CSCHaloAlgo.cc

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#include "RecoMET/METAlgorithms/interface/CSCHaloAlgo.h"
#include "FWCore/Common/interface/TriggerNames.h"
/*
  [class]:  CSCHaloAlgo
  [authors]: R. Remington, The University of Florida
  [description]: See CSCHaloAlgo.h
  [date]: October 15, 2009
*/
using namespace reco;
using namespace std;
using namespace edm;
#include "TMath.h"

CSCHaloAlgo::CSCHaloAlgo()
{
  deta_threshold = 0.;
  min_inner_radius = 0.;
  max_inner_radius = 9999.;
  min_outer_radius = 0.;
  max_outer_radius = 9999.;
  dphi_threshold = 999.;
  norm_chi2_threshold = 999.;
  recHit_t0=0.;
  recHit_twindow=25.;
  expected_BX=3;
  max_dt_muon_segment=-10.0;
  max_free_inverse_beta=0.0;
  
  min_outer_theta = 0.;
  max_outer_theta = TMath::Pi();
  
  matching_dphi_threshold = 0.18; //radians
  matching_deta_threshold = 0.4;
  matching_dwire_threshold = 5.;


  et_thresh_rh_hbhe=25; //GeV
  et_thresh_rh_ee=10; 
  et_thresh_rh_eb=10; 

  dphi_thresh_segvsrh_hbhe=0.05; //radians
  dphi_thresh_segvsrh_eb=0.05;
  dphi_thresh_segvsrh_ee=0.05; 

  dr_lowthresh_segvsrh_hbhe=-20; //cm
  dr_lowthresh_segvsrh_eb=-20; 
  dr_lowthresh_segvsrh_ee=-20;

  dr_highthresh_segvsrh_hbhe=20; //cm
  dr_highthresh_segvsrh_eb=20; 
  dr_highthresh_segvsrh_ee=20;

  dt_lowthresh_segvsrh_hbhe=5;//ns
  dt_lowthresh_segvsrh_eb=5;
  dt_lowthresh_segvsrh_ee=5;

  dt_highthresh_segvsrh_hbhe=30;//ns
  dt_highthresh_segvsrh_eb=30;
  dt_highthresh_segvsrh_ee=30;


  geo = 0;


  
}

reco::CSCHaloData CSCHaloAlgo::Calculate(const CSCGeometry& TheCSCGeometry,
                     edm::Handle<reco::MuonCollection>& TheCosmicMuons,  
                     const edm::Handle<reco::MuonTimeExtraMap> TheCSCTimeMap,
                     edm::Handle<reco::MuonCollection>& TheMuons,
                     edm::Handle<CSCSegmentCollection>& TheCSCSegments, 
                     edm::Handle<CSCRecHit2DCollection>& TheCSCRecHits,
                     edm::Handle < L1MuGMTReadoutCollection >& TheL1GMTReadout,
                     edm::Handle<HBHERecHitCollection>& hbhehits,
                     edm::Handle<EcalRecHitCollection>& ecalebhits,
                     edm::Handle<EcalRecHitCollection>& ecaleehits,
                     edm::Handle<edm::TriggerResults>& TheHLTResults,
                     const edm::TriggerNames * triggerNames, 
                     const edm::Handle<CSCALCTDigiCollection>& TheALCTs,
                     MuonSegmentMatcher *TheMatcher,  
                     const edm::Event& TheEvent,
                     const edm::EventSetup& TheSetup)
{
  reco::CSCHaloData TheCSCHaloData;
  int imucount=0;
  
  bool calomatched =false;
  if(!geo){
    edm::ESHandle<CaloGeometry> pGeo;
    TheSetup.get<CaloGeometryRecord>().get(pGeo);
    geo = pGeo.product();
  }
  bool trkmuunvetoisdefault = false; //Pb with low pt tracker muons that veto good csc segments/halo triggers. 
  //Test to "unveto" low pt trk muons. 
  //For now, we just recalculate everything without the veto and add an extra set of variables to the class CSCHaloData. 
  //If this is satisfactory, these variables can become the default ones by setting trkmuunvetoisdefault to true. 
  if( TheCosmicMuons.isValid() )
    {
      short int n_tracks_small_beta=0;
      short int n_tracks_small_dT=0;
      short int n_tracks_small_dT_and_beta=0;
      for( reco::MuonCollection::const_iterator iMuon = TheCosmicMuons->begin() ; iMuon != TheCosmicMuons->end() ; iMuon++, imucount++ )
    {
      reco::TrackRef Track = iMuon->outerTrack();
      if(!Track) continue;

      bool StoreTrack = false;
      // Calculate global phi coordinate for central most rechit in the track
      float innermost_global_z = 1500.;
      float outermost_global_z = 0.;
      GlobalPoint InnerMostGlobalPosition(0.,0.,0.);  // smallest abs(z)
      GlobalPoint OuterMostGlobalPosition(0.,0.,0.);  // largest abs(z)
      int nCSCHits = 0;
      for(unsigned int j = 0 ; j < Track->extra()->recHitsSize(); j++ )
        {
          auto hit = Track->extra()->recHitRef(j);
          if( !hit->isValid() ) continue;
          DetId TheDetUnitId(hit->geographicalId());
          if( TheDetUnitId.det() != DetId::Muon ) continue;
          if( TheDetUnitId.subdetId() != MuonSubdetId::CSC ) continue;

