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Rivet analyses reference

CDF_2000_S4155203

Z pT measurement in CDF Z -> $e^+e^-$ events
Experiment: CDF (Tevatron Run 1)
Inspire ID: 505738
Status: VALIDATED
Authors:
• Hendrik Hoeth
References:
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 $Z$ $p_\perp$, in a fully-factorised picture, is generated by the momentum balance against initial state radiation (ISR) and the primordial/intrinsic $p_\perp$ of the $Z$'s parent partons in the incoming hadrons. The $Z$ $p_\perp$ 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_S4155203.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 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/ZFinder.hh" namespace Rivet { /// @brief CDF Run I Z \f$p_\perp \f$ in Drell-Yan events /// @author Hendrik Hoeth class CDF_2000_S4155203 : public Analysis { public: /// Constructor CDF_2000_S4155203() : Analysis("CDF_2000_S4155203") { } /// @name Analysis methods //@{ void init() { // Set up projections ZFinder zfinder(FinalState(), Cuts::open(), PID::ELECTRON, 66*GeV, 116*GeV, 0.0, ZFinder::ClusterPhotons::NONE); declare(zfinder, "ZFinder"); // Book histogram book(_hist_zpt ,1, 1, 1); } /// Do the analysis void analyze(const Event& e) { const ZFinder& zfinder = apply(e, "ZFinder"); 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; }; // The hook for the plugin system DECLARE_RIVET_PLUGIN(CDF_2000_S4155203); } `