Rivet analyses reference

CMS_2012_I941555

Measurement of differential $Z/\gamma^*$ $p_T$ and y
Experiment: CMS (LHC)
Inspire ID: 941555
Status: VALIDATED
Authors:

Luca Perrozzi
Justin Hugon

References:

Phys.Rev. D85 (2012) 032002
arXiv: 1110.4973
Public page: CMS-EWK-10-010
CERN-PH-EP-2011-169

Beams: p+ p+
Beam energies: (3500.0, 3500.0) GeV
Run details:

$p p \to \mu^+ \mu^-$ +X 7 TeV. Needs mass cut on lepton pair to avoid photon singularity, restrict $Z/\gamma^*$ mass range to roughly $50 \text{GeV}/c^2 < m_{\mu\mu} < 130 \text{GeV}/c^2$ for efficiency. Result is corrected for QED FSR (i.e. leptons are dressed), so turn off in generator.

Cross section as a function of $p_T$ and y of the Z boson decaying into muons in p p collisions at $\sqrt{s}$ = 7 TeV. $p_T$ and y cross sections are measured for $60 < m_{\mu\mu} < 120$ GeV. The $p_T$ cross section is measured for lepton $p_T > 20$ GeV and $\eta < 2.1$ , while the y cross section is extrapolated to all lepton $p_T$ and $\eta$ . This measurement was performed using 36 pb $^{-1}$ of data collected during 2010 with the CMS detector at the LHC.

