GsfMultipleScatteringUpdator Class Reference

#include <GsfMultipleScatteringUpdator.h>

Inheritance diagram for GsfMultipleScatteringUpdator:

Public Member Functions
virtual GsfMultipleScatteringUpdator *	clone () const
virtual void	compute (const TrajectoryStateOnSurface &, const PropagationDirection, Effect[]) const
	Computation: generates vectors of weights, means and standard deviations. More...
	GsfMultipleScatteringUpdator (float mass)
	constructor with explicit mass More...
virtual size_t	size () const
Public Member Functions inherited from GsfMaterialEffectsUpdator
	GsfMaterialEffectsUpdator (float mass, uint32_t is)
float	mass () const
size_t	size () const
virtual TrajectoryStateOnSurface	updateState (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const
virtual	~GsfMaterialEffectsUpdator ()

Additional Inherited Members
Public Types inherited from GsfMaterialEffectsUpdator
typedef materialEffect::Covariance	Covariance
typedef materialEffect::CovIndex	CovIndex
typedef materialEffect::Effect	Effect
Protected Member Functions inherited from GsfMaterialEffectsUpdator
void	resize (size_t is)

Detailed Description

Description of multiple scattering with two Gaussian components as described in HEPHY-PUB 724-99. Gaussians as a function of x/X0 are parametrized as polynomials. The mixture is parametrized as a function of the thickness, velocity and Xs=X0*h(Z).

Definition at line 14 of file GsfMultipleScatteringUpdator.h.

Constructor & Destructor Documentation

GsfMultipleScatteringUpdator::GsfMultipleScatteringUpdator ( float  mass )

inline

constructor with explicit mass

Definition at line 19 of file GsfMultipleScatteringUpdator.h.

Referenced by clone().

                                           :
    GsfMaterialEffectsUpdator(mass,2) {}

Member Function Documentation

virtual GsfMultipleScatteringUpdator* GsfMultipleScatteringUpdator::clone ( void  ) const

inlinevirtual

Implements GsfMaterialEffectsUpdator.

Definition at line 22 of file GsfMultipleScatteringUpdator.h.

References GsfMultipleScatteringUpdator().

  {
    return new GsfMultipleScatteringUpdator(*this);
  }

void GsfMultipleScatteringUpdator::compute ( const TrajectoryStateOnSurface &  TSoS, const PropagationDirection  propDir, Effect  effects[]  ) const

virtual

Computation: generates vectors of weights, means and standard deviations.

Implements GsfMaterialEffectsUpdator.

Definition at line 10 of file GsfMultipleScatteringUpdator.cc.

References GetRecoTauVFromDQM_MC_cff::cl, constexpr, materialEffect::Effect::deltaCov, h, MediumProperties::isValid(), TrajectoryStateOnSurface::localMomentum(), fff_deleter::log, PV3DBase< T, PVType, FrameType >::mag(), GsfMaterialEffectsUpdator::mass(), Surface::mediumProperties(), materialEffect::msxx, materialEffect::msxy, materialEffect::msyy, AlCaHLTBitMon_ParallelJobs::p, PV3DBase< T, PVType, FrameType >::perp(), funct::pow(), MediumProperties::radLen(), mathSSE::sqrt(), TrajectoryStateOnSurface::surface(), MetTreeProducer::var(), w2, materialEffect::Effect::weight, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), detailsBasic3DVector::z, and PV3DBase< T, PVType, FrameType >::z().

{
  //
  // Get surface and check presence of medium properties
  //
  const Surface& surface = TSoS.surface();
  //
  // calculate components
  //
  if ( surface.mediumProperties().isValid() ) {
    LocalVector pvec = TSoS.localMomentum();
    float p = TSoS.localMomentum().mag();
    pvec *= 1./p;
    // thickness in radiation lengths
    float rl = surface.mediumProperties().radLen()/fabs(pvec.z());
    // auxiliary variables for modified X0
    constexpr float z = 14;                 // atomic number of silicon
    const float logz = log(z);
    const float h = (z+1)/z*log(287*sqrt(z))/log(159*pow(z,-1./3.));
    float beta2 = 1./(1.+mass()*mass()/p/p);
    // reduced thickness
    float dp1 = rl/beta2/h;
    float logdp1 = log(dp1);
    float logdp2 = 2./3.*logz + logdp1;
    // weights
    float w2;
    if ( logdp2<log(0.5) )  
      w2 = 0.05283+0.0077*logdp2+0.00069*logdp2*logdp2;
    else
      w2 =-0.01517+0.1151*logdp2-0.00653*logdp2*logdp2;
    float w1 = 1.-w2;
    effects[0].weight*=w1;
    effects[1].weight*=w2;
    // reduced variances
    float var1 = 0.8510+0.03314*logdp1-0.001825*logdp1*logdp1;
    float var2 = (1.-w1*var1)/w2;
    for ( int ic=0; ic<2; ic++ ) {
      // choose component and multiply with total variance
      float var = ic==0 ? var1 : var2;
      var *= 225.e-6*dp1/p/p;
      AlgebraicSymMatrix55 cov;
      // transform from orthogonal planes containing the
      // momentum vector to local parameters
      float sl = pvec.perp();
      float cl = pvec.z();
      float cf = pvec.x()/sl;
      float sf = pvec.y()/sl;
      using namespace materialEffect;
      effects[ic].deltaCov[msxx] += var*(sf*sf*cl*cl + cf*cf)/(cl*cl*cl*cl);
      effects[ic].deltaCov[msxy] += var*(cf*sf*sl*sl        )/(cl*cl*cl*cl);
      effects[ic].deltaCov[msyy] += var*(cf*cf*cl*cl + sf*sf)/(cl*cl*cl*cl);
    }
  }

}

virtual size_t GsfMultipleScatteringUpdator::size ( void  ) const

inlinevirtual

Definition at line 30 of file GsfMultipleScatteringUpdator.h.

{ return 2;}