CSCTimingExtractor Class Reference

#include <RecoMuon/MuonIdentification/src/CSCTimingExtractor.cc>

Classes
class	TimeMeasurement

Public Member Functions
	CSCTimingExtractor (const edm::ParameterSet &, MuonSegmentMatcher *segMatcher)
	Constructor. More...
void	fillTiming (TimeMeasurementSequence &tmSequence, reco::TrackRef muonTrack, const edm::Event &iEvent, const edm::EventSetup &iSetup)
	~CSCTimingExtractor ()
	Destructor. More...

Private Attributes
edm::InputTag	CSCSegmentTags_
bool	debug
unsigned int	theHitsMin_
MuonSegmentMatcher *	theMatcher
double	thePruneCut_
std::unique_ptr< MuonServiceProxy >	theService
double	theStripError_
double	theStripTimeOffset_
double	theWireError_
double	theWireTimeOffset_
bool	UseStripTime
bool	UseWireTime

Detailed Description

Extracts timing information associated to a muon track

Description: Produce timing information for a muon track using CSC hits from segments used to build the track

Definition at line 54 of file CSCTimingExtractor.h.

Constructor & Destructor Documentation

CSCTimingExtractor::CSCTimingExtractor	(	const edm::ParameterSet &	iConfig,
		MuonSegmentMatcher *	segMatcher
	)

Constructor.

Definition at line 69 of file CSCTimingExtractor.cc.

References edm::ParameterSet::getParameter(), theMatcher, and theService.

  :
  thePruneCut_(iConfig.getParameter<double>("PruneCut")),
  theStripTimeOffset_(iConfig.getParameter<double>("CSCStripTimeOffset")),
  theWireTimeOffset_(iConfig.getParameter<double>("CSCWireTimeOffset")),
  theStripError_(iConfig.getParameter<double>("CSCStripError")),
  theWireError_(iConfig.getParameter<double>("CSCWireError")),
  UseWireTime(iConfig.getParameter<bool>("UseWireTime")),
  UseStripTime(iConfig.getParameter<bool>("UseStripTime")),
  debug(iConfig.getParameter<bool>("debug"))
{
  edm::ParameterSet serviceParameters = iConfig.getParameter<edm::ParameterSet>("ServiceParameters");
  theService = std::make_unique<MuonServiceProxy>(serviceParameters);
  theMatcher = segMatcher;
}

CSCTimingExtractor::~CSCTimingExtractor

(

)

Destructor.

Definition at line 86 of file CSCTimingExtractor.cc.

{
}

Member Function Documentation

void CSCTimingExtractor::fillTiming	(	TimeMeasurementSequence &	tmSequence,
		reco::TrackRef	muonTrack,
		const edm::Event &	iEvent,
		const edm::EventSetup &	iSetup
	)

Definition at line 97 of file CSCTimingExtractor.cc.

References gather_cfg::cout, debug, CSCTimingExtractor::TimeMeasurement::distIP, TimeMeasurementSequence::dstnc, edm::EventSetup::get(), i, GlobalTrackingGeometry::idToDet(), TimeMeasurementSequence::local_t0, mag(), MuonSegmentMatcher::matchCSC(), edm::ESHandle< class >::product(), Propagator::propagateWithPath(), HLT_FULL_cff::propagator, mathSSE::sqrt(), GeomDet::surface(), theMatcher, thePruneCut_, theService, theStripError_, theStripTimeOffset_, MuonServiceProxy::theTrackingGeometry, theWireError_, theWireTimeOffset_, CSCTimingExtractor::TimeMeasurement::timeCorr, GeomDet::toGlobal(), TimeMeasurementSequence::totalWeightInvbeta, TimeMeasurementSequence::totalWeightTimeVtx, UseStripTime, UseWireTime, TimeMeasurementSequence::weightInvbeta, CSCTimingExtractor::TimeMeasurement::weightInvbeta, TimeMeasurementSequence::weightTimeVtx, and CSCTimingExtractor::TimeMeasurement::weightTimeVtx.

