Rivet analyses
title: ATLAS_2013_I1190187
Measurement of the $W^+ W^-$ production cross-section at 7 TeV
Experiment: ATLAS (LHC)
Inspire ID: 1190187
Status: VALIDATED
Authors: - Oldrich Kepka - Katerina Moudra
References: - arXiv: 1210.2979
Beams: p+ p+
Beam energies: (3500.0, 3500.0)GeV
Run details: - Run with inclusive $W^+ W^-$ events, with $W$ decays to electron + MET, muon + MET, or tau + MET.
Measurement of the fiducial cross section for $W^+ W^-$ production in proton proton collisions at a centre-of mass energy of 7 TeV, is presented, using data corresponding to an integrated luminosity of 4.6/fb collected by the ATLAS experiment at the Large Hadron Collider. The cross section is measured in the leptonic decay channels, using electron+MET and muon+MET $W$ decays. $W \to \tau$ processes with the tau decaying into electron + MET or muon + MET are also included in the measurement. The fiducial region contains dressed leptons in restricted $p_T$ and $\eta$ ranges. The selection has specific requirements for each production channel. A measurement of the normalized fiducial cross section as a function of the leading lepton transverse momentum is also presented.
Source code:ATLAS_2013_I1190187.cc
```c++ // -- C++ --
include "Rivet/Analysis.hh"
include "Rivet/Projections/FastJets.hh"
include "Rivet/Projections/FinalState.hh"
include "Rivet/Projections/IdentifiedFinalState.hh"
include "Rivet/Projections/LeptonFinder.hh"
include "Rivet/Projections/MissingMomentum.hh"
include "Rivet/Projections/VetoedFinalState.hh"
namespace Rivet {
/// ATLAS Wee Wemu Wmumu analysis at Z TeV class ATLAS_2013_I1190187 : public Analysis { public:
/// Default constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2013_I1190187);
void init() {
Cut etaRanges_EL = (Cuts::abseta < 1.37 || Cuts::absetaIn(1.52, 2.47)) && Cuts::pT > 20 * GeV;
Cut etaRanges_MU = Cuts::abseta < 2.4 && Cuts::pT > 20 * GeV;
declare(MissingMomentum(), "MET");
IdentifiedFinalState neutrinoFS;
neutrinoFS.acceptNeutrinos();
declare(neutrinoFS, "Neutrinos");
////////////////////////////////////////////////////////
// DRESSED LEPTONS
// 3.arg: 0.1 = dR(lep,phot)
// 4.arg: true = do clustering
// 7.arg: false = ignore photons from hadron or tau
//
//////////////////////////////////////////////////////////
LeptonFinder electronFS(0.1, Cuts::abspid == PID::ELECTRON && etaRanges_EL);
declare(electronFS, "ELECTRON_FS");
LeptonFinder muonFS(0.1, Cuts::abspid == PID::MUON && etaRanges_MU);
declare(muonFS, "MUON_FS");
VetoedFinalState jetinput;
jetinput.addVetoOnThisFinalState(neutrinoFS);
FastJets jetpro(jetinput, JetAlg::ANTIKT, 0.4, JetMuons::NONE);
declare(jetpro, "jet");
// Book histograms
book(_h_Wl1_pT_mumu, 1, 1, 2);
book(_h_Wl1_pT_ee, 1, 1, 1);
book(_h_Wl1_pT_emu, 1, 1, 3);
book(_h_Wl1_pT_inclusive, 4, 1, 1);
}
/// Do the analysis
void analyze(const Event& e) {
const DressedLeptons& muonFS = apply<LeptonFinder>(e, "MUON_FS").dressedLeptons();
const DressedLeptons& electronFS = apply<LeptonFinder>(e, "ELECTRON_FS").dressedLeptons();
const MissingMomentum& met = apply<MissingMomentum>(e, "MET");
DressedLeptons dressed_lepton, isolated_lepton, fiducial_lepton;
