Rivet analyses
title: ATLAS_2011_I930002
0-lepton squark and gluino search
Experiment: ATLAS (LHC)
Inspire ID: 930002
Status: VALIDATED
Authors: - Chris Wymant - David Grellscheid
References: - Expt page: ATLAS-SUSY-2011-07 - arXiv: 1109.6572
Beams: p+ p+
Beam energies: (3500.0, 3500.0)GeV
Run details: - BSM signal events at 7000 GeV.
0-lepton search for squarks and gluinos by ATLAS at 7 TeV with an integrated luminosity of $1.04\,\mathrm{fb}^{-1}$. Event counts in five signal regions are implemented as one-bin histograms.
Source code:ATLAS_2011_I930002.cc
```c++ // -- C++ --
include "Rivet/Analysis.hh"
include "Rivet/Projections/ChargedFinalState.hh"
include "Rivet/Projections/FastJets.hh"
include "Rivet/Projections/FinalState.hh"
include "Rivet/Projections/IdentifiedFinalState.hh"
include "Rivet/Projections/VisibleFinalState.hh"
namespace Rivet {
/// @brief 0-lepton squark and gluino search /// /// @author Chris Wymant class ATLAS_2011_I930002 : public Analysis { public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2011_I930002);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Projection to find the electrons
IdentifiedFinalState elecs(Cuts::abseta < 2.47 && Cuts::pT > 20 * GeV);
elecs.acceptIdPair(PID::ELECTRON);
declare(elecs, "elecs");
// Projection to find the muons
IdentifiedFinalState muons(Cuts::abseta < 2.4 && Cuts::pT > 10 * GeV);
muons.acceptIdPair(PID::MUON);
declare(muons, "muons");
// Jet finder
declare(FastJets(FinalState(), JetAlg::ANTIKT, 0.4), "AntiKtJets04");
// All tracks (to do deltaR with leptons)
declare(ChargedFinalState(Cuts::abseta < 3.0), "cfs");
// Used for pTmiss (N.B. the real 'vfs' extends beyond 4.5 to |eta| = 4.9)
declare(VisibleFinalState(Cuts::abseta < 4.5), "vfs");
// Book histograms
book(_count_2j, "count_2j", 1, 0., 1.);
book(_count_3j, "count_3j", 1, 0., 1.);
book(_count_4j5, "count_4j5", 1, 0., 1.);
book(_count_4j10, "count_4j10", 1, 0., 1.);
book(_count_HM, "count_HM", 1, 0., 1.);
book(_hist_meff_2j, 1, 1, 1);
book(_hist_meff_3j, 2, 1, 1);
book(_hist_meff_4j, 3, 1, 1);
book(_hist_meff_HM, 4, 1, 1);
book(_hist_eTmiss, "Et_miss", 20, 0., 1000.);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const Jets& cand_jets = apply<FastJets>(event, "AntiKtJets04")
.jetsByPt(Cuts::pT > 20 * GeV && Cuts::abseta < 4.9);
const Particles cand_e = apply<IdentifiedFinalState>(event, "elecs").particlesByPt();
// Muon isolation not mentioned in hep-exp 1109.6572, unlike in 1102.5290,
// but assumed to still be applicable
Particles cand_mu;
const Particles chg_tracks = apply<ChargedFinalState>(event, "cfs").particles();
const Particles muons = apply<IdentifiedFinalState>(event, "muons").particlesByPt();
for (const Particle& mu : muons) {
double pTinCone = -mu.pT();
for (const Particle& track : chg_tracks) {
if (deltaR(mu.momentum(), track.momentum()) <= 0.2) {
pTinCone += track.pT();
}
}
if (pTinCone < 1.8 * GeV) cand_mu.push_back(mu);
}
// Resolve jet-lepton overlap for jets with |eta| < 2.8
Jets cand_jets_2;
for (const Jet& jet : cand_jets) {
if (fabs(jet.eta()) >= 2.8) {
cand_jets_2.push_back(jet);
}
else {
bool away_from_e = true;
for (const Particle& e : cand_e) {
if (deltaR(e.momentum(), jet.momentum()) <= 0.2) {
away_from_e = false;
break;
}
}
if (away_from_e) cand_jets_2.push_back(jet);
}
}
Particles recon_e, recon_mu;
for (const Particle& e : cand_e) {
bool away = true;
for (const Jet& jet : cand_jets_2) {
if (deltaR(e.momentum(), jet.momentum()) < 0.4) {
away = false;
break;
}
}
if (away) recon_e.push_back(e);
}
for (const Particle& mu : cand_mu) {
bool away = true;
for (const Jet& jet : cand_jets_2) {
if (deltaR(mu.momentum(), jet.momentum()) < 0.4) {
away = false;
break;
}
}
if (away) recon_mu.push_back(mu);
}
// pTmiss
// Based on all candidate electrons, muons and jets, plus everything else with |eta| < 4.5
// i.e. everything in our projection "vfs" plus the jets with |eta| > 4.5
Particles vfs_particles = apply<VisibleFinalState>(event, "vfs").particles();
FourMomentum pTmiss;
