#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 More...

Public Member Functions
bool	operator() (const reco::GenParticleCollection &parts, std::string inputType) const
	operator for decay channel selection More...

	TtDecayChannelSelector (const edm::ParameterSet &)
	std contructor More...

	~TtDecayChannelSelector ()
	default destructor More...

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 More...

unsigned int	decayChannel () const
	return decay channel to select for from configuration More...

bool	search (reco::GenParticleCollection::const_iterator &part, int pdgId, std::string &inputType) const
	search for particle with pdgId in given listing (for top) More...

bool	search (reco::GenParticle::const_iterator &part, int pdgId, std::string &inputType) const
	search for particle with pdgId in given listing (for top daughters) More...

bool	tauDecay (const reco::Candidate &) const
	check tau decay to be leptonic, 1-prong or 3-prong More...

Private Attributes
bool	allow1Prong_
	allow 1-prong tau decays More...

bool	allow3Prong_
	allow 2-prong tau decays More...

Decay	allowedDecays_

bool	allowElectron_
	allow tau decays into electron More...

bool	allowMuon_
	allow tau decays into muon More...

Decay	decayBranchA_
	top decay branch 1 More...

Decay	decayBranchB_
	top decay branch 2 More...

bool	invert_
	invert selection More...

bool	restrictTauDecays_
	restrict tau decays More...

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.

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

TtDecayChannelSelector::Elec

Definition: TtDecayChannelSelector.h:13

TtDecayChannelSelector::Muon

Definition: TtDecayChannelSelector.h:13

TtDecayChannelSelector::Tau

Definition: TtDecayChannelSelector.h:13

Constructor & Destructor Documentation

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

std contructor

Definition at line 15 of file TtDecayChannelSelector.cc.

References allow1Prong_, allow3Prong_, allowedDecays_, allowElectron_, allowMuon_, ztail::d, 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 57 of file TtDecayChannelSelector.cc.

58 {

59 }

Member Function Documentation

unsigned int TtDecayChannelSelector::checkSum ( const Decay & vec ) const

inlineprivate

Definition at line 76 of file TtDecayChannelSelector.h.

References ztail::d.

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 191 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

inlineprivate

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 62 of file TtDecayChannelSelector.cc.

References funct::abs(), accept(), allowedDecays_, reco::Candidate::begin(), TopDecayID::bID, checkSum(), decayBranchA_, decayBranchB_, decayChannel(), Elec, TopDecayID::elecID, reco::Candidate::end(), invert_, cmsBatch::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 169 of file TtDecayChannelSelector.cc.

References funct::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 180 of file TtDecayChannelSelector.cc.

References funct::abs(), kGenParticles, reco::Candidate::pdgId(), reco::Candidate::status(), 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 206 of file TtDecayChannelSelector.cc.

References funct::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));
 }