{

  if (debug) 
    std::cout << " *** CSC Timimng Extractor ***" << std::endl;

  theService->update(iSetup);

  const GlobalTrackingGeometry *theTrackingGeometry = &*theService->trackingGeometry();

  // get the propagator  
  edm::ESHandle<Propagator> propagator;
  iSetup.get<TrackingComponentsRecord>().get("SteppingHelixPropagatorAny", propagator);
  const Propagator *propag = propagator.product();

  math::XYZPoint  pos=muonTrack->innerPosition();
  math::XYZVector mom=muonTrack->innerMomentum();
  if (sqrt(muonTrack->innerPosition().mag2()) > sqrt(muonTrack->outerPosition().mag2())){
     pos=muonTrack->outerPosition();
     mom=-1*muonTrack->outerMomentum();
  }
  GlobalPoint  posp(pos.x(), pos.y(), pos.z());
  GlobalVector momv(mom.x(), mom.y(), mom.z());
  FreeTrajectoryState muonFTS(posp, momv, (TrackCharge)muonTrack->charge(), theService->magneticField().product());

  // get the CSC segments that were used to construct the muon
  std::vector<const CSCSegment*> range = theMatcher->matchCSC(*muonTrack,iEvent);

  // create a collection on TimeMeasurements for the track        
  std::vector<TimeMeasurement> tms;
  for (std::vector<const CSCSegment*>::iterator rechit = range.begin(); rechit!=range.end();++rechit) {

    // Create the ChamberId
    DetId id = (*rechit)->geographicalId();
    CSCDetId chamberId(id.rawId());
    //    int station = chamberId.station();

    if (!(*rechit)->specificRecHits().size()) continue;

    const std::vector<CSCRecHit2D> hits2d = (*rechit)->specificRecHits();

    // store all the hits from the segment
    for (std::vector<CSCRecHit2D>::const_iterator hiti=hits2d.begin(); hiti!=hits2d.end(); hiti++) {

      const GeomDet* cscDet = theTrackingGeometry->idToDet(hiti->geographicalId());
      TimeMeasurement thisHit;

      std::pair< TrajectoryStateOnSurface, double> tsos;
      tsos=propag->propagateWithPath(muonFTS,cscDet->surface());

      double dist;            
      if (tsos.first.isValid()) dist = tsos.second+posp.mag(); 
        else dist = cscDet->toGlobal(hiti->localPosition()).mag();

      thisHit.distIP = dist;
      if (UseStripTime) {
        thisHit.weightInvbeta = dist*dist/(theStripError_*theStripError_*30.*30.);
        thisHit.weightTimeVtx = 1./(theStripError_*theStripError_);
        thisHit.timeCorr = hiti->tpeak()-theStripTimeOffset_;
        tms.push_back(thisHit);
      }

      if (UseWireTime) {
    thisHit.weightInvbeta = dist*dist/(theWireError_*theWireError_*30.*30.);
        thisHit.weightTimeVtx = 1./(theWireError_*theWireError_);
        thisHit.timeCorr = hiti->wireTime()-theWireTimeOffset_;
        tms.push_back(thisHit);
      }
      
//      std::cout << " CSC Hit. Dist= " << dist << "    Time= " << thisHit.timeCorr 
//           << "   invBeta= " << (1.+thisHit.timeCorr/dist*30.) << std::endl;
    }

  } // rechit

  bool modified = false;
  std::vector <double> dstnc, local_t0, hitWeightInvbeta, hitWeightTimeVtx;
  double totalWeightInvbeta=0;
  double totalWeightTimeVtx=0;

  // Now loop over the measurements, calculate 1/beta and cut away outliers
  do {    

    modified = false;
    dstnc.clear();
    local_t0.clear();
    hitWeightInvbeta.clear();
    hitWeightTimeVtx.clear();

    totalWeightInvbeta=0;
    totalWeightTimeVtx=0;
      
    for (std::vector<TimeMeasurement>::iterator tm=tms.begin(); tm!=tms.end(); ++tm) {
      dstnc.push_back(tm->distIP);
      local_t0.push_back(tm->timeCorr);
      hitWeightInvbeta.push_back(tm->weightInvbeta);
      hitWeightTimeVtx.push_back(tm->weightTimeVtx);
      totalWeightInvbeta+=tm->weightInvbeta;
      totalWeightTimeVtx+=tm->weightTimeVtx;
    }
          
    if (totalWeightInvbeta==0) break;        

