BeamParameters Class Reference

This class contains the nominal beam parameters and the parameters used for smearing of the primary vertex and the beam energy and momentum. More...

#include <BeamParameters.h>

Inheritance diagram for BeamParameters:

Collaboration diagram for BeamParameters:

Public Types
enum	EGenerationFlags {   c_generateCMS = 1 << 0 ,   c_smearBeamEnergy = 1 << 1 ,   c_smearBeamDirection = 1 << 2 ,   c_smearBeam = c_smearBeamEnergy | c_smearBeamDirection ,   c_smearVertex = 1 << 3 ,   c_smearALL = c_smearVertex | c_smearBeam }
	Possible Flags for initial event generation. More...

Public Member Functions
	BeamParameters ()
	Default constructor.
	BeamParameters (const BeamParameters &b)
	Copy constructor.
BeamParameters &	operator= (const BeamParameters &b)
	Assignment operator.
bool	operator== (const BeamParameters &b) const
	Equality operator.
void	setGenerationFlags (int flags) override
	Set the generation flags to be used for event generation (ORed combination of EGenerationFlags). More...
void	setCovHER (const TMatrixDSym &cov)
	Set the covariance matrix for HER (E, theta_x, theta_y) where E is the energy, theta_x is the horizontal angle between nominal direction and actual direction in spread and theta_y is the vertical angle The upper triangle will be saved.
void	setCovLER (const TMatrixDSym &cov)
	Set the covariance matrix for LER (E, theta_x, theta_y) where E is the energy, theta_x is the horizontal angle between nominal direction and actual direction in spread and theta_y is the vertical angle. More...
void	setCovVertex (const TMatrixDSym &cov)
	Set the covariance matrix of the vertex position. More...
void	setHER (double energy, double angleX, double angleY, const std::vector< double > &cov)
	Set the HER FourVector and error matrix from beam energy, angle and covariance entries. More...
void	setLER (double energy, double angleX, double angleY, const std::vector< double > &cov)
	Set the LER FourVector and error matrix from beam energy, angle and covariance entries. More...
void	setVertex (const TVector3 &vertex, const std::vector< double > &cov)
	Set the vertex position and error matrix. More...
TMatrixDSym	getCovHER () const
	Get the covariance matrix of HER (E, theta_x, theta_y) where E is the energy, theta_x is the horizontal angle between nominal direction and actual direction in spread and theta_y is the vertical angle.
TMatrixDSym	getCovLER () const
	Get the covariance matrix of LER (E, theta_x, theta_y) where E is the energy, theta_x is the horizontal angle between nominal direction and actual direction in spread and theta_y is the vertical angle.
TMatrixDSym	getCovVertex () const
	Get the covariance matrix of the vertex position.
void	setLER (const ROOT::Math::PxPyPzEVector &ler)
	Set the Low Energy Beam 4-momentum.
void	setHER (const ROOT::Math::PxPyPzEVector &her)
	Set the High Energy Beam 4-momentum.
void	setVertex (const B2Vector3D &vertex)
	Set the vertex position.
bool	operator== (const MCInitialParticles &b) const
	Equality operator.
void	set (const ROOT::Math::PxPyPzEVector &her, const ROOT::Math::PxPyPzEVector &ler, const B2Vector3D &vertex)
	Set the initial event values, i.e. More...
void	setHER (const ROOT::Math::PxPyPzEVector &her)
	Set the High Energy Beam 4-momentum.
void	setLER (const ROOT::Math::PxPyPzEVector &ler)
	Set the Low Energy Beam 4-momentum.
void	setVertex (const B2Vector3D &vertex)
	Set the vertex position.
void	setTime (double time)
	Set collison time.
const ROOT::Math::PxPyPzEVector &	getHER () const
	Get 4vector of the high energy beam.
const ROOT::Math::PxPyPzEVector &	getLER () const
	Get 4vector of the low energy beam.
const B2Vector3D &	getVertex () const
	Get the position of the collision.
double	getTime () const
	Get collison time.
double	getEnergy () const
	Get the the actual collision energy (in lab system)
double	getMass () const
	Get the invariant mass of the collision (= energy in CMS)
const ROOT::Math::LorentzRotation &	getLabToCMS () const
	Return the LorentzRotation to convert from lab to CMS frame.
const ROOT::Math::LorentzRotation &	getCMSToLab () const
	Return the LorentzRotation to convert from CMS to lab frame.
bool	getValidFlag () const
	Get the flag to check if a valid MCInitialParticles object was already generated and filled in an event.
int	getGenerationFlags () const
	Get the generation flags to be used for event generation (ORed combination of EGenerationFlags)
bool	hasGenerationFlags (int flags) const
	Check if a certain set of EGenerationFlags is set.
std::string	getGenerationFlagString (const std::string &separator=" ") const
	Return string representation of all active flags for printing. More...

