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CDF_2009_I856131

Z rapidity measurement
Experiment: CDF (Tevatron Run 2)
Inspire ID: 856131
Status: VALIDATED
Authors:
  • Frank Siegert
References: Beams: p- p+
Beam energies: (980.0, 980.0) GeV
Run details:
  • $p \bar{p} \to e^+ e^-$ + jets at 1960 GeV. Needs mass cut on lepton pair to avoid photon singularity, looser than $66 < m_{ee} < 116$ GeV

CDF measurement of the total cross section and rapidity distribution, $\mathrm{d}\sigma/\mathrm{d}y$, for $q\bar{q}\to \gamma^{*}/Z\to e^{+}e^{-}$ events in the $Z$ boson mass region ($66<M_{ee}<116$ GeV/c$^2$) produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV with 2.1 fb$^{-1}$ of integrated luminosity.

Source code: CDF_2009_I856131.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ZFinder.hh"

namespace Rivet {


  /// @brief CDF Z boson rapidity measurement
  class CDF_2009_I856131 : public Analysis {
  public:

    /// @name Constructors etc.
    //@{

    /// Constructor
    CDF_2009_I856131()
      : Analysis("CDF_2009_I856131")
    {    }

    //@}


  public:

    /// @name Analysis methods
    //@{

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

      /// Initialise and register projections here
      // this seems to have been corrected completely for all selection cuts,
      // i.e. eta cuts and pT cuts on leptons.
      ZFinder zfinder(FinalState(), Cuts::open(), PID::ELECTRON,
                      66*GeV, 116*GeV, 0.2, ZFinder::CLUSTERNODECAY, ZFinder::TRACK);
      declare(zfinder, "ZFinder");


      /// Book histograms here
      _h_xs = bookHisto1D(1, 1, 1);
      _h_yZ = bookHisto1D(2, 1, 1);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const ZFinder& zfinder = apply<ZFinder>(event, "ZFinder");
      if (zfinder.bosons().size() == 1) {
        const double weight = event.weight();
        _h_yZ->fill(fabs(zfinder.bosons()[0].rapidity()), weight);
        _h_xs->fill(1960, weight);
      } else {
        MSG_DEBUG("no unique lepton pair found.");
      }

    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_xs, crossSection()/sumOfWeights());
      // Data seems to have been normalized for the avg of the two sides
      // (+ve & -ve rapidity) rather than the sum, hence the 0.5:
      scale(_h_yZ, 0.5*crossSection()/sumOfWeights());
    }

    //@}


  private:

    /// @name Histograms
    //@{
    Histo1DPtr _h_yZ;
    Histo1DPtr _h_xs;
    //@}

  };



  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(CDF_2009_I856131);

}