          const GeomDetUnit *TheUnit = TheCSCGeometry.idToDetUnit(TheDetUnitId);
          LocalPoint TheLocalPosition = hit->localPosition();  
          const BoundPlane& TheSurface = TheUnit->surface();
          const GlobalPoint TheGlobalPosition = TheSurface.toGlobal(TheLocalPosition);

          float z = TheGlobalPosition.z();
          if( abs(z) < innermost_global_z )
        {
          innermost_global_z = abs(z);
          InnerMostGlobalPosition = GlobalPoint( TheGlobalPosition);
        }
          if( abs(z) > outermost_global_z )
        {
          outermost_global_z = abs(z);
          OuterMostGlobalPosition = GlobalPoint( TheGlobalPosition );
        }
          nCSCHits ++;
        }

      std::vector<const CSCSegment*> MatchedSegments = TheMatcher->matchCSC(*Track,TheEvent);
      // Find the inner and outer segments separately in case they don't agree completely with recHits
      // Plan for the possibility segments in both endcaps
      float InnerSegmentTime[2] = {0,0};
      float OuterSegmentTime[2] = {0,0};
      float innermost_seg_z[2] = {1500,1500};
      float outermost_seg_z[2] = {0,0};
      for (std::vector<const CSCSegment*>::const_iterator segment =MatchedSegments.begin();
           segment != MatchedSegments.end(); ++segment)
        {
          CSCDetId TheCSCDetId((*segment)->cscDetId());
          const CSCChamber* TheCSCChamber = TheCSCGeometry.chamber(TheCSCDetId);
          LocalPoint TheLocalPosition = (*segment)->localPosition();
          const GlobalPoint TheGlobalPosition = TheCSCChamber->toGlobal(TheLocalPosition);
          float z = TheGlobalPosition.z();
          int TheEndcap = TheCSCDetId.endcap();
          if( abs(z) < innermost_seg_z[TheEndcap-1] )
        {
          innermost_seg_z[TheEndcap-1] = abs(z);
          InnerSegmentTime[TheEndcap-1] = (*segment)->time();
        }
          if( abs(z) > outermost_seg_z[TheEndcap-1] )
        {
          outermost_seg_z[TheEndcap-1] = abs(z);
          OuterSegmentTime[TheEndcap-1] = (*segment)->time();
        }
        }

      if( nCSCHits < 3 ) continue; // This needs to be optimized, but is the minimum 

      float dT_Segment = 0; // default safe value, looks like collision muon
     
      if( innermost_seg_z[0] < outermost_seg_z[0]) // two segments in ME+
        dT_Segment =  OuterSegmentTime[0]-InnerSegmentTime[0];
      if( innermost_seg_z[1] < outermost_seg_z[1]) // two segments in ME-
        {
          // replace the measurement if there weren't segments in ME+ or
          // if the track in ME- has timing more consistent with an incoming particle
          if (dT_Segment == 0.0 ||  OuterSegmentTime[1]-InnerSegmentTime[1] < dT_Segment)
        dT_Segment = OuterSegmentTime[1]-InnerSegmentTime[1] ;
        }

      if( OuterMostGlobalPosition.x() == 0. || OuterMostGlobalPosition.y() == 0. || OuterMostGlobalPosition.z() == 0. ) 
        continue;
      if( InnerMostGlobalPosition.x() == 0. || InnerMostGlobalPosition.y() == 0. || InnerMostGlobalPosition.z() == 0. )
        continue;
      
      //Its a CSC Track,store it if it passes halo selection 
      StoreTrack = true;      

      float deta = abs( OuterMostGlobalPosition.eta() - InnerMostGlobalPosition.eta() );
      float dphi = abs(deltaPhi( OuterMostGlobalPosition.phi() , InnerMostGlobalPosition.phi() )) ;
      float theta = Track->outerMomentum().theta();
      float innermost_x = InnerMostGlobalPosition.x() ;
      float innermost_y = InnerMostGlobalPosition.y();
      float outermost_x = OuterMostGlobalPosition.x();
      float outermost_y = OuterMostGlobalPosition.y();
      float innermost_r = TMath::Sqrt(innermost_x *innermost_x + innermost_y * innermost_y );
      float outermost_r = TMath::Sqrt(outermost_x *outermost_x + outermost_y * outermost_y );
      
      if( deta < deta_threshold )
        StoreTrack = false;
      if( theta > min_outer_theta && theta < max_outer_theta )
        StoreTrack = false;
      if( dphi > dphi_threshold )
        StoreTrack = false;
      if( innermost_r < min_inner_radius )
        StoreTrack = false;
      if( innermost_r > max_inner_radius )
        StoreTrack = false;
      if( outermost_r < min_outer_radius )
        StoreTrack = false;
      if( outermost_r > max_outer_radius )
        StoreTrack  = false;
      if( Track->normalizedChi2() > norm_chi2_threshold )
        StoreTrack = false;

      if( StoreTrack )
        {
          TheCSCHaloData.GetCSCTrackImpactPositions().push_back( InnerMostGlobalPosition );
          TheCSCHaloData.GetTracks().push_back( Track );
        }