dressed_lepton.insert(dressed_lepton.end(), muonFS.begin(), muonFS.end());
dressed_lepton.insert(dressed_lepton.end(), electronFS.begin(), electronFS.end());
////////////////////////////////////////////////////////////////////////////
// OVERLAP REMOVAL
// -electrons with dR(e,mu)<0.1 are removed
// -lower pT electrons with dR(e,e)<0.1 are removed
//
////////////////////////////////////////////////////////////////////////////
for (DressedLepton& l1 : dressed_lepton) {
bool l_isolated = true;
for (DressedLepton& l2 : dressed_lepton) {
if (!isSame(l1, l2) && l2.bareLepton().abspid() == PID::ELECTRON) {
double overlapControl_ll = deltaR(l1.bareLepton(), l2.bareLepton());
if (overlapControl_ll < 0.1) {
l_isolated = false;
// e/e overlap removal
if (l1.bareLepton().abspid() == PID::ELECTRON) {
if (l1.bareLepton().pT() > l2.bareLepton().pT()) {
isolated_lepton.push_back(l1); //keep e with highest pT
}
else {
isolated_lepton.push_back(l2); //keep e with highest pT
}
}
// e/mu overlap removal
if (l1.bareLepton().abspid() == PID::MUON) isolated_lepton.push_back(l1); //keep mu
}
}
}
if (l_isolated) isolated_lepton.push_back(l1);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////
// PRESELECTION:
// "isolated_lepton:"
// * electron: pt>20 GeV, |eta|<1.37, 1.52<|eta|<2.47, dR(electron,muon)>0.1
// * muon: pt>20 GeV, |eta|<2.4
// * dR(l,l)>0.1
//
// "fiducial_lepton"= isolated_lepton with
// * 2 leptons (e or mu)
// * leading lepton pt (pT_l1) >25 GeV
// * opposite charged leptons
//
///////////////////////////////////////////////////////////////////////////////////////////////////////////
if (isolated_lepton.size() != 2) vetoEvent;
sort(isolated_lepton.begin(), isolated_lepton.end(), cmpMomByPt);
if (isolated_lepton[0].pT() > 25 * GeV && charge3(isolated_lepton[0]) != charge3(isolated_lepton[1])) {
fiducial_lepton.insert(fiducial_lepton.end(), isolated_lepton.begin(), isolated_lepton.end());
}
if (fiducial_lepton.size() == 0) vetoEvent;
double pT_l1 = fiducial_lepton[0].pT();
double M_l1l2 = (fiducial_lepton[0].momentum() + fiducial_lepton[1].momentum()).mass();
double pT_l1l2 = (fiducial_lepton[0].momentum() + fiducial_lepton[1].momentum()).pT();
/////////////////////////////////////////////////////////////////////////
// JETS
// -"alljets": found by "jetpro" projection && pT()>25 GeV && |y|<4.5
// -"vetojets": "alljets" && dR(electron,jet)>0.3
//
/////////////////////////////////////////////////////////////////////////
Jets alljets, vetojets;
for (const Jet& j : apply<FastJets>(e, "jet").jetsByPt(Cuts::pT > 25 && Cuts::absrap < 4.5)) {
alljets.push_back(j);
bool deltaRcontrol = true;
for (DressedLepton& fl : fiducial_lepton) {
if (fl.bareLepton().abspid() == PID::ELECTRON) { //electrons
double deltaRjets = deltaR(fl.bareLepton().momentum(), j.momentum(), RAPIDITY);
if (deltaRjets <= 0.3)
deltaRcontrol = false; //false if at least one electron is in the overlap region
}
}
if (deltaRcontrol) vetojets.push_back(j);
}
/////////////////////////////////////////////////////////////////////////////////////////////////
// MISSING ETrel
// -"mismom": fourvector of invisible momentum found by "met" projection
// -"delta_phi": delta phi between mismom and the nearest "fiducial_lepton" or "vetojet"