Source code: CMS_2012_I941555.cc

  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/DileptonFinder.hh"
  4
  5namespace Rivet {
  6
  7
  8  /// @brief CMS Z pT and rapidity in Drell-Yan events at 7 TeV
  9  ///
 10  /// @author Justin Hugon, Luca Perrozzi
 11  class CMS_2012_I941555 : public Analysis {
 12  public:
 13
 14    /// Constructor
 15    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I941555);
 16
 17
 18    /// @name Analysis methods
 19    /// @{
 20
 21    void init() {
 22
 23      // Set up projections
 24      /// @todo Really?: was DileptonFinder zfinder_dressed_mu_pt(-2.1, 2.1, 20, PID::MUON, 60*GeV, 120*GeV, 0.2, false, true);
 25      Cut cuts = Cuts::abseta < 2.1 && Cuts::pT > 20*GeV;
 26      DileptonFinder zfinder_dressed_mu_pt(91.2*GeV, 0.2, cuts && Cuts::abspid == PID::MUON, Cuts::massIn(60*GeV, 120*GeV));
 27      declare(zfinder_dressed_mu_pt, "DileptonFinder_dressed_mu_pt");
 28      DileptonFinder zfinder_dressed_el_pt(91.2*GeV, 0.1, cuts && Cuts::abspid == PID::ELECTRON, Cuts::massIn(60*GeV, 120*GeV));
 29      declare(zfinder_dressed_el_pt, "DileptonFinder_dressed_el_pt");
 30
 31      DileptonFinder zfinder_dressed_mu_rap(91.2*GeV, 0.1, Cuts::abspid == PID::MUON, Cuts::massIn(60*GeV, 120*GeV));
 32      declare(zfinder_dressed_mu_rap, "DileptonFinder_dressed_mu_rap");
 33      DileptonFinder zfinder_dressed_el_rap(91.2*GeV, 0.1, Cuts::abspid == PID::ELECTRON, Cuts::massIn(60*GeV, 120*GeV));
 34      declare(zfinder_dressed_el_rap, "DileptonFinder_dressed_el_rap");
 35
 36      // Book histograms
 37      book(_hist_zrap_mu_dressed      , 1, 1, 1);  // muon "dressed" rapidity
 38      book(_hist_zrap_el_dressed      , 1, 1, 2);  // electron "dressed" rapidity
 39      book(_hist_zrap_comb_dressed    , 1, 1, 3);  // electron "dressed" rapidity
 40
 41      book(_hist_zpt_mu_dressed       , 2, 1, 1);  // muon "dressed" pt
 42      book(_hist_zpt_el_dressed       , 2, 1, 2);  // electron "dressed" pt
 43      book(_hist_zpt_comb_dressed     , 2, 1, 3);  // electron "dressed" pt
 44
 45      book(_hist_zptpeak_mu_dressed   , 3, 1, 1);  // muon "dressed" pt peak
 46      book(_hist_zptpeak_el_dressed   , 3, 1, 2);  // electron "dressed" pt peak
 47      book(_hist_zptpeak_comb_dressed , 3, 1, 3);  // electron "dressed" pt peak
 48    }
 49
 50
 51    /// Do the analysis
 52    void analyze(const Event& evt) {
 53
 54      const DileptonFinder& zfinder_dressed_mu_rap = apply<DileptonFinder>(evt, "DileptonFinder_dressed_mu_rap");
 55      if (!zfinder_dressed_mu_rap.bosons().empty()) {
 56        const FourMomentum pZ = zfinder_dressed_mu_rap.bosons()[0].momentum();
 57        _hist_zrap_mu_dressed->fill(pZ.absrapidity());
 58        _hist_zrap_comb_dressed->fill(pZ.absrapidity());
 59      }
 60
 61      const DileptonFinder& zfinder_dressed_mu_pt = apply<DileptonFinder>(evt, "DileptonFinder_dressed_mu_pt");
 62      if (!zfinder_dressed_mu_pt.bosons().empty()) {
 63        const FourMomentum pZ = zfinder_dressed_mu_pt.bosons()[0].momentum();
 64        _hist_zpt_mu_dressed->fill(pZ.pT()/GeV);
 65        _hist_zpt_comb_dressed->fill(pZ.pT()/GeV);
 66        if (pZ.pT() < 30*GeV) {
 67          _hist_zptpeak_mu_dressed->fill(pZ.pT()/GeV);
 68          _hist_zptpeak_comb_dressed->fill(pZ.pT()/GeV);
 69        }
 70      }
 71
 72      const DileptonFinder& zfinder_dressed_el_rap = apply<DileptonFinder>(evt, "DileptonFinder_dressed_el_rap");
 73      if (!zfinder_dressed_el_rap.bosons().empty()) {
 74        const FourMomentum pZ = zfinder_dressed_el_rap.bosons()[0].momentum();
 75        _hist_zrap_el_dressed->fill(abs(pZ.rapidity()/GeV));
 76        _hist_zrap_comb_dressed->fill(abs(pZ.rapidity()/GeV));
 77      }
 78
 79      const DileptonFinder& zfinder_dressed_el_pt = apply<DileptonFinder>(evt, "DileptonFinder_dressed_el_pt");
 80      if (!zfinder_dressed_el_pt.bosons().empty()) {
 81        const FourMomentum pZ = zfinder_dressed_el_pt.bosons()[0].momentum();
 82        _hist_zpt_el_dressed->fill(pZ.pT()/GeV);
 83        _hist_zpt_comb_dressed->fill(pZ.pT()/GeV);
 84        if (pZ.pT() < 30*GeV) {
 85          _hist_zptpeak_el_dressed->fill(pZ.pT()/GeV);
 86          _hist_zptpeak_comb_dressed->fill(pZ.pT()/GeV);
 87        }
 88      }
 89
 90    }
 91
 92
 93    void finalize() {
 94      normalize(_hist_zrap_mu_dressed);
 95      normalize(_hist_zpt_mu_dressed);
 96      normalize(_hist_zptpeak_mu_dressed);
 97
 98      normalize(_hist_zrap_el_dressed);
 99      normalize(_hist_zpt_el_dressed);
100      normalize(_hist_zptpeak_el_dressed);
101
102      normalize(_hist_zrap_comb_dressed);
103      normalize(_hist_zpt_comb_dressed);
104      normalize(_hist_zptpeak_comb_dressed);
105    }
106
107    /// @}
108
109
110  private:
111
112    Histo1DPtr _hist_zrap_mu_dressed;
113    Histo1DPtr _hist_zpt_mu_dressed;
114    Histo1DPtr _hist_zptpeak_mu_dressed;
115
116    Histo1DPtr _hist_zrap_el_dressed;
117    Histo1DPtr _hist_zpt_el_dressed;
118    Histo1DPtr _hist_zptpeak_el_dressed;
119
120    Histo1DPtr _hist_zrap_comb_dressed;
121    Histo1DPtr _hist_zpt_comb_dressed;
122    Histo1DPtr _hist_zptpeak_comb_dressed;
123
124  };
125
126
127  RIVET_DECLARE_PLUGIN(CMS_2012_I941555);
128
129}