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, int il,
                  bool useMultipleScattering,
                  bool useBendingCorrection) {
  
  theUseMultipleScattering = useMultipleScattering;
  theUseBendingCorrection = useBendingCorrection;
  theLine = line;
  theMultScattCorrRPhi =0;
  theMScoeff=0;

  theBarrel = layer->isBarrel();

  if (theUseMultipleScattering) {
    MultipleScatteringParametrisation sigmaRPhi(layer, es);
    theMultScattCorrRPhi = 3.f*sigmaRPhi(pt, line.cotLine(), constraint, il);
    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::correctRZRange( Range & range) const
{ 
  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;
    }
  }
}