// -"MET_rel": missing transverse energy defined as:
// *"mismom" for "delta_phi" >= (0.5*pi)
// *"mismom.pT()*sin(delta_phi)" for "delta_phi" < (0.5*pi)
//
/////////////////////////////////////////////////////////////////////////////////////////////////
FourMomentum mismom;
double MET_rel = 0, delta_phi = 0;
mismom = -met.visibleMomentum();
vector<double> vL_MET_angle, vJet_MET_angle;
vL_MET_angle.push_back(fabs(deltaPhi(fiducial_lepton[0].momentum(), mismom)));
vL_MET_angle.push_back(fabs(deltaPhi(fiducial_lepton[1].momentum(), mismom)));
for (double& lM : vL_MET_angle)
if (lM > M_PI) lM = 2 * M_PI - lM;
std::sort(vL_MET_angle.begin(), vL_MET_angle.end());
if (vetojets.size() == 0) delta_phi = vL_MET_angle[0];
if (vetojets.size() > 0) {
for (Jet& vj : vetojets) {
double jet_MET_angle = fabs(deltaPhi(vj.momentum(), mismom));
if (jet_MET_angle > M_PI) jet_MET_angle = 2 * M_PI - jet_MET_angle;
vJet_MET_angle.push_back(jet_MET_angle);
}
std::sort(vJet_MET_angle.begin(), vJet_MET_angle.end());
if (vL_MET_angle[0] <= vJet_MET_angle[0]) delta_phi = vL_MET_angle[0];
if (vL_MET_angle[0] > vJet_MET_angle[0]) delta_phi = vJet_MET_angle[0];
}
if (delta_phi >= (0.5 * M_PI)) delta_phi = 0.5 * M_PI;
MET_rel = mismom.pT() * sin(delta_phi);
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// CUTS
// -jetveto: event with at least one vetojet is vetoed
// -M_Z: Z mass M_Z=91.1876*GeV
//
// * ee channel: MET_rel > 45 GeV, M_l1l2 > 15 GeV, |M_l1l2-M_Z| > 15 GeV, jetveto, pT_l1l2 > 30 GeV
// * mumu channel: MET_rel > 45 GeV, M_l1l2 > 15 GeV, |M_l1l2-M_Z| > 15 GeV, jetveto, pT_l1l2 > 30 GeV
// * emu channel: MET_rel > 25 GeV, M_l1l2 > 10 GeV, |M_l1l2-M_Z| > 0 GeV, jetveto, pT_l1l2 > 30 GeV
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// ee channel
if (fiducial_lepton[0].abspid() == PID::ELECTRON && fiducial_lepton[1].abspid() == PID::ELECTRON) {
if (MET_rel <= 45 * GeV) vetoEvent;
if (M_l1l2 <= 15 * GeV) vetoEvent;
if (fabs(M_l1l2 - 91.1876 * GeV) <= 15 * GeV) vetoEvent;
if (vetojets.size() != 0) vetoEvent;
if (pT_l1l2 <= 30 * GeV) vetoEvent;
_h_Wl1_pT_ee->fill(7000);
_h_Wl1_pT_inclusive->fill(pT_l1);
}
// mumu channel
else if (fiducial_lepton[0].abspid() == PID::MUON && fiducial_lepton[1].abspid() == PID::MUON) {
if (MET_rel <= 45 * GeV) vetoEvent;
if (M_l1l2 <= 15 * GeV) vetoEvent;
if (fabs(M_l1l2 - 91.1876 * GeV) <= 15 * GeV) vetoEvent;
if (vetojets.size() != 0) vetoEvent;
if (pT_l1l2 <= 30 * GeV) vetoEvent;
_h_Wl1_pT_mumu->fill(7000);
_h_Wl1_pT_inclusive->fill(pT_l1);
}
// emu channel
else if (fiducial_lepton[0].abspid() != fiducial_lepton[1].abspid()) {
if (MET_rel <= 25 * GeV) vetoEvent;
if (M_l1l2 <= 10 * GeV) vetoEvent;
if (vetojets.size() != 0) vetoEvent;
if (pT_l1l2 <= 30 * GeV) vetoEvent;
_h_Wl1_pT_emu->fill(7000);
_h_Wl1_pT_inclusive->fill(pT_l1);
}
}
/// Finalize
void finalize() {
const double norm = crossSection() / sumOfWeights() / femtobarn;
scale(_h_Wl1_pT_ee, norm);
scale(_h_Wl1_pT_mumu, norm);
scale(_h_Wl1_pT_emu, norm);
normalize(_h_Wl1_pT_inclusive, 1);
}
private:
BinnedHistoPtr<int> _h_Wl1_pT_ee, _h_Wl1_pT_mumu, _h_Wl1_pT_emu;
Histo1DPtr _h_Wl1_pT_inclusive;
};
RIVET_DECLARE_PLUGIN(ATLAS_2013_I1190187);
} ```