Rivet analyses
Single lepton search for supersymmetry
Experiment: ATLAS (LHC)
Inspire ID: 1204092
Status: OBSOLETE
Authors: - Angela Chen
References: - Expt page: ATLAS-CONF-2011-090
Beams: p+ p+
Beam energies: (3500.0, 3500.0)GeV
Run details: - BSM signal events at 7000 GeV.
Single lepton search for supersymmmetric particles by ATLAS at 7 TeV. Event counts in electron and muon signal regions are implemented as one-bin histograms. Histograms for missing transverse energy and effective mass are implemented for the two signal regions.
Source
code:ATLAS_2011_CONF_2011_090.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/VisibleFinalState.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
#include "Rivet/Projections/VetoedFinalState.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
class ATLAS_2011_CONF_2011_090 : public Analysis {
public:
/// @name Constructors etc.
/// @{
/// Constructor
ATLAS_2011_CONF_2011_090()
: Analysis("ATLAS_2011_CONF_2011_090")
{ }
/// @}
public:
/// @name Analysis methods
/// @{
/// Book histograms and initialize 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");
// veto region electrons (from 2010 arXiv:1102.2357v2)
Cut vetocut = Cuts::absetaIn(1.37, 1.52);
IdentifiedFinalState veto_elecs(vetocut && Cuts::pT > 10*GeV);
veto_elecs.acceptIdPair(PID::ELECTRON);
declare(veto_elecs, "veto_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
VetoedFinalState vfs;
vfs.addVetoPairId(PID::MUON);
declare(FastJets(vfs, JetAlg::ANTIKT, 0.4), "AntiKtJets04");
// all tracks (to do deltaR with leptons)
declare(ChargedFinalState(Cuts::abseta < 3.0 && Cuts::pT > 0.5*GeV), "cfs");
// for pTmiss
declare(VisibleFinalState(Cuts::abseta < 4.9), "vfs");
/// Book histograms
book(_count_mu_channel ,"count_muon_channel", 1, 0., 1.);
book(_count_e_channel ,"count_electron_channel", 1, 0., 1.);
book(_hist_eTmiss_e ,"Et_miss_e", 50, 0., 500.);
book(_hist_eTmiss_mu ,"Et_miss_mu", 50, 0., 500.);
book(_hist_m_eff_e ,"m_eff_e", 60, 0., 1500.);
book(_hist_m_eff_mu ,"m_eff_mu", 60, 0., 1500.);
book(_hist_m_eff_e_final ,"m_eff_e_final", 15, 0., 1500.);
book(_hist_m_eff_mu_final ,"m_eff_mu_final", 15, 0., 1500.);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
Particles veto_e = apply<IdentifiedFinalState>(event, "veto_elecs").particles();
if ( ! veto_e.empty() ) {
MSG_DEBUG("electrons in veto region");
vetoEvent;
}
Jets cand_jets = apply<FastJets>(event, "AntiKtJets04").jetsByPt(Cuts::pT > 20*GeV && Cuts::abseta < 2.8);
Particles candtemp_e = apply<IdentifiedFinalState>(event, "elecs").particlesByPt();
Particles candtemp_mu = apply<IdentifiedFinalState>(event,"muons").particlesByPt();
Particles chg_tracks = apply<ChargedFinalState>(event, "cfs").particles();
Particles cand_mu;
Particles cand_e;
// pTcone around muon track
for ( const Particle& mu : candtemp_mu ) {
double pTinCone = -mu.pT();
for ( const Particle& track : chg_tracks ) {
if ( deltaR(mu, track) < 0.2 )
pTinCone += track.pT();
}
if ( pTinCone < 1.8*GeV )
cand_mu.push_back(mu);
}
// pTcone around electron
for ( const Particle& e : candtemp_e ) {
double pTinCone = -e.pT();
for ( const Particle& track : chg_tracks ) {
if ( deltaR(e, track) < 0.2 )
pTinCone += track.pT();
}
if ( pTinCone < 0.10 * e.pT() )
cand_e.push_back(e);
}
// discard jets that overlap with electrons
Jets cand_jets_2;
for ( const Jet& jet : cand_jets ) {
bool away_from_e = true;
for ( const Particle & e : cand_e ) {
if ( deltaR(e, jet) <= 0.2 ) {
away_from_e = false;
break;
}
}
if ( away_from_e )
cand_jets_2.push_back( jet );
}
// only consider leptons far from jet
Particles recon_e, recon_mu;
for ( const Particle & e : cand_e ) {
bool e_near_jet = false;
for ( const Jet& jet : cand_jets_2 ) {