for (const Particle& p : vfs_particles) {
pTmiss -= p.momentum();
}
for (const Jet& jet : cand_jets_2) {
if (fabs(jet.eta()) > 4.5) pTmiss -= jet.momentum();
}
double eTmiss = pTmiss.pT();
// Final jet filter
Jets recon_jets;
for (const Jet& jet : cand_jets_2) {
if (fabs(jet.eta()) <= 2.8) recon_jets.push_back(jet);
}
// NB. It seems that jets with |eta| > 2.8 could have been thrown away at
// the start; we don't do so, in order to follow both the structure of
// the paper and the similar Rivet analysis ATLAS_2011_S8983313
// 'candidate' muons needed only 10 GeV, to cause a veto they need 20 GeV
Particles veto_mu;
for (const Particle& mu : cand_mu) {
if (mu.pT() >= 20.0 * GeV) veto_mu.push_back(mu);
}
if (!(veto_mu.empty() && recon_e.empty())) {
MSG_DEBUG("Charged leptons left after selection");
vetoEvent;
}
if (eTmiss <= 130 * GeV) {
MSG_DEBUG("Not enough eTmiss: " << eTmiss << " < 130");
vetoEvent;
}
if (recon_jets.empty() || recon_jets[0].pT() <= 130.0 * GeV) {
MSG_DEBUG("No hard leading jet in " << recon_jets.size() << " jets");
vetoEvent;
}
// ==================== observables ====================
int Njets = 0;
double min_dPhi = 999.999;
double pTmiss_phi = pTmiss.phi();
for (const Jet& jet : recon_jets) {
if (jet.pT() > 40 * GeV) {
if (Njets < 3) {
min_dPhi = min(min_dPhi, deltaPhi(pTmiss_phi, jet.phi()));
}
++Njets;
}
}
int NjetsHighMass = 0;
for (const Jet& jet : recon_jets) {
if (jet.pT() > 80.0 * GeV) {
++NjetsHighMass;
}
}
if (Njets < 2) {
MSG_DEBUG("Only " << Njets << " >40 GeV jets left");
vetoEvent;
}
if (min_dPhi <= 0.4) {
MSG_DEBUG("dPhi too small");
vetoEvent;
}
// m_eff
double m_eff_2j = eTmiss + recon_jets[0].pT() + recon_jets[1].pT();
double m_eff_3j = recon_jets.size() < 3 ? -999.0 : m_eff_2j + recon_jets[2].pT();
double m_eff_4j = recon_jets.size() < 4 ? -999.0 : m_eff_3j + recon_jets[3].pT();
double m_eff_HM = eTmiss;
for (const Jet& jet : recon_jets) {
if (jet.pT() > 40.0 * GeV) m_eff_HM += jet.pT();
}
double et_meff_2j = eTmiss / m_eff_2j;
double et_meff_3j = eTmiss / m_eff_3j;
double et_meff_4j = eTmiss / m_eff_4j;
double et_meff_HM = eTmiss / m_eff_HM;
// ==================== FILL ====================
MSG_DEBUG("Trying to fill " << Njets << ' ' << m_eff_2j << ' ' << et_meff_2j << ' ' << m_eff_3j << ' '
<< et_meff_3j << ' ' << m_eff_4j << ' ' << et_meff_4j << ' ' << m_eff_HM
<< ' ' << et_meff_HM);
_hist_eTmiss->fill(eTmiss);
// 2j region
if (et_meff_2j > 0.3) {
_hist_meff_2j->fill(m_eff_2j);
if (m_eff_2j > 1000 * GeV) {
MSG_DEBUG("Hits 2j");
_count_2j->fill(0.5);
}
}
// 3j region
if (Njets >= 3 && et_meff_3j > 0.25) {
_hist_meff_3j->fill(m_eff_3j);
if (m_eff_3j > 1000 * GeV) {
MSG_DEBUG("Hits 3j");
_count_3j->fill(0.5);
}
}
// 4j5 & 4j10 regions
if (Njets >= 4 && et_meff_4j > 0.25) {
_hist_meff_4j->fill(m_eff_4j);
if (m_eff_4j > 500 * GeV) {
MSG_DEBUG("Hits 4j5");
_count_4j5->fill(0.5);
}
if (m_eff_4j > 1000 * GeV) {
MSG_DEBUG("Hits 4j10");
_count_4j10->fill(0.5);
}
}
// High mass region
if (NjetsHighMass >= 4 && et_meff_HM > 0.2) {
_hist_meff_HM->fill(m_eff_HM);
if (m_eff_HM > 1100 * GeV) {
MSG_DEBUG("Hits HM");
_count_HM->fill(0.5);
}
}
}
void finalize() {
// Two, three and four jet channels have bin width = 100 (GeV)
// High mass channel has bin width = 150 (GeV)
// Integrated luminosity = 1040 (pb)
scale(_hist_meff_2j, 100. * 1040 * crossSection() / picobarn / sumOfWeights());
scale(_hist_meff_3j, 100. * 1040 * crossSection() / picobarn / sumOfWeights());
scale(_hist_meff_4j, 100. * 1040 * crossSection() / picobarn / sumOfWeights());
scale(_hist_meff_HM, 150. * 1040 * crossSection() / picobarn / sumOfWeights());
}
/// @}
private:
Histo1DPtr _count_2j;
Histo1DPtr _count_3j;
Histo1DPtr _count_4j5;
Histo1DPtr _count_4j10;
Histo1DPtr _count_HM;
Histo1DPtr _hist_meff_2j;
Histo1DPtr _hist_meff_3j;
Histo1DPtr _hist_meff_4j;
Histo1DPtr _hist_meff_HM;
Histo1DPtr _hist_eTmiss;
};
RIVET_DECLARE_ALIASED_PLUGIN(ATLAS_2011_I930002, ATLAS_2011_S9212183);
} ```
Aliases: - ATLAS_2011_S9212183