    // calculate the value and error of 1/beta and timeVtx from the complete set of 1D hits
    if (debug)
      std::cout << " Points for global fit: " << dstnc.size() << std::endl;

    double invbeta=0,invbetaErr=0;
    double timeVtx=0,timeVtxErr=0;

    for (unsigned int i=0;i<dstnc.size();i++) {
      invbeta+=(1.+local_t0.at(i)/dstnc.at(i)*30.)*hitWeightInvbeta.at(i)/totalWeightInvbeta;
      timeVtx+=local_t0.at(i)*hitWeightTimeVtx.at(i)/totalWeightTimeVtx;
    }
    
    double chimax=0.;
    std::vector<TimeMeasurement>::iterator tmmax;
    
    // Calculate the inv beta and time at vertex dispersion
    double diff_ibeta,diff_tvtx;
    for (unsigned int i=0;i<dstnc.size();i++) {
      diff_ibeta=(1.+local_t0.at(i)/dstnc.at(i)*30.)-invbeta;
      diff_ibeta=diff_ibeta*diff_ibeta*hitWeightInvbeta.at(i);
      diff_tvtx=local_t0.at(i)-timeVtx;
      diff_tvtx=diff_tvtx*diff_tvtx*hitWeightTimeVtx.at(i);
      invbetaErr+=diff_ibeta;
      timeVtxErr+=diff_tvtx;
      
      // decide if we cut away time at vertex outliers or inverse beta outliers
      // currently not configurable.
      if (diff_tvtx>chimax) { 
    tmmax=tms.begin()+i;
    chimax=diff_tvtx;
      }
    }
    
    // cut away the outliers
    if (chimax>thePruneCut_) {
      tms.erase(tmmax);
      modified=true;
    }    

    if (debug) {
      double cf = 1./(dstnc.size()-1);
      invbetaErr=sqrt(invbetaErr/totalWeightInvbeta*cf); 
      timeVtxErr=sqrt(timeVtxErr/totalWeightTimeVtx*cf); 
      std::cout << " Measured 1/beta: " << invbeta << " +/- " << invbetaErr << std::endl;
      std::cout << " Measured time: " << timeVtx << " +/- " << timeVtxErr << std::endl;
    }  

  } while (modified);

  for (unsigned int i=0;i<dstnc.size();i++) {
    tmSequence.dstnc.push_back(dstnc.at(i));
    tmSequence.local_t0.push_back(local_t0.at(i));
    tmSequence.weightInvbeta.push_back(hitWeightInvbeta.at(i));
    tmSequence.weightTimeVtx.push_back(hitWeightTimeVtx.at(i));
  }

  tmSequence.totalWeightInvbeta=totalWeightInvbeta;
  tmSequence.totalWeightTimeVtx=totalWeightTimeVtx;

}

Member Data Documentation

edm::InputTag CSCTimingExtractor::CSCSegmentTags_

private

Definition at line 78 of file CSCTimingExtractor.h.

bool CSCTimingExtractor::debug

private

Definition at line 87 of file CSCTimingExtractor.h.

Referenced by fillTiming().

unsigned int CSCTimingExtractor::theHitsMin_

private

Definition at line 79 of file CSCTimingExtractor.h.

MuonSegmentMatcher* CSCTimingExtractor::theMatcher

private

Definition at line 90 of file CSCTimingExtractor.h.

Referenced by CSCTimingExtractor(), and fillTiming().

double CSCTimingExtractor::thePruneCut_

private

Definition at line 80 of file CSCTimingExtractor.h.

Referenced by fillTiming().

std::unique_ptr<MuonServiceProxy> CSCTimingExtractor::theService

private

Definition at line 89 of file CSCTimingExtractor.h.

Referenced by CSCTimingExtractor(), and fillTiming().

double CSCTimingExtractor::theStripError_

private

Definition at line 83 of file CSCTimingExtractor.h.

Referenced by fillTiming().

double CSCTimingExtractor::theStripTimeOffset_

private

Definition at line 81 of file CSCTimingExtractor.h.

Referenced by fillTiming().

double CSCTimingExtractor::theWireError_

private

Definition at line 84 of file CSCTimingExtractor.h.

Referenced by fillTiming().

double CSCTimingExtractor::theWireTimeOffset_

private

Definition at line 82 of file CSCTimingExtractor.h.

Referenced by fillTiming().

bool CSCTimingExtractor::UseStripTime

private

Definition at line 86 of file CSCTimingExtractor.h.

Referenced by fillTiming().

bool CSCTimingExtractor::UseWireTime

private

Definition at line 85 of file CSCTimingExtractor.h.

Referenced by fillTiming().