Rivet analyses

title: CDF_2000_I505738

Z pT measurement in CDF Z -> $e^+e^-$ events

Experiment: CDF (Tevatron Run 1)

Inspire ID: 505738

Status: VALIDATED

Authors: - Hendrik Hoeth

References: - Phys.Rev.Lett.84:845-850,2000 - arXiv: hep-ex/0001021 - DOI: 10.1103/PhysRevLett.84.845

Beams: p- p+

Beam energies: (900.0, 900.0)GeV

Run details: - $p\bar{p}$ collisions at 1800 GeV. $Z/\gamma^$ Drell-Yan events with $e^+e^-$ decay mode only. Restrict $Z/\gamma^$ mass range to roughly $50~\text{GeV}/c^2 < m_{ee} < 120~\text{GeV}/c^2$ for efficiency.

Measurement of transverse momentum and total cross section of $e^+e^-$ pairs in the Z-boson region of $66~\text{GeV}/c^2 < m_{ee} < 116~\text{GeV}/c^2$ from pbar-p collisions at $\sqrt{s} = 1.8$ TeV, with the Tevatron CDF detector. The $Z$ $\pT$, in a fully-factorised picture, is generated by the momentum balance against initial state radiation (ISR) and the primordial/intrinsic $\pT$ of the $Z$'s parent partons in the incoming hadrons. The $Z$ $\pT$ is important in generator tuning to fix the interplay of ISR and multi-parton interactions (MPI) in generating `underlying event' activity. This analysis is subject to ambiguities in the experimental Z pT definition, since the Rivet implementation reconstructs the Z momentum from the dilepton pair with finite cones for QED bremstrahlung summation, rather than non-portable direct use of the (sometimes absent) Z in the event record.

Source code:CDF_2000_I505738.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/DileptonFinder.hh"

namespace Rivet {

/// @brief CDF Run I Z \f$ p_\perp \f$ in Drell-Yan events /// /// @author Hendrik Hoeth class CDF_2000_I505738 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CDF_2000_I505738);


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

void init() {
  // Set up projections
  DileptonFinder zfinder(91.2 * GeV, 0.0, Cuts::abspid == PID::ELECTRON,
                         Cuts::massIn(66 * GeV, 116 * GeV));
  declare(zfinder, "DileptonFinder");

  // Book histogram
  book(_hist_zpt, 1, 1, 1);
}


/// Do the analysis
void analyze(const Event& e) {
  const DileptonFinder& zfinder = apply<DileptonFinder>(e, "DileptonFinder");
  if (zfinder.bosons().size() != 1) {
    MSG_DEBUG("Num e+ e- pairs found = " << zfinder.bosons().size());
    vetoEvent;
  }

  FourMomentum pZ = zfinder.bosons()[0].momentum();
  if (pZ.mass2() < 0) {
    MSG_DEBUG("Negative Z mass**2 = " << pZ.mass2() / GeV2 << "!");
    vetoEvent;
  }

  MSG_DEBUG("Dilepton mass = " << pZ.mass() / GeV << " GeV");
  MSG_DEBUG("Dilepton pT   = " << pZ.pT() / GeV << " GeV");
  _hist_zpt->fill(pZ.pT() / GeV);
}


void finalize() {
  scale(_hist_zpt, crossSection() / picobarn / sumOfWeights());
}

/// @}

private:

Histo1DPtr _hist_zpt;

};

RIVET_DECLARE_ALIASED_PLUGIN(CDF_2000_I505738, CDF_2000_S4155203);

} ```

Aliases: - CDF_2000_S4155203