      // Analyze the MuonTimeExtra information
      if( TheCSCTimeMap.isValid() ) 
        {
          reco::MuonRef muonR(TheCosmicMuons,imucount);
          const reco::MuonTimeExtraMap & timeMapCSC = *TheCSCTimeMap;
          reco::MuonTimeExtra timecsc = timeMapCSC[muonR];
          float freeInverseBeta = timecsc.freeInverseBeta();
          
          if (dT_Segment < max_dt_muon_segment )
        n_tracks_small_dT++;
          if (freeInverseBeta < max_free_inverse_beta)
        n_tracks_small_beta++;
          if ((dT_Segment < max_dt_muon_segment) &&  (freeInverseBeta < max_free_inverse_beta))
        n_tracks_small_dT_and_beta++;
        }
      else 
           {
          static std::atomic<bool> MuonTimeFail{false};
              bool expected = false;
          if( MuonTimeFail.compare_exchange_strong(expected,true,std::memory_order_acq_rel) ) 
        {
          edm::LogWarning  ("InvalidInputTag") <<  "The MuonTimeExtraMap does not appear to be in the event. Some beam halo "
                               << " identification variables will be empty" ;
        }
        }
    }
      TheCSCHaloData.SetNIncomingTracks(n_tracks_small_dT,n_tracks_small_beta,n_tracks_small_dT_and_beta);
    }
  else // collection is invalid
    {
      static std::atomic<bool> CosmicFail{false};
      bool expected = false;
      if( CosmicFail.compare_exchange_strong(expected,true,std::memory_order_acq_rel) ) 
    {
      edm::LogWarning  ("InvalidInputTag") << " The Cosmic Muon collection does not appear to be in the event. These beam halo "
                           << " identification variables will be empty" ;
    }
    }

  if( TheHLTResults.isValid() )
    {
      bool EventPasses = false;
       for( unsigned int index = 0 ; index < vIT_HLTBit.size(); index++)
         {
           if( vIT_HLTBit[index].label().size() )
             {
               //Get the HLT bit and check to make sure it is valid 
               unsigned int bit = triggerNames->triggerIndex( vIT_HLTBit[index].label().c_str());
               if( bit < TheHLTResults->size() )
                 {
           //If any of the HLT names given by the user accept, then the event passes
           if( TheHLTResults->accept( bit ) && !TheHLTResults->error( bit ) )
             {
               EventPasses = true;
             }
                 }
             }
         }
       if( EventPasses )
         TheCSCHaloData.SetHLTBit(true);
       else
         TheCSCHaloData.SetHLTBit(false);
     }
  else //  HLT results are not valid
    {
      static std::atomic<bool> HLTFail{false};
      bool expected = false;
      if( HLTFail.compare_exchange_strong(expected,true,std::memory_order_acq_rel) ) 
    {
      edm::LogWarning  ("InvalidInputTag") << "The HLT results do not appear to be in the event. The beam halo HLT trigger "
                           << "decision will not be used in the halo identification"; 
    }
    }

   if( TheL1GMTReadout.isValid() )
     {
       L1MuGMTReadoutCollection const *gmtrc = TheL1GMTReadout.product ();
       std::vector < L1MuGMTReadoutRecord > gmt_records = gmtrc->getRecords ();
       std::vector < L1MuGMTReadoutRecord >::const_iterator igmtrr;
       
       int icsc = 0;
       int PlusZ = 0 ;
       int MinusZ = 0 ;
       int PlusZ_alt = 0 ;
       int MinusZ_alt = 0 ;

       // Check to see if CSC BeamHalo trigger is tripped
       for (igmtrr = gmt_records.begin (); igmtrr != gmt_records.end (); igmtrr++)
     {
       std::vector < L1MuRegionalCand >::const_iterator iter1;
       std::vector < L1MuRegionalCand > rmc;
       rmc = igmtrr->getCSCCands ();
       for (iter1 = rmc.begin (); iter1 != rmc.end (); iter1++)
         {
          if (!(*iter1).empty ())
        {
          if ((*iter1).isFineHalo ())
            {
              float halophi = iter1->phiValue();
              halophi = halophi > TMath::Pi() ? halophi - 2.*TMath::Pi() : halophi;
              float haloeta = iter1->etaValue();
              bool HaloIsGood = true;
              bool HaloIsGood_alt = true;
              // Check if halo trigger is faked by any collision muons
              if( TheMuons.isValid() )
            {
              float dphi = 9999.;
              float deta = 9999.;
              for( reco::MuonCollection::const_iterator mu = TheMuons->begin(); mu != TheMuons->end()  && (HaloIsGood ||!trkmuunvetoisdefault) ; mu++ )
                {
                  // Don't match with SA-only muons
                  bool lowpttrackmu =false;
                  if( mu->isStandAloneMuon() && !mu->isTrackerMuon() && !mu->isGlobalMuon() )  continue;
                  if( !mu->isGlobalMuon() &&  mu->isTrackerMuon() &&  mu->pt()<3 && trkmuunvetoisdefault) continue;
                  if( !mu->isGlobalMuon() &&  mu->isTrackerMuon() &&  mu->pt()<3 ) lowpttrackmu = true;

