MultipleScatteringParametrisation Class Reference

#include <MultipleScatteringParametrisation.h>

Public Types
enum	Consecutive { notAssumeConsecutive, useConsecutive }
enum	X0Source { useDetLayer, useX0AtEta, useX0DataAveraged }

Public Member Functions
	MultipleScatteringParametrisation (const DetLayer *layer, const edm::EventSetup &iSetup, X0Source x0source=useX0AtEta)
float	operator() (float pt, float cotTheta, float transverseIP=0.) const
float	operator() (float pt, float cotTheta, const PixelRecoPointRZ &point, float transverseIP=0.) const
float	operator() (float pt, const PixelRecoPointRZ &point1, const PixelRecoPointRZ &point2, Consecutive consecutive=notAssumeConsecutive, float transverseIP=0.) const

Private Attributes
MSLayer	theLayer
MSLayersKeeper *	theLayerKeeper

Static Private Attributes
static const float	x0ToSigma = 0.0136f

Detailed Description

Parametrisation of multiple scattering sigma in tracker.

Definition at line 18 of file MultipleScatteringParametrisation.h.

Member Enumeration Documentation

enum MultipleScatteringParametrisation::Consecutive

Enumerator
notAssumeConsecutive
useConsecutive

Definition at line 23 of file MultipleScatteringParametrisation.h.

{ notAssumeConsecutive, useConsecutive };

enum MultipleScatteringParametrisation::X0Source

Enumerator
useDetLayer
useX0AtEta
useX0DataAveraged

Definition at line 22 of file MultipleScatteringParametrisation.h.

{ useDetLayer, useX0AtEta, useX0DataAveraged };

Constructor & Destructor Documentation

MultipleScatteringParametrisation::MultipleScatteringParametrisation	(	const DetLayer *	layer,
		const edm::EventSetup &	iSetup,
		X0Source	x0source = useX0AtEta
	)

Definition at line 28 of file MultipleScatteringParametrisation.cc.

References gather_cfg::cout.

{
  switch (x0Source) {
  case useX0AtEta: { 
    static MSLayersKeeperX0AtEta x0AtEta; 
    theLayerKeeper = &x0AtEta;
    break;
  }
  case useX0DataAveraged: {
    static MSLayersKeeperX0Averaged x0Averaged;
    theLayerKeeper = &x0Averaged;
    break;
  }

  case useDetLayer: {
    static MSLayersKeeperX0DetLayer x0DetLayer;
    theLayerKeeper = &x0DetLayer;
    break;
  }
  default:
    //FIXME should throw or similar
    cout << "** MultipleScatteringParametrisation ** wrong x0Source"<<endl;
    return;
  }
  theLayerKeeper->init(iSetup);
  if (!layer) return;
  theLayer = theLayerKeeper->layer(layer);
} 

Member Function Documentation

float MultipleScatteringParametrisation::operator()	(	float	pt,
		float	cotTheta,
		float	transverseIP = 0.
	)		const

MS sigma at the layer for which parametrisation is initialised; particle assumed to come from nominal vertex, "fast" methods called

Definition at line 59 of file MultipleScatteringParametrisation.cc.

{
  float sumX0D = theLayer.sumX0D(cotTheta); 
  return x0ToSigma * sumX0D /pT;
}

float MultipleScatteringParametrisation::operator()	(	float	pt,
		float	cotTheta,
		const PixelRecoPointRZ &	point,
		float	transverseIP = 0.
	)		const

MS sigma at the layer for which parametrisation is initialised; particle assumed to come from constraint point (inner to layer). layer by layer contribution is calculated

Definition at line 67 of file MultipleScatteringParametrisation.cc.

References MSLayersAtAngle::sumX0D().

{

  PixelRecoLineRZ lineIO(pointI, cotTheta, tip);
  PixelRecoPointRZ pointO = theLayer.crossing(lineIO).first;

  const MSLayersAtAngle & layersAtEta = theLayerKeeper->layers(cotTheta);
  
  float sumX0D = layersAtEta.sumX0D(pointI, pointO);
  return x0ToSigma * sumX0D /pT;
}

float MultipleScatteringParametrisation::operator()	(	float	pt,
		const PixelRecoPointRZ &	point1,
		const PixelRecoPointRZ &	point2,
		Consecutive	consecutive = notAssumeConsecutive,
		float	transverseIP = 0.
	)		const

MS sigma at the layer for which parametrisation is initialised; particle assumed to be measured at point1 and point2, it is assumed that layer is between point1 and point2. layer by layer contribution is calculated

Definition at line 81 of file MultipleScatteringParametrisation.cc.

References PixelRecoLineRZ::cotLine(), PixelRecoPointRZ::r(), mathSSE::sqrt(), and MSLayersAtAngle::sumX0D().

{   


  PixelRecoLineRZ lineIO(pointI, pointO, tip);
  PixelRecoPointRZ pointM = theLayer.crossing(lineIO).first;
  float cotTheta = lineIO.cotLine();

  if (consecutive==useConsecutive) {
    float dist = fabs(  (pointO.r()-pointM.r())
                      * (pointM.r()-pointI.r())
                      / (pointO.r()-pointI.r()) );
    return  x0ToSigma * sqrt(theLayer.x0(cotTheta)) * dist /pT;
  } else {
    const MSLayersAtAngle & layersAtEta = theLayerKeeper->layers(cotTheta);
    float sumX0D = layersAtEta.sumX0D(pointI, pointM, pointO);
    return x0ToSigma * sumX0D /pT;
  }
}

Member Data Documentation

MSLayer MultipleScatteringParametrisation::theLayer

private

Definition at line 54 of file MultipleScatteringParametrisation.h.

MSLayersKeeper* MultipleScatteringParametrisation::theLayerKeeper

private

Definition at line 55 of file MultipleScatteringParametrisation.h.

const float MultipleScatteringParametrisation::x0ToSigma = 0.0136f

staticprivate

Definition at line 56 of file MultipleScatteringParametrisation.h.