Rivet analyses
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 - Expt 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
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DileptonFinder.hh"
namespace Rivet {
/// @brief CMS Z pT and rapidity in Drell-Yan events at 7 TeV
///
/// @author Justin Hugon, Luca Perrozzi
class CMS_2012_I941555 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I941555);
/// @name Analysis methods
/// @{
void init() {
// Set up projections
/// @todo Really?: was DileptonFinder zfinder_dressed_mu_pt(-2.1, 2.1, 20, PID::MUON, 60*GeV, 120*GeV, 0.2, false, true);
Cut cuts = Cuts::abseta < 2.1 && Cuts::pT > 20 * GeV;
DileptonFinder zfinder_dressed_mu_pt(91.2 * GeV, 0.2, cuts && Cuts::abspid == PID::MUON,
Cuts::massIn(60 * GeV, 120 * GeV));
declare(zfinder_dressed_mu_pt, "DileptonFinder_dressed_mu_pt");
DileptonFinder zfinder_dressed_el_pt(91.2 * GeV, 0.1, cuts && Cuts::abspid == PID::ELECTRON,
Cuts::massIn(60 * GeV, 120 * GeV));
declare(zfinder_dressed_el_pt, "DileptonFinder_dressed_el_pt");
DileptonFinder zfinder_dressed_mu_rap(91.2 * GeV, 0.1, Cuts::abspid == PID::MUON,
Cuts::massIn(60 * GeV, 120 * GeV));
declare(zfinder_dressed_mu_rap, "DileptonFinder_dressed_mu_rap");
DileptonFinder zfinder_dressed_el_rap(91.2 * GeV, 0.1, Cuts::abspid == PID::ELECTRON,
Cuts::massIn(60 * GeV, 120 * GeV));
declare(zfinder_dressed_el_rap, "DileptonFinder_dressed_el_rap");
// Book histograms
book(_hist_zrap_mu_dressed, 1, 1, 1); // muon "dressed" rapidity
book(_hist_zrap_el_dressed, 1, 1, 2); // electron "dressed" rapidity
book(_hist_zrap_comb_dressed, 1, 1, 3); // electron "dressed" rapidity
book(_hist_zpt_mu_dressed, 2, 1, 1); // muon "dressed" pt
book(_hist_zpt_el_dressed, 2, 1, 2); // electron "dressed" pt
book(_hist_zpt_comb_dressed, 2, 1, 3); // electron "dressed" pt
book(_hist_zptpeak_mu_dressed, 3, 1, 1); // muon "dressed" pt peak
book(_hist_zptpeak_el_dressed, 3, 1, 2); // electron "dressed" pt peak
book(_hist_zptpeak_comb_dressed, 3, 1, 3); // electron "dressed" pt peak
}
/// Do the analysis
void analyze(const Event& evt) {
const DileptonFinder& zfinder_dressed_mu_rap = apply<DileptonFinder>(evt,
"DileptonFinder_dressed_mu_rap");
if (!zfinder_dressed_mu_rap.bosons().empty()) {
const FourMomentum pZ = zfinder_dressed_mu_rap.bosons()[0].momentum();
_hist_zrap_mu_dressed->fill(pZ.absrapidity());
_hist_zrap_comb_dressed->fill(pZ.absrapidity());
}
const DileptonFinder& zfinder_dressed_mu_pt = apply<DileptonFinder>(evt,
"DileptonFinder_dressed_mu_pt");
if (!zfinder_dressed_mu_pt.bosons().empty()) {
const FourMomentum pZ = zfinder_dressed_mu_pt.bosons()[0].momentum();
_hist_zpt_mu_dressed->fill(pZ.pT() / GeV);
_hist_zpt_comb_dressed->fill(pZ.pT() / GeV);
if (pZ.pT() < 30 * GeV) {
_hist_zptpeak_mu_dressed->fill(pZ.pT() / GeV);
_hist_zptpeak_comb_dressed->fill(pZ.pT() / GeV);
}
}
const DileptonFinder& zfinder_dressed_el_rap = apply<DileptonFinder>(evt,
"DileptonFinder_dressed_el_rap");
if (!zfinder_dressed_el_rap.bosons().empty()) {
const FourMomentum pZ = zfinder_dressed_el_rap.bosons()[0].momentum();
_hist_zrap_el_dressed->fill(abs(pZ.rapidity() / GeV));
_hist_zrap_comb_dressed->fill(abs(pZ.rapidity() / GeV));
}
const DileptonFinder& zfinder_dressed_el_pt = apply<DileptonFinder>(evt,
"DileptonFinder_dressed_el_pt");
if (!zfinder_dressed_el_pt.bosons().empty()) {
const FourMomentum pZ = zfinder_dressed_el_pt.bosons()[0].momentum();
_hist_zpt_el_dressed->fill(pZ.pT() / GeV);
_hist_zpt_comb_dressed->fill(pZ.pT() / GeV);
if (pZ.pT() < 30 * GeV) {
_hist_zptpeak_el_dressed->fill(pZ.pT() / GeV);
_hist_zptpeak_comb_dressed->fill(pZ.pT() / GeV);
}
}
}
void finalize() {
normalize(_hist_zrap_mu_dressed);
normalize(_hist_zpt_mu_dressed);
normalize(_hist_zptpeak_mu_dressed);
normalize(_hist_zrap_el_dressed);
normalize(_hist_zpt_el_dressed);
normalize(_hist_zptpeak_el_dressed);
normalize(_hist_zrap_comb_dressed);
normalize(_hist_zpt_comb_dressed);
normalize(_hist_zptpeak_comb_dressed);
}
/// @}
private:
Histo1DPtr _hist_zrap_mu_dressed;
Histo1DPtr _hist_zpt_mu_dressed;
Histo1DPtr _hist_zptpeak_mu_dressed;
Histo1DPtr _hist_zrap_el_dressed;
Histo1DPtr _hist_zpt_el_dressed;
Histo1DPtr _hist_zptpeak_el_dressed;
Histo1DPtr _hist_zrap_comb_dressed;
Histo1DPtr _hist_zpt_comb_dressed;
Histo1DPtr _hist_zptpeak_comb_dressed;
};
RIVET_DECLARE_PLUGIN(CMS_2012_I941555);
}