                  /*
                  if(!mu->isTrackerMuon())
                {
                  if( mu->isStandAloneMuon() )
                    {
                      //make sure that this SA muon is not actually a halo-like muon
                      float theta =  mu->outerTrack()->outerMomentum().theta();
                      float deta = abs(mu->outerTrack()->outerPosition().eta() - mu->outerTrack()->innerPosition().eta());
                      if( theta < min_outer_theta || theta > max_outer_theta )  //halo-like
                    continue;
                      else if ( deta > deta_threshold ) //halo-like
                    continue;
                    }
                }
                  */
                
                  const std::vector<MuonChamberMatch> chambers = mu->matches();
                  for(std::vector<MuonChamberMatch>::const_iterator iChamber = chambers.begin();
                  iChamber != chambers.end() ; iChamber ++ )
                {
                  if( iChamber->detector() != MuonSubdetId::CSC ) continue;
                  for( std::vector<reco::MuonSegmentMatch>::const_iterator iSegment = iChamber->segmentMatches.begin() ; 
                       iSegment != iChamber->segmentMatches.end(); ++iSegment )
                    {
                      edm::Ref<CSCSegmentCollection> cscSegment = iSegment->cscSegmentRef;
                      std::vector<CSCRecHit2D> hits = cscSegment -> specificRecHits();
                      for( std::vector<CSCRecHit2D>::iterator iHit = hits.begin();
                       iHit != hits.end() ; iHit++ )
                    {
                      DetId TheDetUnitId(iHit->cscDetId());
                      const GeomDetUnit *TheUnit = TheCSCGeometry.idToDetUnit(TheDetUnitId);
                      LocalPoint TheLocalPosition = iHit->localPosition();
                      const BoundPlane& TheSurface = TheUnit->surface();
                      GlobalPoint TheGlobalPosition = TheSurface.toGlobal(TheLocalPosition);
                      
                      float phi_ = TheGlobalPosition.phi();
                      float eta_ = TheGlobalPosition.eta();
                      
                      deta = deta < abs( eta_ - haloeta ) ? deta : abs( eta_ - haloeta );
                      dphi = dphi < abs(deltaPhi(phi_, halophi)) ? dphi : abs(deltaPhi(phi_, halophi));
                    }
                    }
                }
                  if ( dphi < matching_dphi_threshold && deta < matching_deta_threshold){ 
                HaloIsGood = false; // i.e., collision muon likely faked halo trigger
                if(!lowpttrackmu)HaloIsGood_alt   = false;
                  }
                }
            }
              if( HaloIsGood ){ 
            if( (*iter1).etaValue() > 0 )
              PlusZ++;
            else
              MinusZ++;
              }
              if( HaloIsGood_alt ){
            if( (*iter1).etaValue() > 0 )
                          PlusZ_alt++;
                        else
                          MinusZ_alt++;
                      }

            }
          else
            icsc++;
        }
         }
     }
       TheCSCHaloData.SetNumberOfHaloTriggers(PlusZ, MinusZ);
       TheCSCHaloData.SetNumberOfHaloTriggers_TrkMuUnVeto(PlusZ_alt, MinusZ_alt);
     }
   else
     {
       static std::atomic<bool> L1Fail{false};   
       bool expected = false;
       if( L1Fail.compare_exchange_strong(expected,true,std::memory_order_acq_rel) ) 
     {
       edm::LogWarning  ("InvalidInputTag") << "The L1MuGMTReadoutCollection does not appear to be in the event. The L1 beam halo trigger "
                        << "decision will not be used in the halo identification"; 
     }
     }

   // Loop over CSCALCTDigi collection to look for out-of-time chamber triggers 
   // A collision muon in real data should only have ALCTDigi::getBX() = 3 ( in MC, it will be 6 )
   // Note that there could be two ALCTs per chamber 
   short int n_alctsP=0;
   short int n_alctsM=0;
   if(TheALCTs.isValid())
     {
       for (CSCALCTDigiCollection::DigiRangeIterator j=TheALCTs->begin(); j!=TheALCTs->end(); j++) 
     {
       const CSCALCTDigiCollection::Range& range =(*j).second;
       CSCDetId detId((*j).first.rawId());
       for (CSCALCTDigiCollection::const_iterator digiIt = range.first; digiIt!=range.second; ++digiIt)
         {
           if( (*digiIt).isValid() && ( (*digiIt).getBX() < expected_BX ) )
         {
           int digi_endcap  = detId.endcap();
           int digi_station = detId.station();
           int digi_ring    = detId.ring();
           int digi_chamber = detId.chamber();
           int digi_wire    = digiIt->getKeyWG();
           if( digi_station == 1 && digi_ring == 4 )   //hack
             digi_ring = 1;
           
