This class contains the measured values of the orientation of the collision axis in the CM system obtained by pure Lorentz boost angleXZ = atan(pHERcms.X / pHERcms.Z) angleYZ = atan(pHERcms.Y / pHERcms.Z) where pHERcms is HER momentum in CM system obtained by boost. More...

#include <CollisionAxisCMS.h>

Inheritance diagram for CollisionAxisCMS:

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Collaboration diagram for CollisionAxisCMS:

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Public Member Functions
bool	operator== (const CollisionAxisCMS &other) const
	equality operator

void	setAngles (double angleXZ, double angleYZ, const TMatrixDSym &centerCovariance)
	Set the central values and uncertainty of them.

void	setSpread (const TMatrixDSym &spreadCovariance, double spreadXZunc, double spreadYZunc, double spreadPhiUnc)
	Set spread covariance and uncertainties of the eigenvalues of this matrix.

double	getAngleXZ () const
	Get the mean XZ angle of the HER beam in the CM frame obtained by pure boost.

double	getAngleYZ () const
	Get the mean YZ angle of the HER beam in the CM frame obtained by pure boost.

const TMatrixDSym &	getCenterCovariance () const
	Get the covariance matrix describing uncertainties of m_angleXZ and m_angleYZ.

const TMatrixDSym &	getSpreadCovariance () const
	Get the covariance matrix describing "natural" spread of angleXZ and angleYZ.

double	getSpreadXZunc () const
	Get the uncertainty of the eigenvalue of m_spreadCovariance corresponding to eigenvector closer to x-axis

double	getSpreadYZunc () const
	Get the uncertainty of the eigenvalue of m_spreadCovariance corresponding to eigenvector closer to y-axis

double	getSpreadPhiUnc () const
	Get the uncertainty of the angle of the eigenvector of m_spreadCovariance.

Private Member Functions
	ClassDef (CollisionAxisCMS, 1)
	direction of collision axis in CMS and its spread

Private Attributes
double	m_angleXZ
	the XZ angle of the HER beam in the CM system obtained by pure boost

double	m_angleYZ
	the YZ angle of the HER beam in the CM system obtained by pure boost

TMatrixDSym	m_centerCovariance {2}
	Covariance matrix describing uncertainties of m_angleXZ and m_angleYZ.

TMatrixDSym	m_spreadCovariance {2}
	Covariance matrix describing "natural" spread of m_angleXZ and m_angleYZ.

double	m_spreadXZunc
	Uncertainty of the eigenvalue of m_spreadCovariance corresponding to eigenvector closer to x-axis.

double	m_spreadYZunc
	Uncertainty of the eigenvalue of m_spreadCovariance corresponding to eigenvector closer to y-axis.

double	m_spreadPhiUnc
	Uncertainty of the angle of the eigenvector of m_spreadCovariance.

Detailed Description

This class contains the measured values of the orientation of the collision axis in the CM system obtained by pure Lorentz boost angleXZ = atan(pHERcms.X / pHERcms.Z) angleYZ = atan(pHERcms.Y / pHERcms.Z) where pHERcms is HER momentum in CM system obtained by boost.

These angles do not have sharp value, but vary event-by-event due to the spread of HER/LER momenta. Therefore, both central values and spread are stored together with the uncertainties.

This class is needed for Lorentz transformation to the standard CM system, where particles collide along z-axis.

Definition at line 27 of file CollisionAxisCMS.h.

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

mdst/dbobjects/include/CollisionAxisCMS.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description