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LayerCrossingSide Class Reference

Helper class to determine if a TrajectoryStateOnSurface would cross a layer from the inside, or from the outside, if propagated with a propagator with a defined direction. More...

#include <RecoTracker/TkDetLayers/interface/LayerCrossingSide.h>

List of all members.

Public Member Functions
int	barrelSide (const TrajectoryStateOnSurface &startingState, const Propagator &prop) const
	returns 0 if barrel layer crossed from inside, 1 if from outside
int	endcapSide (const TrajectoryStateOnSurface &startingState, const Propagator &prop) const
	returns 0 if endcap layer crossed from inside, ie from the side of the interation region, 1 if from outside

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Detailed Description

Helper class to determine if a TrajectoryStateOnSurface would cross a layer from the inside, or from the outside, if propagated with a propagator with a defined direction.

No propagations performed, the result is very fast but not correct in case of a looping track that first goes outwards, then inwards, before crossing a layer.

Definition at line 14 of file LayerCrossingSide.h.

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Member Function Documentation

int LayerCrossingSide::barrelSide	(	const TrajectoryStateOnSurface &	startingState,
		const Propagator &	prop
	)			const [inline]

returns 0 if barrel layer crossed from inside, 1 if from outside

Definition at line 18 of file LayerCrossingSide.h.

References alongMomentum, Vector3DBase< T, FrameTag >::dot(), TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), oppositeToMomentum, Propagator::propagationDirection(), PV3DBase< T, PVType, FrameType >::x(), and PV3DBase< T, PVType, FrameType >::y().

                                                                                              {
    GlobalPoint pos = startingState.globalPosition();
    GlobalVector radial(pos.x(), pos.y(), 0);
    if (startingState.globalMomentum().dot( radial) > 0) {  // momentum points outwards
      return (prop.propagationDirection() == alongMomentum ? 0 : 1);
    }
    else {  // momentum points inwards
      return (prop.propagationDirection() == oppositeToMomentum ? 0 : 1);
    }
  }

int LayerCrossingSide::endcapSide	(	const TrajectoryStateOnSurface &	startingState,
		const Propagator &	prop
	)			const [inline]

returns 0 if endcap layer crossed from inside, ie from the side of the interation region, 1 if from outside

Definition at line 32 of file LayerCrossingSide.h.

References alongMomentum, TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), oppositeToMomentum, Propagator::propagationDirection(), and PV3DBase< T, PVType, FrameType >::z().

                                                                                              {
    float zpos = startingState.globalPosition().z();
    if (startingState.globalMomentum().z() * zpos > 0) {  // momentum points outwards
      return (prop.propagationDirection() == alongMomentum ? 0 : 1);
    }
    else {  // momentum points inwards
      return (prop.propagationDirection() == oppositeToMomentum ? 0 : 1);
    }
  }

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The documentation for this class was generated from the following file:

• RecoTracker/TkDetLayers/interface/LayerCrossingSide.h

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