           bool DigiIsGood = true;
           int dwire = 999.;
           if( TheMuons.isValid() ) 
             {
               //Check if there are any collision muons with hits in the vicinity of the digi
               for(reco::MuonCollection::const_iterator mu = TheMuons->begin(); mu!= TheMuons->end() && DigiIsGood ; mu++ )
             {
               
               if( !mu->isTrackerMuon() && !mu->isGlobalMuon() && mu->isStandAloneMuon() ) continue;
               if( !mu->isGlobalMuon() &&  mu->isTrackerMuon() &&  mu->pt()<3 &&trkmuunvetoisdefault) continue;
               const std::vector<MuonChamberMatch> chambers = mu->matches();
               for(std::vector<MuonChamberMatch>::const_iterator iChamber = chambers.begin();
                   iChamber != chambers.end(); iChamber ++ )
                 {
                   if( iChamber->detector() != MuonSubdetId::CSC ) continue;
                   for( std::vector<reco::MuonSegmentMatch>::const_iterator iSegment = iChamber->segmentMatches.begin();
                    iSegment != iChamber->segmentMatches.end(); iSegment++ )
                 {
                   edm::Ref<CSCSegmentCollection> cscSegRef = iSegment->cscSegmentRef;
                   std::vector<CSCRecHit2D> hits = cscSegRef->specificRecHits();
                   for( std::vector<CSCRecHit2D>::iterator iHit = hits.begin();
                    iHit != hits.end(); iHit++ )
                     {
                       if( iHit->cscDetId().endcap() != digi_endcap ) continue;
                       if( iHit->cscDetId().station() != digi_station ) continue;
                       if( iHit->cscDetId().ring() != digi_ring ) continue;
                       if( iHit->cscDetId().chamber() != digi_chamber ) continue;
                       int hit_wire = iHit->hitWire();
                       dwire = dwire < abs(hit_wire - digi_wire)? dwire : abs(hit_wire - digi_wire );
                     }
                 }
                 }
               if( dwire <= matching_dwire_threshold ) 
                 DigiIsGood = false;  // collision-like muon is close to this digi
             }
             }
           // only count out of time digis if they are not matched to collision muons
           if( DigiIsGood ) 
             {
               if( detId.endcap() == 1 ) 
             n_alctsP++;
               else if ( detId.endcap() ==  2) 
             n_alctsM++;
             }
         }
         }
     }
     }
   else
     {
       static std::atomic<bool> DigiFail{false};
       bool expected = false;
       if (DigiFail.compare_exchange_strong(expected,true,std::memory_order_acq_rel)){
     edm::LogWarning  ("InvalidInputTag") << "The CSCALCTDigiCollection does not appear to be in the event. The ALCT Digis will "
                          << " not be used in the halo identification"; 
       }
     }
   TheCSCHaloData.SetNOutOfTimeTriggers(n_alctsP,n_alctsM);

   // Loop over the CSCRecHit2D collection to look for out-of-time recHits
   // Out-of-time is defined as tpeak outside [t_0 + TOF - t_window, t_0 + TOF + t_window]
   // where t_0 and t_window are configurable parameters
   short int n_recHitsP = 0;
   short int n_recHitsM = 0;
   if( TheCSCRecHits.isValid() )
     {
       CSCRecHit2DCollection::const_iterator dRHIter;
       for (dRHIter = TheCSCRecHits->begin(); dRHIter != TheCSCRecHits->end(); dRHIter++) 
     {
       if ( !((*dRHIter).isValid()) ) continue;  // only interested in valid hits
       CSCDetId idrec = (CSCDetId)(*dRHIter).cscDetId();
       float RHTime = (*dRHIter).tpeak();
       LocalPoint rhitlocal = (*dRHIter).localPosition();
       const CSCChamber* chamber = TheCSCGeometry.chamber(idrec);
       GlobalPoint globalPosition = chamber->toGlobal(rhitlocal);
       float globZ = globalPosition.z();
       if ( RHTime < (recHit_t0 - recHit_twindow) )
         {
           if( globZ > 0 )
         n_recHitsP++;
           else
         n_recHitsM++;
         }
       
       /*

       float globX = globalPosition.x();
       float globY = globalPosition.y();
       float globZ = globalPosition.z();
       float TOF = (sqrt(globX*globX+ globY*globY + globZ*globZ))/29.9792458 ; //cm -> ns
       if ( (RHTime < (recHit_t0 + TOF - recHit_twindow)) || (RHTime > (recHit_t0 + TOF + recHit_twindow)) )
         {
           if( globZ > 0 ) 
         n_recHitsP++;
           else
         n_recHitsM++;
         }
       */
     }
     }
   else
     {
       static std::atomic<bool> RecHitFail{false};
       bool expected = false;
       if( RecHitFail.compare_exchange_strong(expected,true,std::memory_order_acq_rel)  ) 
     {
       edm::LogWarning  ("InvalidInputTag") << "The requested CSCRecHit2DCollection does not appear to be in the event. The CSC RecHit "
                        << " variables used for halo identification will not be calculated or stored";
     }       
     }
   TheCSCHaloData.SetNOutOfTimeHits(n_recHitsP+n_recHitsM);
   // MLR
   // Loop through CSCSegments and count the number of "flat" segments with the same (r,phi),
   // saving the value in TheCSCHaloData.
   short int maxNSegments = 0;
   bool plus_endcap = false;
   bool minus_endcap = false;
   bool both_endcaps = false;
   bool both_endcaps_loose = false;
   //   bool both_endcaps_dtcut = false;

   short int maxNSegments_alt = 0;
   bool both_endcaps_alt = false;
   bool both_endcaps_loose_alt = false;
   bool both_endcaps_loose_dtcut_alt = false;

