#include <TtDecayChannelSelector.h>

Public Types
enum	{ Elec = 0, Muon = 1, Tau = 2 }
	leafs of leptonic decay channel vector decay_ More...
typedef std::vector< int >	Decay
	typedef to simplify the decay vectors
Public Member Functions
bool	operator() (const reco::GenParticleCollection &parts, std::string inputType) const
	operator for decay channel selection
	TtDecayChannelSelector (const edm::ParameterSet &)
	std contructor
	~TtDecayChannelSelector ()
	default destructor
Private Member Functions
unsigned int	checkSum (const Decay &vec) const
unsigned int	countProngs (const reco::Candidate &part) const
	count the number of charged particles for tau decays
unsigned int	decayChannel () const
	return decay channel to select for from configuration
bool	search (reco::GenParticle::const_iterator &part, int pdgId, std::string &inputType) const
	search for particle with pdgId in given listing (for top daughters)
bool	search (reco::GenParticleCollection::const_iterator &part, int pdgId, std::string &inputType) const
	search for particle with pdgId in given listing (for top)
bool	tauDecay (const reco::Candidate &) const
	check tau decay to be leptonic, 1-prong or 3-prong
Private Attributes
bool	allow1Prong_
	allow 1-prong tau decays
bool	allow3Prong_
	allow 2-prong tau decays
Decay	allowedDecays_
bool	allowElectron_
	allow tau decays into electron
bool	allowMuon_
	allow tau decays into muon
Decay	decayBranchA_
	top decay branch 1
Decay	decayBranchB_
	top decay branch 2
bool	invert_
	invert selection
bool	restrictTauDecays_
	restrict tau decays

Detailed Description

Definition at line 8 of file TtDecayChannelSelector.h.

Member Typedef Documentation

typedef std::vector<int> TtDecayChannelSelector::Decay

typedef to simplify the decay vectors

Definition at line 15 of file TtDecayChannelSelector.h.

Member Enumeration Documentation

anonymous enum

leafs of leptonic decay channel vector decay_

Enumerator:

Elec
Muon
Tau

Definition at line 13 of file TtDecayChannelSelector.h.

{Elec=0, Muon=1, Tau =2};

Constructor & Destructor Documentation

TtDecayChannelSelector::TtDecayChannelSelector ( const edm::ParameterSet & cfg )

std contructor

Definition at line 18 of file TtDecayChannelSelector.cc.

References allow1Prong_, allow3Prong_, allowedDecays_, allowElectron_, allowMuon_, decayBranchA_, decayBranchB_, edm::ParameterSet::existsAs(), edm::ParameterSet::getParameter(), kDecayChannels, and restrictTauDecays_.

                                                                        :
  invert_ ( cfg.getParameter<bool>("invert" ) ),
  allowElectron_(false), allowMuon_(false), allow1Prong_(false), 
  allow3Prong_(false)
{
  // tau decays are not restricted if this PSet does not exist at all
  restrictTauDecays_=cfg.existsAs<edm::ParameterSet>("restrictTauDecays");
  // determine allowed tau decays
  if(restrictTauDecays_){
    edm::ParameterSet allowedTauDecays = cfg.getParameter<edm::ParameterSet>("restrictTauDecays");
    // tau decays are not restricted if none of the following parameters exists
    restrictTauDecays_=(allowedTauDecays.existsAs<bool>("electron"  )|| 
                        allowedTauDecays.existsAs<bool>("muon"  )|| 
                        allowedTauDecays.existsAs<bool>("oneProng"  )|| 
                        allowedTauDecays.existsAs<bool>("threeProng") );
    // specify the different possible restrictions of the tau decay channels
    allowElectron_ = (allowedTauDecays.existsAs<bool>("electron"  ) ? allowedTauDecays.getParameter<bool>("electron"  ) : false);
    allowMuon_ = (allowedTauDecays.existsAs<bool>("muon"  ) ? allowedTauDecays.getParameter<bool>("muon"  ) : false);
    allow1Prong_ = (allowedTauDecays.existsAs<bool>("oneProng"  ) ? allowedTauDecays.getParameter<bool>("oneProng"  ) : false); 
    allow3Prong_ = (allowedTauDecays.existsAs<bool>("threeProng") ? allowedTauDecays.getParameter<bool>("threeProng") : false);
  }
  // allowed top decays PSet
  edm::ParameterSet allowedTopDecays = cfg.getParameter<edm::ParameterSet>("allowedTopDecays");

  // fill decayBranchA_
  edm::ParameterSet decayBranchA = allowedTopDecays.getParameter<edm::ParameterSet>("decayBranchA");
  decayBranchA_.push_back(decayBranchA.getParameter<bool>("electron"));
  decayBranchA_.push_back(decayBranchA.getParameter<bool>("muon"    ));
  decayBranchA_.push_back(decayBranchA.getParameter<bool>("tau"     ));

  // fill decay branchB_
  edm::ParameterSet decayBranchB = allowedTopDecays.getParameter<edm::ParameterSet>("decayBranchB");
  decayBranchB_.push_back(decayBranchB.getParameter<bool>("electron"));
  decayBranchB_.push_back(decayBranchB.getParameter<bool>("muon"    ));
  decayBranchB_.push_back(decayBranchB.getParameter<bool>("tau"     ));

  // fill allowedDecays_
  for(unsigned int d=0; d<kDecayChannels; ++d){
    allowedDecays_.push_back(decayBranchA_[d]+decayBranchB_[d]);
  }
}

TtDecayChannelSelector::~TtDecayChannelSelector ( )

default destructor

Definition at line 60 of file TtDecayChannelSelector.cc.

