GsfMultipleScatteringUpdator Class Reference

#include <GsfMultipleScatteringUpdator.h>

Inheritance diagram for GsfMultipleScatteringUpdator:

Public Member Functions
GsfMultipleScatteringUpdator *	clone () const override
void	compute (const TrajectoryStateOnSurface &, const PropagationDirection, Effect[]) const override
	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::GsfMultipleScatteringUpdator ( float  mass )

inline

constructor with explicit mass

Definition at line 17 of file GsfMultipleScatteringUpdator.h.

: GsfMaterialEffectsUpdator(mass, 2) {}

Referenced by clone().

Member Function Documentation

clone()

GsfMultipleScatteringUpdator* GsfMultipleScatteringUpdator::clone ( void  ) const

inlineoverridevirtual

Implements GsfMaterialEffectsUpdator.

Definition at line 19 of file GsfMultipleScatteringUpdator.h.

{ return new GsfMultipleScatteringUpdator(*this); }

References GsfMultipleScatteringUpdator().

compute()

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

overridevirtual

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

Implements GsfMaterialEffectsUpdator.

Definition at line 9 of file GsfMultipleScatteringUpdator.cc.

                                                                   {
  //
  // 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);
    }
  }
}

References GetRecoTauVFromDQM_MC_cff::cl, materialEffect::Effect::deltaCov, h, MediumProperties::isValid(), TrajectoryStateOnSurface::localMomentum(), dqm-mbProfile::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(), trigObjTnPSource_cfi::var, w2, materialEffect::Effect::weight, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), z, and PV3DBase< T, PVType, FrameType >::z().

size()

virtual size_t GsfMultipleScatteringUpdator::size ( void  ) const

inlinevirtual

Definition at line 24 of file GsfMultipleScatteringUpdator.h.

{ return 2; }

Referenced by ntupleDataFormat._Collection::__iter__(), and ntupleDataFormat._Collection::__len__().