   //float r = 0., phi = 0.;
   if (TheCSCSegments.isValid()) {
     for(CSCSegmentCollection::const_iterator iSegment = TheCSCSegments->begin();
         iSegment != TheCSCSegments->end();
         iSegment++) {

       CSCDetId iCscDetID = iSegment->cscDetId();
       bool Segment1IsGood=true;
       bool Segment1IsGood_alt=true;

       //avoid segments from collision muons
       if( TheMuons.isValid() )
     {
       for(reco::MuonCollection::const_iterator mu = TheMuons->begin(); mu!= TheMuons->end() && (Segment1IsGood||!trkmuunvetoisdefault)   ; mu++ )
         {
           bool  lowpttrackmu=false;
           if( !mu->isTrackerMuon() && !mu->isGlobalMuon() && mu->isStandAloneMuon() ) continue;
           if( !mu->isTrackerMuon() && !mu->isGlobalMuon() && mu->isStandAloneMuon()&&trkmuunvetoisdefault) continue;
           if( !mu->isGlobalMuon() &&  mu->isTrackerMuon() &&  mu->pt()<3) lowpttrackmu=true;
           const std::vector<MuonChamberMatch> chambers = mu->matches();
           for(std::vector<MuonChamberMatch>::const_iterator kChamber = chambers.begin();
           kChamber != chambers.end(); kChamber ++ )
         {
           if( kChamber->detector() != MuonSubdetId::CSC ) continue;
           for( std::vector<reco::MuonSegmentMatch>::const_iterator kSegment = kChamber->segmentMatches.begin();
            kSegment != kChamber->segmentMatches.end(); kSegment++ )
             {
               edm::Ref<CSCSegmentCollection> cscSegRef = kSegment->cscSegmentRef;
               CSCDetId kCscDetID = cscSegRef->cscDetId();
               
               if( kCscDetID == iCscDetID ) 
             {
               Segment1IsGood = false;
               if(!lowpttrackmu) Segment1IsGood_alt=false;
             }
             }
         }
         }
     }
       if(!Segment1IsGood&&!Segment1IsGood_alt) continue;
       
       // Get local direction vector; if direction runs parallel to beamline,
       // count this segment as beam halo candidate.
       LocalPoint iLocalPosition = iSegment->localPosition();
       LocalVector iLocalDirection = iSegment->localDirection();

       GlobalPoint iGlobalPosition = TheCSCGeometry.chamber(iCscDetID)->toGlobal(iLocalPosition);
       GlobalVector iGlobalDirection = TheCSCGeometry.chamber(iCscDetID)->toGlobal(iLocalDirection);

       float iTheta = iGlobalDirection.theta();
       if (iTheta > max_segment_theta && iTheta < TMath::Pi() - max_segment_theta) continue;
       
       float iPhi = iGlobalPosition.phi();
       float iR =  TMath::Sqrt(iGlobalPosition.x()*iGlobalPosition.x() + iGlobalPosition.y()*iGlobalPosition.y());
       float iZ = iGlobalPosition.z();
       float iT = iSegment->time();
       //Timing condition, helps removing random segments from next collisions
       if(iT>15) continue;
       //Calo matching:

       bool hbhematched = HCALSegmentMatching(hbhehits,et_thresh_rh_hbhe,dphi_thresh_segvsrh_hbhe,dr_lowthresh_segvsrh_hbhe,dr_highthresh_segvsrh_hbhe,dt_lowthresh_segvsrh_hbhe,dt_highthresh_segvsrh_hbhe,iZ,iR,iT,iPhi);
       bool ebmatched = ECALSegmentMatching(ecalebhits,et_thresh_rh_eb,dphi_thresh_segvsrh_eb,dr_lowthresh_segvsrh_eb,dr_highthresh_segvsrh_eb,dt_lowthresh_segvsrh_eb,dt_highthresh_segvsrh_eb,iZ,iR,iT,iPhi);
       bool eematched = ECALSegmentMatching(ecaleehits,et_thresh_rh_ee,dphi_thresh_segvsrh_ee,dr_lowthresh_segvsrh_ee,dr_highthresh_segvsrh_ee,dt_lowthresh_segvsrh_ee,dt_highthresh_segvsrh_ee,iZ,iR,iT,iPhi); 
       calomatched = calomatched? true: (hbhematched|| ebmatched|| eematched);