{ 
}

Member Function Documentation

unsigned int TtDecayChannelSelector::checkSum ( const Decay & vec ) const [inline, private]

Definition at line 76 of file TtDecayChannelSelector.h.

Referenced by operator()().

{
  unsigned int sum=0;
  for(unsigned int d=0; d<vec.size(); ++d){
    sum+=vec[d];
  }
  return sum;
}

unsigned int TtDecayChannelSelector::countProngs ( const reco::Candidate & part ) const [private]

count the number of charged particles for tau decays

Definition at line 194 of file TtDecayChannelSelector.cc.

References reco::Candidate::begin(), reco::Candidate::charge(), reco::Candidate::end(), and reco::Candidate::status().

Referenced by tauDecay().

{
  // if stable, return 1 or 0
  if(part.status()==1){
    return (part.charge()!=0);
  }
  // if unstable, call recursively on daughters
  int prong =0;
  for(reco::Candidate::const_iterator daughter=part.begin();daughter!=part.end(); ++daughter){
    prong += countProngs(*daughter);
  }
  return prong;
}

unsigned int TtDecayChannelSelector::decayChannel ( ) const [inline, private]

return decay channel to select for from configuration

Definition at line 63 of file TtDecayChannelSelector.h.

References prof2calltree::count, decayBranchA_, and decayBranchB_.

Referenced by operator()().

{
  unsigned int channel=0;
  if( std::count(decayBranchA_.begin(), decayBranchA_.end(), 1) > 0 ){ 
    ++channel; 
  }
  if( std::count(decayBranchB_.begin(), decayBranchB_.end(), 1) > 0 ){ 
    ++channel; 
  }
  return channel;
}

bool TtDecayChannelSelector::operator()	(	const reco::GenParticleCollection &	parts,
		std::string	inputType
	)		const

operator for decay channel selection

Definition at line 65 of file TtDecayChannelSelector.cc.

References abs, accept(), allowedDecays_, TopDecayID::bID, checkSum(), decayBranchA_, decayBranchB_, decayChannel(), Elec, TopDecayID::elecID, invert_, funct::log(), Muon, TopDecayID::muonID, restrictTauDecays_, search(), Tau, tauDecay(), TopDecayID::tauID, TopDecayID::tID, and TopDecayID::WID.

{
  bool verbose=false; // set this to true for debugging and add TtDecayChannelSelector category to the MessageLogger in your cfg file
  unsigned int iLep=0;
  unsigned int iTop=0,iBeauty=0,iElec=0,iMuon=0,iTau=0;
  for(reco::GenParticleCollection::const_iterator top=parts.begin(); top!=parts.end(); ++top){
    if( search(top, TopDecayID::tID, inputType) ){
      ++iTop;
      for(reco::GenParticle::const_iterator td=top->begin(); td!=top->end(); ++td){
        if( search(td, TopDecayID::bID, inputType) ){
          ++iBeauty;
        }
        if( search(td, TopDecayID::WID, inputType) ){
          for(reco::GenParticle::const_iterator wd=td->begin(); wd!=td->end(); ++wd){
            if( std::abs(wd->pdgId())==TopDecayID::elecID ){
              ++iElec;
            }
            if( std::abs(wd->pdgId())==TopDecayID::muonID ){
              ++iMuon;
            }
            if( std::abs(wd->pdgId())==TopDecayID::tauID  ){ 
              if(restrictTauDecays_){
                // count as iTau if it is leptonic, one-prong
                // or three-prong and ignore increasing iLep
                // though else
                if(tauDecay(*wd)){
                  ++iTau; 
                } else{
                  ++iLep; 
                }
              }
              else{
                ++iTau;
              }
            }
          }
        }
      }
    }
  }
  if(verbose) {
    edm::LogVerbatim log("TtDecayChannelSelector");
    log << "----------------------"   << "\n"
        << " iTop    : " << iTop      << "\n"
        << " iBeauty : " << iBeauty   << "\n"
        << " iElec   : " << iElec     << "\n"
        << " iMuon   : " << iMuon     << "\n"
        << " iTau    : " << iTau+iLep;
    if(restrictTauDecays_ && (iTau+iLep)>0){
      log << " (" << iTau << ")\n";
    }
    else{
      log << "\n";
    }
    log << "- - - - - - - - - - - "   << "\n";
  }
  iLep+=iElec+iMuon+iTau;

