#include <HLTDisplacedmumuFilter.h>

Inheritance diagram for HLTDisplacedmumuFilter:

Public Member Functions
virtual void	beginJob ()
virtual void	endJob ()
virtual bool	filter (edm::Event &, const edm::EventSetup &)
	HLTDisplacedmumuFilter (const edm::ParameterSet &)
	~HLTDisplacedmumuFilter ()
Private Attributes
edm::InputTag	beamSpotTag_
edm::InputTag	DisplacedVertexTag_
bool	fastAccept_
double	maxNormalisedChi2_
double	minCosinePointingAngle_
double	minLxySignificance_
edm::InputTag	MuonTag_
bool	saveTag_

Detailed Description

Definition at line 6 of file HLTDisplacedmumuFilter.h.

Constructor & Destructor Documentation

HLTDisplacedmumuFilter::HLTDisplacedmumuFilter ( const edm::ParameterSet & iConfig ) [explicit]

Definition at line 33 of file HLTDisplacedmumuFilter.cc.

                                                                            :
 
  fastAccept_ (iConfig.getParameter<bool>("FastAccept")),
  minLxySignificance_ (iConfig.getParameter<double>("MinLxySignificance")),
  maxNormalisedChi2_ (iConfig.getParameter<double>("MaxNormalisedChi2")), 
  minCosinePointingAngle_ (iConfig.getParameter<double>("MinCosinePointingAngle")),
  saveTag_ (iConfig.getUntrackedParameter<bool> ("SaveTag",false)),
  DisplacedVertexTag_(iConfig.getParameter<edm::InputTag>("DisplacedVertexTag")),
  beamSpotTag_ (iConfig.getParameter<edm::InputTag> ("BeamSpotTag")),
  MuonTag_ (iConfig.getParameter<edm::InputTag>("MuonTag"))
 
{

  produces<trigger::TriggerFilterObjectWithRefs>();
}

HLTDisplacedmumuFilter::~HLTDisplacedmumuFilter ( )

Definition at line 50 of file HLTDisplacedmumuFilter.cc.

{

}

Member Function Documentation

void HLTDisplacedmumuFilter::beginJob ( void ) [virtual]

Reimplemented from edm::EDFilter.

Definition at line 57 of file HLTDisplacedmumuFilter.cc.

{

}

void HLTDisplacedmumuFilter::endJob ( void ) [virtual]

Reimplemented from edm::EDFilter.

Definition at line 63 of file HLTDisplacedmumuFilter.cc.

{
        
}

bool HLTDisplacedmumuFilter::filter	(	edm::Event &	iEvent,
		const edm::EventSetup &	iSetup
	)		`[virtual]`

Implements HLTFilter.

Definition at line 69 of file HLTDisplacedmumuFilter.cc.

References beamSpotTag_, DisplacedVertexTag_, reco::BeamSpot::dxdz(), reco::BeamSpot::dydz(), reco::Vertex::error(), Exception, edm::Ref< C, T, F >::get(), edm::Event::getByLabel(), LogDebug, maxNormalisedChi2_, minCosinePointingAngle_, minLxySignificance_, module(), MuonTag_, reco::Vertex::normalizedChi2(), path(), reco::Vertex::position(), edm::Event::put(), saveTag_, mathSSE::sqrt(), reco::Vertex::tracks_begin(), reco::Vertex::tracksSize(), trigger::TriggerMuon, reco::BeamSpot::x0(), reco::BeamSpot::y0(), and reco::BeamSpot::z0().

{


  // get beam spot
  reco::BeamSpot vertexBeamSpot;
  edm::Handle<reco::BeamSpot> recoBeamSpotHandle;
  iEvent.getByLabel(beamSpotTag_,recoBeamSpotHandle);
  vertexBeamSpot = *recoBeamSpotHandle;
 
  
  // get displaced vertices
  reco::VertexCollection displacedVertexColl;
  edm::Handle<reco::VertexCollection> displacedVertexCollHandle;
  bool foundVertexColl = iEvent.getByLabel(DisplacedVertexTag_, displacedVertexCollHandle);
  if(foundVertexColl) displacedVertexColl = *displacedVertexCollHandle;
  
 
  // get muon collection
  edm::Handle<reco::RecoChargedCandidateCollection> mucands;
  iEvent.getByLabel (MuonTag_,mucands);
 
  // All HLT filters must create and fill an HLT filter object,
  // recording any reconstructed physics objects satisfying (or not)
  // this HLT filter, and place it in the Event.
  