       short int nSegs = 0;
       short int nSegs_alt = 0;
       // Changed to loop over all Segments (so N^2) to catch as many segments as possible.
       for (CSCSegmentCollection::const_iterator jSegment = TheCSCSegments->begin();
         jSegment != TheCSCSegments->end();
         jSegment++) {
     if (jSegment == iSegment) continue;
     bool Segment2IsGood = true;
     bool Segment2IsGood_alt = true;
     LocalPoint jLocalPosition = jSegment->localPosition();
     LocalVector jLocalDirection = jSegment->localDirection();
     CSCDetId jCscDetID = jSegment->cscDetId();
     GlobalPoint jGlobalPosition = TheCSCGeometry.chamber(jCscDetID)->toGlobal(jLocalPosition);
     GlobalVector jGlobalDirection = TheCSCGeometry.chamber(jCscDetID)->toGlobal(jLocalDirection);
     float jTheta = jGlobalDirection.theta();
     float jPhi = jGlobalPosition.phi();
     float jR =  TMath::Sqrt(jGlobalPosition.x()*jGlobalPosition.x() + jGlobalPosition.y()*jGlobalPosition.y());
     float jZ = jGlobalPosition.z() ;
     float jT = jSegment->time();
     //Timing condition, helps removing random segments from next collisions
     if(jT>15) continue;
     //  if(abs(jZ)<650&& TheEvent.id().run() < 251737)jT-= 25;
     if (abs(deltaPhi(jPhi , iPhi))<=0.1//max_segment_phi_diff 
         //&& abs(jR - iR) <= max_segment_r_diff 
         && (abs(jR - iR)<0.03*abs(jZ - iZ)) 
         && (abs(jR - iR) <= max_segment_r_diff ||  jZ*iZ < 0) 
         && (jTheta < max_segment_theta || jTheta > TMath::Pi() - max_segment_theta)
         ) {
       if( TheMuons.isValid() ) {
         for(reco::MuonCollection::const_iterator mu = TheMuons->begin(); mu!= TheMuons->end()  && (Segment2IsGood||!trkmuunvetoisdefault) ; mu++ ) {
           bool  lowpttrackmu=false;
           if( !mu->isTrackerMuon() && !mu->isGlobalMuon() && mu->isStandAloneMuon() ) continue;
           if( !mu->isGlobalMuon() &&  mu->isTrackerMuon() &&  mu->pt()<3) lowpttrackmu= true;
           const std::vector<MuonChamberMatch> chambers = mu->matches();
           for(std::vector<MuonChamberMatch>::const_iterator kChamber = chambers.begin();
           kChamber != chambers.end(); kChamber ++ ) {
         if( kChamber->detector() != MuonSubdetId::CSC ) continue;
         for( std::vector<reco::MuonSegmentMatch>::const_iterator kSegment = kChamber->segmentMatches.begin();
              kSegment != kChamber->segmentMatches.end(); kSegment++ ) {
           edm::Ref<CSCSegmentCollection> cscSegRef = kSegment->cscSegmentRef;
           CSCDetId kCscDetID = cscSegRef->cscDetId();
           
           if( kCscDetID == jCscDetID ) {
             Segment2IsGood = false;
             if(!lowpttrackmu) Segment2IsGood_alt=false;
           }
         }
           }
         }
       }   
       if(Segment1IsGood && Segment2IsGood) {
         nSegs++;
         minus_endcap = iGlobalPosition.z() < 0 || jGlobalPosition.z() < 0;
         plus_endcap = iGlobalPosition.z() > 0 || jGlobalPosition.z() > 0;
         //      if( abs(jT-iT)/sqrt( (jR-iR)*(jR-iR)+(jZ-iZ)*(jZ-iZ) )<0.05 && abs(jT-iT)/sqrt( (jR-iR)*(jR-iR)+(jZ-iZ)*(jZ-iZ) )>0.02 && minus_endcap&&plus_endcap ) both_endcaps_dtcut =true;
       }
       if(Segment1IsGood_alt && Segment2IsGood_alt) {
             nSegs_alt++;
             minus_endcap = iGlobalPosition.z() < 0 || jGlobalPosition.z() < 0;
             plus_endcap = iGlobalPosition.z() > 0 || jGlobalPosition.z() > 0;
             if( 
        abs(jT-iT)<0.05*sqrt( (jR-iR)*(jR-iR)+(jZ-iZ)*(jZ-iZ) ) && 
        abs(jT-iT)> 0.02*sqrt( (jR-iR)*(jR-iR)+(jZ-iZ)*(jZ-iZ) ) && 
        (iT>-15 || jT>-15)&&
        minus_endcap&&plus_endcap ) both_endcaps_loose_dtcut_alt =true;
           }
       
     }
       }
       // Correct the fact that the way nSegs counts will always be short by 1
       if (nSegs > 0) nSegs++;
       
       // The opposite endcaps segments do not need to belong to the longest chain. 
       if (nSegs > 0) both_endcaps_loose =  both_endcaps_loose ? both_endcaps_loose : minus_endcap && plus_endcap;
       if (nSegs_alt > 0) nSegs_alt++;
       if (nSegs_alt > 0) both_endcaps_loose_alt =  both_endcaps_loose_alt ? both_endcaps_loose_alt : minus_endcap && plus_endcap;

