ThirdHitCorrection.cc

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#include "ThirdHitCorrection.h"

#include "RecoTracker/TkMSParametrization/interface/LongitudinalBendingCorrection.h"
#include "RecoTracker/TkMSParametrization/interface/MultipleScatteringParametrisation.h"

using namespace pixelrecoutilities;

namespace {
  template <class T> inline T sqr( T t) {return t*t;}
}

//namespace pixelrecoutilities { class LongitudinalBendingCorrection; }
//class MultipleScatteringParametrisation;
//  const MultipleScatteringParametrisation * theScattering;
//  const pixelrecoutilities::LongitudinalBendingCorrection * theBenging;

using pixelrecoutilities::LongitudinalBendingCorrection;

void ThirdHitCorrection::init(const edm::EventSetup& es, 
             float pt,
             const DetLayer * layer,
             const PixelRecoLineRZ & line,
             const PixelRecoPointRZ & constraint,
             bool useMultipleScattering,
             bool useBendingCorrection) {

  theUseMultipleScattering = useMultipleScattering;
  theUseBendingCorrection = useBendingCorrection;
  theLine = line;
  theMultScattCorrRPhi =0;
  theMScoeff=0;

  if (!theUseMultipleScattering && !theUseBendingCorrection) return;

  theBarrel = (layer->location() == GeomDetEnumerators::barrel);

  if (theUseMultipleScattering) {
    MultipleScatteringParametrisation sigmaRPhi(layer, es);
    theMultScattCorrRPhi = 3.f*sigmaRPhi(pt, line.cotLine(), constraint);
    float overSinTheta = std::sqrt(1.f+sqr(line.cotLine()));
    if (theBarrel) {
      theMScoeff =  theMultScattCorrRPhi*overSinTheta; 
    } else {
      float overCosTheta = std::abs(line.cotLine()) < 1.e-4f ? 
          1.e4f : overSinTheta/std::abs(line.cotLine());
      theMScoeff =  theMultScattCorrRPhi*overCosTheta;
      
    }
  }

  if (useBendingCorrection)  theBendingCorrection.init(pt,es);

}


void ThirdHitCorrection::correctRPhiRange( Range & range) const
{
  if (theUseMultipleScattering) {
    range.first -= theMultScattCorrRPhi;
    range.second += theMultScattCorrRPhi;
  }
}
void ThirdHitCorrection::correctRZRange( Range & range) const
{ 
  if (theUseMultipleScattering) {
    range.first -= theMScoeff;
    range.second += theMScoeff;
  } 

  if (theUseBendingCorrection) {
    if (theBarrel) {
      float cotTheta = theLine.cotLine();
      if (cotTheta > 0) {
        float radius = theLine.rAtZ(range.max());
        float corr = theBendingCorrection(radius) * cotTheta;
        range.second +=  corr;
      } else {
        float radius = theLine.rAtZ(range.min());
        float corr = theBendingCorrection(radius) * std::abs(cotTheta);
        range.first -=  corr;
      }
    } 
    else {
      float radius = range.max();
      float corr = theBendingCorrection(radius);
      range.first -= corr;
    }
  }
}