if (inRange(deltaR(e, jet), 0.2, 0.4)) e_near_jet = true;
}
if ( ! e_near_jet ) recon_e.push_back( e );
}
for ( const Particle & mu : cand_mu ) {
bool mu_near_jet = false;
for ( const Jet& jet : cand_jets_2 ) {
if ( deltaR(mu, jet) < 0.4 ) mu_near_jet = true;
}
if ( ! mu_near_jet ) recon_mu.push_back( mu );
}
// pTmiss
Particles vfs_particles
= apply<VisibleFinalState>(event, "vfs").particles();
FourMomentum pTmiss;
for ( const Particle & p : vfs_particles ) {
pTmiss -= p.momentum();
}
double eTmiss = pTmiss.pT();
// final jet filter
Jets recon_jets;
for ( const Jet& jet : cand_jets_2 ) {
recon_jets.push_back( jet );
}
// ==================== observables ====================
// Njets
int Njets = 0;
double pTmiss_phi = pTmiss.phi();
for ( const Jet& jet : recon_jets ) {
if ( jet.abseta() < 2.8 )
Njets+=1;
}
if ( Njets < 3 ) {
MSG_DEBUG("Only " << Njets << " jets w/ eta<2.8 left");
vetoEvent;
}
if ( recon_jets[0].pT() <= 60.0 * GeV ) {
MSG_DEBUG("No hard leading jet in " << recon_jets.size() << " jets");
vetoEvent;
}
for ( int i = 1; i < 3; ++i ) {
if ( recon_jets[i].pT() <= 25*GeV ) {
vetoEvent;
}
}
for ( int i = 0; i < 3; ++i ) {
double dPhi = deltaPhi( pTmiss_phi, recon_jets[i].phi() );
if ( dPhi <= 0.2 ) {
MSG_DEBUG("dPhi too small");
vetoEvent;
break;
}
}
Particles lepton;
if ( recon_mu.empty() && recon_e.empty() ) {
MSG_DEBUG("No leptons");
vetoEvent;
}
else {
for ( const Particle & mu : recon_mu )
lepton.push_back(mu);
for ( const Particle & e : recon_e )
lepton.push_back(e);
}
std::sort(lepton.begin(), lepton.end(), cmpMomByPt);
double e_id = 11;
double mu_id = 13;
// one hard leading lepton cut
if ( lepton[0].abspid() == e_id &&
lepton[0].pT() <= 25*GeV ) {
vetoEvent;
}
else if ( lepton[0].abspid() == mu_id &&
lepton[0].pT() <= 20*GeV ) {
vetoEvent;
}
// exactly one hard leading lepton cut
if(lepton.size()>1) {
if ( lepton[1].abspid() == e_id &&
lepton[1].pT() > 20*GeV ) {
vetoEvent;
}
else if ( lepton[1].abspid() == mu_id &&
lepton[1].pT() > 10*GeV ) {
vetoEvent;
}
}
// ==================== FILL ====================
FourMomentum pT_l = lepton[0].momentum();
double dPhi = deltaPhi( pT_l.phi(), pTmiss_phi);
double mT = sqrt( 2 * pT_l.pT() * eTmiss * (1 - cos(dPhi)) );
// effective mass
double m_eff = eTmiss + pT_l.pT()
+ recon_jets[0].pT()
+ recon_jets[1].pT()
+ recon_jets[2].pT();
// Electron channel signal region
if ( lepton[0].abspid() == e_id ) {
_hist_eTmiss_e->fill(eTmiss);
_hist_m_eff_e->fill(m_eff);
if ( mT > 100*GeV && eTmiss > 125*GeV ) {
_hist_m_eff_e_final->fill(m_eff);
if ( m_eff > 500*GeV && eTmiss > 0.25*m_eff ) {
_count_e_channel->fill(0.5);
}
}
}
// Muon channel signal region
else if ( lepton[0].abspid() == mu_id ) {
_hist_eTmiss_mu->fill(eTmiss);
_hist_m_eff_mu->fill(m_eff);
if ( mT > 100*GeV && eTmiss > 125*GeV ) {
_hist_m_eff_mu_final->fill(m_eff);
if ( m_eff > 500*GeV && eTmiss > 0.25*m_eff ) {
_count_mu_channel->fill(0.5);
}
}
}
}
/// @}
void finalize() {
scale( _hist_eTmiss_e , 10. * 165. * crossSection()/picobarn/sumOfWeights() );
scale( _hist_eTmiss_mu , 10. * 165. * crossSection()/picobarn/sumOfWeights() );
scale( _hist_m_eff_e , 25. * 165. * crossSection()/picobarn/sumOfWeights() );
scale( _hist_m_eff_mu , 25. * 165. * crossSection()/picobarn/sumOfWeights() );
scale( _hist_m_eff_e_final , 100. * 165. * crossSection()/picobarn/sumOfWeights() );
scale( _hist_m_eff_mu_final, 100. * 165. * crossSection()/picobarn/sumOfWeights() );
}
private:
/// @name Histograms
/// @{
Histo1DPtr _count_e_channel;
Histo1DPtr _count_mu_channel;
Histo1DPtr _hist_eTmiss_e;
Histo1DPtr _hist_eTmiss_mu;
Histo1DPtr _hist_m_eff_e;
Histo1DPtr _hist_m_eff_mu;
Histo1DPtr _hist_m_eff_e_final;
Histo1DPtr _hist_m_eff_mu_final;
/// @}
};
RIVET_DECLARE_PLUGIN(ATLAS_2011_CONF_2011_090);
}