       //       if (nSegs > 0) both_endcaps_dt20ns = both_endcaps_dt20ns ? both_endcaps_dt20ns : minus_endcap && plus_endcap &&dt20ns;
       if (nSegs > maxNSegments) {
     // Use value of r, phi to collect halo CSCSegments for examining timing (not coded yet...)
     //r = iR;
     //phi = iPhi;
     maxNSegments = nSegs;
     both_endcaps = both_endcaps ? both_endcaps : minus_endcap && plus_endcap;
       }
      
       if (nSegs_alt > maxNSegments_alt) {
         maxNSegments_alt = nSegs_alt;
         both_endcaps_alt = both_endcaps_alt ? both_endcaps_alt : minus_endcap && plus_endcap;
       }
 
     }
   }
   TheCSCHaloData.SetNFlatHaloSegments(maxNSegments);
   TheCSCHaloData.SetSegmentsBothEndcaps(both_endcaps);
   TheCSCHaloData.SetNFlatHaloSegments_TrkMuUnVeto(maxNSegments_alt);
   TheCSCHaloData.SetSegmentsBothEndcaps_Loose_TrkMuUnVeto(both_endcaps_loose_alt);
   TheCSCHaloData.SetSegmentsBothEndcaps_Loose_dTcut_TrkMuUnVeto(both_endcaps_loose_dtcut_alt);
   TheCSCHaloData.SetSegmentIsCaloMatched(calomatched);

   return TheCSCHaloData;
}

math::XYZPoint CSCHaloAlgo::getPosition(const DetId &id, reco::Vertex::Point vtx){

  const GlobalPoint& pos=geo->getPosition(id);
  math::XYZPoint posV(pos.x() - vtx.x(),pos.y() - vtx.y(),pos.z() - vtx.z());
  return posV;
}


bool CSCHaloAlgo::HCALSegmentMatching(edm::Handle<HBHERecHitCollection>& rechitcoll, float et_thresh_rh, float dphi_thresh_segvsrh, float dr_lowthresh_segvsrh, float dr_highthresh_segvsrh, float dt_lowthresh_segvsrh , float dt_highthresh_segvsrh , float iZ, float iR, float iT, float iPhi){
  reco::Vertex::Point vtx(0,0,0);
  for(size_t ihit = 0; ihit< rechitcoll->size(); ++ ihit){
    const HBHERecHit & rechit = (*rechitcoll)[ ihit ];
    math::XYZPoint rhpos = getPosition(rechit.id(),vtx);
    double rhet = rechit.energy()/cosh(rhpos.eta());
    double dphi_rhseg = abs(deltaPhi(rhpos.phi(),iPhi));
    double dr_rhseg = sqrt(rhpos.x()*rhpos.x()+rhpos.y()*rhpos.y()) - iR;
    double dtcorr_rhseg = rechit.time()- abs(rhpos.z()-iZ)/30- iT; 
    if(
       ( rechit.time()<-3)&&
       (rhpos.z()*iZ<0|| abs(rhpos.z())<200)&&
       rhet> et_thresh_rh&&
       dphi_rhseg < dphi_thresh_segvsrh &&
       dr_rhseg < dr_highthresh_segvsrh && dr_rhseg> dr_lowthresh_segvsrh && //careful: asymmetric cut might not be the most appropriate thing 
       dtcorr_rhseg> dt_lowthresh_segvsrh && dtcorr_rhseg< dt_highthresh_segvsrh
      ) return true; 
  }
  return false;
}

bool CSCHaloAlgo::ECALSegmentMatching(edm::Handle<EcalRecHitCollection>& rechitcoll,  float et_thresh_rh, float dphi_thresh_segvsrh, float dr_lowthresh_segvsrh, float dr_highthresh_segvsrh, float dt_lowthresh_segvsrh,float dt_highthresh_segvsrh, float iZ, float iR, float iT, float iPhi ){
  reco::Vertex::Point vtx(0,0,0);
  for(size_t ihit = 0; ihit<rechitcoll->size(); ++ ihit){
    const EcalRecHit & rechit = (*rechitcoll)[ ihit ];
    math::XYZPoint rhpos = getPosition(rechit.id(),vtx);
    double rhet = rechit.energy()/cosh(rhpos.eta());
    double dphi_rhseg = abs(deltaPhi(rhpos.phi(),iPhi));
    double dr_rhseg = sqrt(rhpos.x()*rhpos.x()+rhpos.y()*rhpos.y()) - iR;
    double dtcorr_rhseg = rechit.time()- abs(rhpos.z()-iZ)/30- iT; 
    if( 
       ( rechit.time()<-1)&&
       (rhpos.z()*iZ<0|| abs(rhpos.z())<200)&&
       rhet> et_thresh_rh&&
       dphi_rhseg < dphi_thresh_segvsrh &&
       dr_rhseg < dr_highthresh_segvsrh && dr_rhseg> dr_lowthresh_segvsrh && //careful: asymmetric cut might not be the most appropriate thing 
       dtcorr_rhseg> dt_lowthresh_segvsrh && dtcorr_rhseg< dr_highthresh_segvsrh
       ) return true; 
  }
  return false;
}