Rivet analyses referenceCDF_2000_I505738Z pT measurement in CDF Z -> $e^+e^-$ eventsExperiment: CDF (Tevatron Run 1) Inspire ID: 505738 Status: VALIDATED Authors:
Beam energies: (900.0, 900.0) GeV Run details:
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_I505738.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/DileptonFinder.hh"
4
5namespace Rivet {
6
7
8 /// @brief CDF Run I Z \f$ p_\perp \f$ in Drell-Yan events
9 ///
10 /// @author Hendrik Hoeth
11 class CDF_2000_I505738 : public Analysis {
12 public:
13
14 RIVET_DEFAULT_ANALYSIS_CTOR(CDF_2000_I505738);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 void init() {
21 // Set up projections
22 DileptonFinder zfinder(91.2*GeV, 0.0, Cuts::abspid == PID::ELECTRON, Cuts::massIn(66*GeV, 116*GeV));
23 declare(zfinder, "DileptonFinder");
24
25 // Book histogram
26 book(_hist_zpt ,1, 1, 1);
27 }
28
29
30 /// Do the analysis
31 void analyze(const Event& e) {
32 const DileptonFinder& zfinder = apply<DileptonFinder>(e, "DileptonFinder");
33 if (zfinder.bosons().size() != 1) {
34 MSG_DEBUG("Num e+ e- pairs found = " << zfinder.bosons().size());
35 vetoEvent;
36 }
37
38 FourMomentum pZ = zfinder.bosons()[0].momentum();
39 if (pZ.mass2() < 0) {
40 MSG_DEBUG("Negative Z mass**2 = " << pZ.mass2()/GeV2 << "!");
41 vetoEvent;
42 }
43
44 MSG_DEBUG("Dilepton mass = " << pZ.mass()/GeV << " GeV");
45 MSG_DEBUG("Dilepton pT = " << pZ.pT()/GeV << " GeV");
46 _hist_zpt->fill(pZ.pT()/GeV);
47 }
48
49
50 void finalize() {
51 scale(_hist_zpt, crossSection()/picobarn/sumOfWeights());
52 }
53
54 /// @}
55
56
57 private:
58
59 Histo1DPtr _hist_zpt;
60
61 };
62
63
64
65 RIVET_DECLARE_ALIASED_PLUGIN(CDF_2000_I505738, CDF_2000_S4155203);
66
67}
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