  // Ref to Candidate object to be recorded in filter object
  reco::RecoChargedCandidateRef ref1;
  reco::RecoChargedCandidateRef ref2;

  std::auto_ptr<trigger::TriggerFilterObjectWithRefs> filterobject (new trigger::TriggerFilterObjectWithRefs(path(),module()));
  if(saveTag_)    filterobject->addCollectionTag(MuonTag_);

  
  bool triggered = false;
 
  // loop over vertex collection
  for(reco::VertexCollection::iterator it = displacedVertexColl.begin(); it!= displacedVertexColl.end(); it++){
          reco::Vertex displacedVertex = *it;
        
          // check if the vertex actually consists of exactly two muon tracks, throw exception if not
          if(displacedVertex.tracksSize() != 2)  throw cms::Exception("BadLogic") << "HLTDisplacedmumuFilter: ERROR: the Jpsi vertex must have exactly two muons by definition. It now has n muons = "
                                                                                    << displacedVertex.tracksSize() << std::endl;
       
          float normChi2 = displacedVertex.normalizedChi2();
          if (normChi2 > maxNormalisedChi2_) continue;
 
          // get the two muons from the vertex
          reco::Vertex::trackRef_iterator trackIt =  displacedVertex.tracks_begin();
          reco::TrackRef vertextkRef1 =  (*trackIt).castTo<reco::TrackRef>() ;
          // the second one
          trackIt++;
          reco::TrackRef vertextkRef2 =  (*trackIt).castTo<reco::TrackRef>();
          
          // calculate two-track transverse momentum
          math::XYZVector pperp(vertextkRef1->px() + vertextkRef2->px(),
                                  vertextkRef1->py() + vertextkRef2->py(),
                                  0.);
          
        
          reco::Vertex::Point vpoint=displacedVertex.position();
          //translate to global point, should be improved
          GlobalPoint secondaryVertex (vpoint.x(), vpoint.y(), vpoint.z());

          reco::Vertex::Error verr = displacedVertex.error();
          // translate to global error, should be improved
          GlobalError err(verr.At(0,0), verr.At(1,0), verr.At(1,1), verr.At(2,0), verr.At(2,1), verr.At(2,2) );

          GlobalPoint displacementFromBeamspot( -1*((vertexBeamSpot.x0() -  secondaryVertex.x()) +  (secondaryVertex.z() - vertexBeamSpot.z0()) * vertexBeamSpot.dxdz()),
                                                  -1*((vertexBeamSpot.y0() - secondaryVertex.y())+  (secondaryVertex.z() - vertexBeamSpot.z0()) * vertexBeamSpot.dydz()), 0);
        
          float lxy = displacementFromBeamspot.perp();
          float lxyerr = sqrt(err.rerr(displacementFromBeamspot));
        
        
          //calculate the angle between the decay length and the mumu momentum
          reco::Vertex::Point vperp(displacementFromBeamspot.x(),displacementFromBeamspot.y(),0.);
         
          float cosAlpha = vperp.Dot(pperp)/(vperp.R()*pperp.R());
        
          // check thresholds
          if (cosAlpha < minCosinePointingAngle_) continue;
       
          if (lxy/lxyerr < minLxySignificance_) continue;
        
          triggered = true;
 
          // now add the muons that passed to the filter object
          
          reco::RecoChargedCandidateCollection::const_iterator cand1;
          reco::RecoChargedCandidateCollection::const_iterator cand2;     

          // first find these two tracks in the muon collection
          int iFoundRefs = 0;
          for (reco::RecoChargedCandidateCollection::const_iterator cand=mucands->begin(); cand!=mucands->end(); cand++) {
            reco::TrackRef tkRef = cand->get<reco::TrackRef>();
            if(tkRef == vertextkRef1) {cand1 = cand; iFoundRefs++;}
            if(tkRef == vertextkRef2) {cand2 = cand; iFoundRefs++;}
          }
          if(iFoundRefs != 2) throw cms::Exception("BadLogic") << "HLTDisplacedmumuFilter: ERROR: the Jpsi vertex must have exactly two muons by definition."  << std::endl; 
          
          ref1=reco::RecoChargedCandidateRef( edm::Ref<reco::RecoChargedCandidateCollection>    (mucands,distance(mucands->begin(), cand1)));
          filterobject->addObject(trigger::TriggerMuon,ref1);
          
          ref2=reco::RecoChargedCandidateRef( edm::Ref<reco::RecoChargedCandidateCollection> (mucands,distance(mucands->begin(),cand2 )));
          filterobject->addObject(trigger::TriggerMuon,ref2);
  }


  // put filter object into the Event
  
  iEvent.put(filterobject);
  LogDebug("HLTDisplacedMumuFilter") << " >>>>> Result of HLTDisplacedMumuFilter is "<< triggered <<std::endl; 

  return triggered;
}