xAOD::NeutralParticle_v1 Class Reference

#include <NeutralParticle_v1.h>

Inheritance diagram for xAOD::NeutralParticle_v1:
xAOD::IParticle SG::AuxElement SG::IAuxElement

List of all members.

Public Member Functions

 NeutralParticle_v1 ()
 Default constructor.
 ~NeutralParticle_v1 ()
 Destructor.
 NeutralParticle_v1 (const NeutralParticle_v1 &o)
 Copy ctor. This involves copying the entire Auxilary store, and is a slow operation which should be used sparingly.
NeutralParticle_v1 & operator= (const NeutralParticle_v1 &tp)
 Assignment operator. This can involve creating and copying an Auxilary store, and so should be used sparingly.

xAOD::IParticle functions

The transverse momentum ($p_T$) of the particle.



typedef IParticle::FourMom_t FourMom_t
 Definition of the 4-momentum type.
virtual double pt () const
 The transverse momentum ($p_T$) of the particle.
virtual double eta () const
 The pseudorapidity ($\eta$) of the particle.
virtual double phi () const
 The azimuthal angle ($\phi$) of the particle.
virtual double m () const
 The invariant mass of the particle..
virtual double e () const
 The total energy of the particle.
virtual double rapidity () const
 The true rapidity (y) of the particle.
virtual const FourMom_t & p4 () const
 The full 4-momentum of the particle.
virtual Type::ObjectType type () const
 The type of the object as a simple enumeration.

Defining parameters functions

The 'defining parameters' are key to the concept of a NeutralParticle, and give the values for the IParticle interface ( pt(), phi(), eta() etc.). They use the Trk::NeutralPerigee coordinate system, and are defined as: $( d_0, z_0, \phi, \theta, q/p )$. The parameters are expressed with respect to an origin (returned by vx(), vy() and vy() ), currently intended to be the 'beamspot'. This origin is expected to be the same for all track particles in a collection (and this may be be enforced).



float d0 () const
 Returns the $d_0$ parameter.
float z0 () const
 Returns the $z_0$ parameter.
float phi0 () const
 Returns the $\phi$ parameter, which has range $-\pi$ to $+\pi$.
float theta () const
 Returns the $\theta$ parameter, which has range 0 to $\pi$.
float oneOverP () const
 Returns the $q/p$ parameter.
const DefiningParameters_t & definingParameters () const
 Returns a SVector of the Perigee track parameters. i.e. a vector of $\left(\begin{array}{c}d_0\\z_0\\\phi_0\\\theta\\q/p\end{array}\right)$.
const ParametersCovMatrix_t & definingParametersCovMatrix () const
 Returns the 5x5 symmetric matrix containing the defining parameters covariance matrix.
const std::vector< float > & definingParametersCovMatrixVec () const
 Returns the vector of the covariance values - 15 elements.
void setDefiningParameters (float d0, float z0, float phi0, float theta, float qOverP)
 Set the defining parameters.
void setDefiningParametersCovMatrix (const ParametersCovMatrix_t &cov)
 Set the defining parameters covariance matrix.
void setDefiningParametersCovMatrixVec (const std::vector< float > &cov)
 Set the defining parameters covariance matrix using a length 15 vector.
float vx () const
 The x origin for the parameters.
float vy () const
 The y origin for the parameters.
float vz () const
 The z origin for the parameters.
void setParametersOrigin (float x, float y, float z)
 Set the origin for the parameters.
const Trk::NeutralPerigee & perigeeParameters () const
 Returns the Trk::NeutralPerigee track parameters.

Detailed Description

Class describing a NeutralParticle.

Author:
Andreas Salzburger <Andreas.Salzburger@cern.ch>

Member Function Documentation

const NeutralParticle_v1::FourMom_t & xAOD::NeutralParticle_v1::p4 (  )  const [virtual]

The full 4-momentum of the particle.

Todo:
Get value from somewhere. Also, the TrackParticle took the Pion mass - do we really want to do this? We have ParticleHypo?

Implements xAOD::IParticle.

const Trk::NeutralPerigee & xAOD::NeutralParticle_v1::perigeeParameters (  )  const

Returns the Trk::NeutralPerigee track parameters.

These are defined as: $\left(\begin{array}{c}d_0\\z_0\\\phi_0\\\theta\\1/p\\\end{array}\right)$

Note:
This is only available in Athena.
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