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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/VetoedFinalState.hh"
#include "Rivet/Projections/InvMassFinalState.hh"
namespace Rivet {
/// @brief CDF Run II Z + b-jet cross-section measurement
class CDF_2008_S8095620 : public Analysis {
public:
RIVET_DEFAULT_ANALYSIS_CTOR(CDF_2008_S8095620);
/// @name Analysis methods
//@{
void init() {
// Set up projections
const FinalState fs((Cuts::etaIn(-3.2, 3.2)));
declare(fs, "FS");
// Create a final state with any e+e- or mu+mu- pair with
// invariant mass 76 -> 106 GeV and ET > 18 (Z decay products)
vector<pair<PdgId,PdgId> > vids;
vids.push_back(make_pair(PID::ELECTRON, PID::POSITRON));
vids.push_back(make_pair(PID::MUON, PID::ANTIMUON));
FinalState fs2((Cuts::etaIn(-3.2, 3.2)));
InvMassFinalState invfs(fs2, vids, 76*GeV, 106*GeV);
declare(invfs, "INVFS");
// Make a final state without the Z decay products for jet clustering
VetoedFinalState vfs(fs);
vfs.addVetoOnThisFinalState(invfs);
declare(vfs, "VFS");
declare(FastJets(vfs, FastJets::CDFMIDPOINT, 0.7), "Jets");
// Book histograms
book(_dStot ,1, 1, 1);
book(_dSdET ,2, 1, 1);
book(_dSdETA ,3, 1, 1);
book(_dSdZpT ,4, 1, 1);
book(_dSdNJet ,5, 1, 1);
book(_dSdNbJet ,6, 1, 1);
book(_sumWeightSelected,"sumWeightSelected");
}
// Do the analysis
void analyze(const Event& event) {
// Check we have an l+l- pair that passes the kinematic cuts
// Get the Z decay products (mu+mu- or e+e- pair)
const InvMassFinalState& invMassFinalState = apply<InvMassFinalState>(event, "INVFS");
const Particles& ZDecayProducts = invMassFinalState.particles();
// make sure we have 2 Z decay products (mumu or ee)
if (ZDecayProducts.size() < 2) vetoEvent;
//new cuts
double Lep1Pt = ZDecayProducts[0].perp();
double Lep2Pt = ZDecayProducts[1].perp();
double Lep1Eta = fabs(ZDecayProducts[0].rapidity());
double Lep2Eta = fabs(ZDecayProducts[1].rapidity());
if (Lep1Eta > _LepEtaCut || Lep2Eta > _LepEtaCut) vetoEvent;
if (ZDecayProducts[0].abspid()==13 &&
((Lep1Eta > 1.5 || Lep2Eta > 1.5) || (Lep1Eta > 1.0 && Lep2Eta > 1.0))) {
vetoEvent;
}
if (Lep1Pt > Lep2Pt) {
if (Lep1Pt < _Lep1PtCut || Lep2Pt < _Lep2PtCut) vetoEvent;
}
else {
if (Lep1Pt < _Lep2PtCut || Lep2Pt < _Lep1PtCut) vetoEvent;
}
_sumWeightSelected->fill();
/// @todo: write out a warning if there are more than two decay products
FourMomentum Zmom = ZDecayProducts[0].momentum() + ZDecayProducts[1].momentum();
// Put all b-quarks in a vector
/// @todo Use a b-hadron search rather than b-quarks for tagging
Particles bquarks;
for(ConstGenParticlePtr p: HepMCUtils::particles(event.genEvent())) {
if (std::abs(p->pdg_id()) == PID::BQUARK) {
bquarks += Particle(*p);
}
}
// Get jets
const FastJets& jetpro = apply<FastJets>(event, "Jets");
MSG_DEBUG("Jet multiplicity before any pT cut = " << jetpro.size());
const PseudoJets& jets = jetpro.pseudoJetsByPt();
MSG_DEBUG("jetlist size = " << jets.size());
int numBJet = 0;
int numJet = 0;
// for each b-jet plot the ET and the eta of the jet, normalise to the total cross section at the end
// for each event plot N jet and pT(Z), normalise to the total cross section at the end
for (PseudoJets::const_iterator jt = jets.begin(); jt != jets.end(); ++jt) {
// select jets that pass the kinematic cuts
if (jt->perp() > _JetPtCut && fabs(jt->rapidity()) <= _JetEtaCut) {
numJet++;
// does the jet contain a b-quark?
bool bjet = false;
for (const Particle& bquark : bquarks) {
if (deltaR(jt->rapidity(), jt->phi(), bquark.rapidity(),bquark.phi()) <= _Rjet) {
bjet = true;
break;
}
} // end loop around b-jets
if (bjet) {
numBJet++;
_dSdET->fill(jt->perp());
_dSdETA->fill(fabs(jt->rapidity()));
}
}
} // end loop around jets
// wasn't asking for b-jets before!!!!
if(numJet > 0 && numBJet > 0) _dSdNJet->fill(numJet);
if(numBJet > 0) {
_dStot->fill(1960.0);
_dSdNbJet->fill(numBJet);
_dSdZpT->fill(Zmom.pT());
}
}
// Finalize
void finalize() {
// normalise histograms
// scale by 1 / the sum-of-weights of events that pass the Z cuts
// since the cross sections are normalized to the inclusive
// Z cross sections.
double Scale = 1.0;
if (_sumWeightSelected->val() != 0.0) Scale = 1.0/dbl(*_sumWeightSelected);
scale(_dStot,Scale);
scale(_dSdET,Scale);
scale(_dSdETA,Scale);
scale(_dSdNJet,Scale);
scale(_dSdNbJet,Scale);
scale(_dSdZpT,Scale);
}
//@}
private:
/// @name Cuts
/// @{
const double _Rjet = 0.7;
const double _JetPtCut = 20;
const double _JetEtaCut = 1.5;
const double _Lep1PtCut = 18;
const double _Lep2PtCut = 10;
const double _LepEtaCut = 3.2;
/// @}
/// Counter
CounterPtr _sumWeightSelected;
/// @name Histograms
/// @{
Histo1DPtr _dStot;
Histo1DPtr _dSdET;
Histo1DPtr _dSdETA;
Histo1DPtr _dSdNJet;
Histo1DPtr _dSdNbJet;
Histo1DPtr _dSdZpT;
/// @}
};
RIVET_DECLARE_ALIASED_PLUGIN(CDF_2008_S8095620, CDF_2008_I806082);
}
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