Rivet analyses
WWW production at 8 TeV
Experiment: ATLAS (LHC)
Inspire ID: 1492320
Status: VALIDATED
Authors: - Alex Long - Ismet Siral - Louis Helary - Christian Gutschow
References: - Expt page: ATLAS-STDM-2015-07 - arXiv: 1610.05088
Beams: p+ p+
Beam energies: (4000.0, 4000.0)GeV
Run details: - pp -> WWW production at 8 TeV
This paper reports a search for triboson W±W±W∓ production in two decay channels (W±W±W∓ → ℓ±νℓ±νℓ∓ν) and (W±W±W∓ → ℓ±νℓ±νjj with ℓ = e, μ) in proton-proton collision data corresponding to an integrated luminosity of 20.3 fb−1 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the Large Hadron Collider. Events with exactly three charged leptons, or two leptons with the same electric charge in association with two jets, are selected. The total number of events observed in data is consistent with the Standard Model (SM) predictions. The observed 95 % confidence level upper limit on the SM W±W±W∓ production cross section is found to be 730 fb with an expected limit of 560 fb in the absence of SM W±W±W∓ production. Limits are also set on WWWW anomalous quartic gauge couplings. Default will make both plots. Use options 2L2J or 3J to make just one.
Source
code:ATLAS_2016_I1492320.cc
// -*- C++ -*
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/HeavyHadrons.hh"
#include "Rivet/Projections/LeptonFinder.hh"
#include "Rivet/Projections/MissingMomentum.hh"
#include "Rivet/Projections/PromptFinalState.hh"
#include "Rivet/Projections/VetoedFinalState.hh"
namespace Rivet {
/// @brief WWW cross-section at 8 TeV, 3L mode
class ATLAS_2016_I1492320 : public Analysis {
public:
// Default constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2016_I1492320);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Get options from the new option system
_mode = 0;
if (getOption("LMODE") == "3L") _mode = 1;
if (getOption("LMODE") == "2L2J") _mode = 2;
// Charged leptons within acceptance
const PromptFinalState chLep_fid = PromptFinalState(Cuts::abspid == PID::ELECTRON
|| Cuts::abspid == PID::MUON);
const PromptFinalState photon_fs = PromptFinalState(Cuts::abspid == PID::PHOTON);
const LeptonFinder dressed_leps(chLep_fid, photon_fs, 0.1, Cuts::pT > 20 * GeV && Cuts::abseta < 2.5);
declare(dressed_leps, "LeptonFinder");
const LeptonFinder dressed_leps2(chLep_fid, photon_fs, 0.1, Cuts::pT > 10 * GeV);
declare(dressed_leps2, "LeptonFinder2");
// Jets, anti-kt 0.4
VetoedFinalState fsJets(
FinalState(Cuts::abseta < 7.0)); //final state for jet finding: veto leptons and neutrinos
fsJets.vetoNeutrinos();
fsJets.addVetoOnThisFinalState(photon_fs);
fsJets.addVetoOnThisFinalState(chLep_fid);
declare(FastJets(fsJets, JetAlg::ANTIKT, 0.4), "Jets");
// b hadrons for b-tagging
declare(HeavyHadrons(Cuts::abseta < 2.5 && Cuts::pT > 5 * GeV), "Bhadrons");
// Missing momentum
declare(MissingMomentum(), "MET");
// Histograms
if (_mode != 2) {
book(_h_fiducial_3l, "d01-x01-y01");
}
if (_mode != 1) {
book(_h_2l2j, "d01-x01-y02");
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Get the dressed leptons, sorted by pT of their constituent bare lepton (!!)
DressedLeptons _vbs_lep = apply<LeptonFinder>(event, "LeptonFinder").dressedLeptons();
if (_vbs_lep.size() == 3 && _mode != 2) {
std::sort(_vbs_lep.begin(), _vbs_lep.end(), [](const DressedLepton& l1, const DressedLepton& l2) {
return (l1.bareLepton().pT() > l2.bareLepton().pT());
});
// Get the jets
const Jets& _vbs_jets = apply<FastJets>(event, "Jets")
.jetsByPt(Cuts::pT > 25 * GeV && Cuts::abseta < 4.5);
if (_vbs_jets.size() <= 1) {
// Determine nsfos pairs for channel classification
int nSFOS = 0;
for (size_t i = 0; i < _vbs_lep.size(); ++i) {
const double ch_l0 = _vbs_lep[i].charge();
for (size_t j = i + 1; j < _vbs_lep.size(); ++j) {
const double ch_l1 = _vbs_lep[j].charge();
if (_vbs_lep[i].abspid() == _vbs_lep[j].abspid() && ch_l0 * ch_l1 < 0) ++nSFOS;
}
}
double minDRll = DBL_MAX, mSFOS_MinDiff = DBL_MAX, meeSS_MinDiff = DBL_MAX, mSF_min = DBL_MAX;
for (size_t i = 0; i < _vbs_lep.size(); ++i) {
const double ch_l0 = _vbs_lep[i].charge();
for (size_t j = i + 1; j < _vbs_lep.size(); ++j) {
const double ch_l1 = _vbs_lep[j].charge();
const bool samesign = ch_l0 * ch_l1 > 0;
// Update min dR between leptons
minDRll = min(minDRll, deltaR(_vbs_lep[i], _vbs_lep[j]));