  bool accept=false;
  unsigned int channel = decayChannel();
  if( (iTop==2) && (iBeauty==2) ){
    if( channel==iLep ){
      if( channel==0 ){
        // no lepton: accept without restriction we already 
        // know that the number of leptons is correct
        accept=true;
      }
      if( channel==1 ){
        // one lepton: check that this one is allowed
        accept=(iElec&&allowedDecays_[Elec]) || (iMuon&&allowedDecays_[Muon]) || (iTau&&allowedDecays_[Tau]);
      }
      if( channel==2 ){
        if( checkSum(allowedDecays_)==channel ){
          // no redundancy
          accept = (allowedDecays_[Elec]==(int)iElec) && (allowedDecays_[Muon]==(int)iMuon) && (allowedDecays_[Tau]==(int)iTau);
        }
        else{
          // reject events with wrong tau decays
          if(iElec+iMuon+iTau!=channel){
            accept = false;
          }
          else {
            if((iElec==2)||(iMuon==2)||(iTau==2)) {
              // same lepton twice: check that this is allowed.
              accept = (allowedDecays_[Elec]==(int)iElec)||(allowedDecays_[Muon]==(int)iMuon)||(allowedDecays_[Tau]==(int)iTau);
            } 
            else {
              // two different leptons: look if there is a possible combination
              accept = ( ((iElec&&decayBranchA_[Elec])&&((iMuon&&decayBranchB_[Muon])||(iTau &&decayBranchB_[Tau ]))) ||
                         ((iMuon&&decayBranchA_[Muon])&&((iElec&&decayBranchB_[Elec])||(iTau &&decayBranchB_[Tau ]))) ||
                         ((iTau &&decayBranchA_[Tau ])&&((iElec&&decayBranchB_[Elec])||(iMuon&&decayBranchB_[Muon])))   );
            }
          }
        }
      }
    }
    accept=( (!invert_&& accept) || (!(!invert_)&& !accept) );
  }
  else{
    edm::LogWarning ( "NoVtbDecay" ) << "Decay is not via Vtb";
  }
  if(verbose)
    edm::LogVerbatim("TtDecayChannelSelector") << " accept  : " << accept;
  return accept;
}

bool TtDecayChannelSelector::search	(	reco::GenParticleCollection::const_iterator &	part,
		int	pdgId,
		std::string &	inputType
	)		const `[private]`

search for particle with pdgId in given listing (for top)

Definition at line 172 of file TtDecayChannelSelector.cc.

References abs, kGenParticles, and TopDecayID::unfrag.

Referenced by operator()().

{
  if(inputType==kGenParticles){
    return (std::abs(part->pdgId())==pdgId && part->status()==TopDecayID::unfrag) ? true : false;
  }
  else{
    return (std::abs(part->pdgId())==pdgId) ? true : false;
  }
}

bool TtDecayChannelSelector::search	(	reco::GenParticle::const_iterator &	part,
		int	pdgId,
		std::string &	inputType
	)		const `[private]`

search for particle with pdgId in given listing (for top daughters)

Definition at line 183 of file TtDecayChannelSelector.cc.

References abs, kGenParticles, and TopDecayID::unfrag.

{
  if(inputType==kGenParticles){
    return (std::abs(part->pdgId())==pdgId && part->status()==TopDecayID::unfrag) ? true : false;
  }
  else{
    return (std::abs(part->pdgId())==pdgId) ? true : false;
  }
}

bool TtDecayChannelSelector::tauDecay ( const reco::Candidate & tau ) const [private]

check tau decay to be leptonic, 1-prong or 3-prong

Definition at line 209 of file TtDecayChannelSelector.cc.

References abs, allow1Prong_, allow3Prong_, allowElectron_, allowMuon_, reco::Candidate::begin(), countProngs(), TopDecayID::elecID, reco::Candidate::end(), TopDecayID::muonID, and reco::Candidate::pdgId().

Referenced by operator()().

{
  bool electronTau = false;
  bool muonTau = false;
  unsigned int nch = 0;
  // loop on tau decays, check for an elec
  // or muon and count charged particles
  for(reco::Candidate::const_iterator daughter=tau.begin();daughter!=tau.end(); ++daughter){
    // if the tau daughter is again a tau, this means that the particle has 
    // still to be propagated; in that case, return the result of the same 
    // method applied on the daughter of the current particle
    if(daughter->pdgId()==tau.pdgId()){
      return tauDecay(*daughter);
    }
    // check for electron from tau decay
    electronTau |= (std::abs(daughter->pdgId())==TopDecayID::elecID);
    // check for muon from tau decay
    muonTau |= (std::abs(daughter->pdgId())==TopDecayID::muonID);
    // count charged particles
    nch += countProngs(*daughter);
  }
  return ((allowElectron_ &&  electronTau)          ||
          (allowMuon_ && muonTau)||
          (allow1Prong_ && !electronTau && !muonTau && nch==1)||
          (allow3Prong_ && !electronTau && !muonTau && nch==3));
}