISKinematics>(event, "Kinematics");

          double q2  = dk.Q2();
          double x   = dk.x();
          double y   = dk.y();

          if (y > 0.95) vetoEvent;
          if (q2 < 400) vetoEvent;
          if (q2 > 400) _h_x[0]->fill(x);
          if (q2 > 2500) _h_x[1]->fill(x);
          if (q2 > 10000) _h_x[2]->fill(x);
          _h_Q2->fill(q2);

      }

      /// Normalise histograms etc., after the run
      void finalize() {
          const double norm = crossSection()/picobarn/sumOfWeights();
          scale(_h_Q2, norm);
          scale(_h_x[0],norm);
          scale(_h_x[1], norm);
          scale(_h_x[2], norm);
      }

    private:

      Histo1DPtr _h_Q2;
      Histo1DPtr _h_x[3];
  };

  // The hook for the plugin system
  RIVET_DECLARE_PLUGIN(ZEUS_1999_I500267);


}

Edit this page on GitLab