// Require same flavour
if (_vbs_lep[i].abspid() != _vbs_lep[j].abspid()) continue;
// SF dilepton mass (used several times)
const double mSF = (_vbs_lep[i].momentum() + _vbs_lep[j].momentum()).mass();
// Determine min for all same-flavor pairs
mSF_min = min(mSF, mSF_min);
// Determine min for all m_ee same-sign pairs
if (_vbs_lep[i].abspid() == PID::ELECTRON && samesign) {
if (fabs(mSF - ZMASS) < fabs(meeSS_MinDiff - ZMASS)) meeSS_MinDiff = mSF;
}
// Determine min for all mSFOS pairs
if (!samesign && fabs(mSF - ZMASS) < abs(mSFOS_MinDiff - ZMASS)) mSFOS_MinDiff = mSF;
}
}
bool setVeto = false;
if (minDRll < 0.1) setVeto = true;
if (nSFOS == 0 && mSF_min < 20 * GeV) setVeto = true;
if (nSFOS == 0 && fabs(meeSS_MinDiff - ZMASS) < 15 * GeV) setVeto = true;
if (nSFOS == 1 && ((ZMASS - mSFOS_MinDiff) < 35 * GeV && (mSFOS_MinDiff - ZMASS) < 20 * GeV))
setVeto = true;
if (nSFOS == 2 && fabs(mSFOS_MinDiff - ZMASS) < 20 * GeV) setVeto = true;
if (!setVeto) {
const Vector3& met = -1.0 * apply<MissingMomentum>(event, "MET").vectorEt();
if (nSFOS == 1 && met.mod() < 45 * GeV) setVeto = true;
if (nSFOS == 2 && met.mod() < 55 * GeV) setVeto = true;
if (!setVeto) {
const double dPhi = deltaPhi(
(_vbs_lep[0].momentum() + _vbs_lep[1].momentum() + _vbs_lep[2].momentum()), met);
if (dPhi < 2.5) setVeto = true;
}
// Fill histo
if (!setVeto) {
_h_fiducial_3l->fill();
}
}
}
}
if (_mode != 1) {
// Get leptons
DressedLeptons leps = apply<LeptonFinder>(event, "LeptonFinder").dressedLeptons();
if (leps.size() >= 2) {
// Sort the dressed leptons by pt of their constituent lepton (bare lepton pt)
std::sort(leps.begin(), leps.end(), [](const DressedLepton& l1, const DressedLepton& l2) {
return (l1.bareLepton().pT() > l2.bareLepton().pT());
});
if (leps[0].pT() < 30 * GeV || leps[0].abseta() > 2.5) vetoEvent;
if (leps[1].pT() < 30 * GeV || leps[1].abseta() > 2.5) vetoEvent;
// Get jets
const Jets& jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > 15 * GeV);
// Find min dilepton DR and mass
double minDRll = DBL_MAX, mll = DBL_MAX;
for (size_t i = 0; i < leps.size(); ++i) {
for (size_t j = i + 1; j < leps.size(); ++j) {
minDRll = min(minDRll, deltaR(leps[i], leps[j]));
mll = min(mll, (leps[i].momentum() + leps[j].momentum()).mass());
}
}
if (minDRll < 0.1) vetoEvent;
if (mll < 40 * GeV) vetoEvent;
// Require same-sign leading leptons
if (leps[0].charge() * leps[1].charge() < 0) vetoEvent;
// Veto di-electron combinations within 10 GeV of the Z mass
if (fabs(mll - 91.188 * GeV) < 10 * GeV && leps[0].abspid() == PID::ELECTRON
&& leps[1].abspid() == PID::ELECTRON)
vetoEvent;
// Now jet cuts
if (jets.size() < 2) vetoEvent;
if (jets[0].pT() < 30 * GeV || jets[0].abseta() > 2.5) vetoEvent;
if (jets[1].pT() < 20 * GeV || jets[1].abseta() > 2.5) vetoEvent;
// Find closest jet/lepton pair and veto if too close in phi or too far in eta
double minDRLepJets = DBL_MAX;
for (const Jet& jet : jets) {
for (const Particle& lep : leps) minDRLepJets = min(minDRLepJets, deltaR(lep, jet));
}
if (minDRLepJets < 0.3) vetoEvent;
if (fabs(deltaEta(jets[0], jets[1])) > 1.5) vetoEvent;
// Dijet mass requirement
double mjj = (jets[0].momentum() + jets[1].momentum()).mass();
if (mjj < 65 || mjj > 105) vetoEvent;
if (!inRange(mjj, 65 * GeV, 105 * GeV)) vetoEvent;
// Veto if any good jets are b-jets
const Particles& bhadrons = apply<HeavyHadrons>(event, "Bhadrons").bHadrons();
for (const Jet& j : jets) {
if (j.abseta() > 2.5) continue; // outside acceptance of b-tagging
const bool isbJet = any(bhadrons, deltaRLess(j, 0.3));
if (isbJet) vetoEvent;
}
// MET vetoing for non-muon events
const MissingMomentum& met = apply<MissingMomentum>(event, "MET");
if (met.vectorEt().mod() < 55 * GeV
&& (leps[0].abspid() != PID::MUON || leps[1].abspid() != PID::MUON))
vetoEvent;
// Fill counter
_h_2l2j->fill();
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
if (_mode != 2) {
scale(_h_fiducial_3l, crossSection() / sumOfWeights() / femtobarn);
}
if (_mode != 1) {
scale(_h_2l2j, crossSection() / sumOfWeights() / femtobarn);
}
}
/// @}
protected:
size_t _mode;
private:
/// @name Histograms
/// @{
const double ZMASS = 91.1876 * GeV;
CounterPtr _h_fiducial_3l;
CounterPtr _h_2l2j;
/// @}
};
RIVET_DECLARE_PLUGIN(ATLAS_2016_I1492320);
}