Protected Attributes
int	m_generationFlags {0}
	Flags to be used when generating events.

Private Member Functions
	ClassDefOverride (BeamParameters, 3)
	ClassDef.
void	calculateBoost () const
	Calculate the boost if necessary.
void	resetBoost ()
	Reset cached transformations after changing parameters.
	ClassDef (MCInitialParticles, 4)
	ROOT Dictionary.

Static Private Member Functions
static ROOT::Math::PxPyPzEVector	getFourVector (double energy, double angleX, double angleY)
	Calculate FourVector of a beam from energy and angle wrt the z-axis. More...
static void	setCovMatrix (Double32_t *member, const std::vector< double > &cov, bool common)
	Set covariance matrix from vector of entries. More...
static void	setCovMatrix (Double32_t *member, const TMatrixDSym &cov)
	Set covariance matrix from ROOT Matrix object.
static TMatrixDSym	getCovMatrix (const Double32_t *member)
	Obtain covariance matrix from a given float array.

Private Attributes
Double32_t	m_covHER [6]
	Covariance matrix of the high energy beam at the IP.
Double32_t	m_covLER [6]
	Covariance matrix of the low energy beam at the IP.
Double32_t	m_covVertex [6]
	Covariance matrix of the vertex position.
ROOT::Math::PxPyPzEVector	m_her
	HER 4vector.
ROOT::Math::PxPyPzEVector	m_ler
	LER 4vector.
B2Vector3D	m_vertex
	collision position
double	m_time = 0
	collision time
ROOT::Math::LorentzRotation *	m_labToCMS {nullptr}
	Boost from Lab into CMS. More...
ROOT::Math::LorentzRotation *	m_CMSToLab {nullptr}
	transient More...
double	m_invariantMass {0.0}
	transient More...
bool	m_validFlag = false
	transient More...

Detailed Description

This class contains the nominal beam parameters and the parameters used for smearing of the primary vertex and the beam energy and momentum.

It is event independent (but might be run or even sub run dependent)

Definition at line 25 of file BeamParameters.h.

Member Enumeration Documentation

EGenerationFlags

enum EGenerationFlags

inherited

Possible Flags for initial event generation.

Enumerator
c_generateCMS	generate initial event in CMS instead of lab
c_smearBeamEnergy	smear energy of HER and LER (but not direction)
c_smearBeamDirection	smear direction of HER and LER (but not energy)
c_smearBeam	smear the full beam momentum (energy and direction)
c_smearVertex	smear vertex
c_smearALL	smear all

Definition at line 36 of file MCInitialParticles.h.

Member Function Documentation

getFourVector()

ROOT::Math::PxPyPzEVector getFourVector ( double  energy, double  angleX, double  angleY  )

staticprivate

Calculate FourVector of a beam from energy and angle wrt the z-axis.

Negative angles will be treated as angle = M_PI - fabs(angle)

Parameters

energy	beam energy
angleX	horizontal angle wrt z-axis
angleY	vertical angle wrt z-axis

Definition at line 49 of file BeamParameters.cc.

{
  double p = sqrt(pow(energy, 2) - pow(Const::electronMass, 2));
  if (angleX < 0) {
    angleX = M_PI + angleX;
    angleY = M_PI + angleY;
  }
 
  double Sign = cos(angleX) < 0 ?  -1 : 1;
 
  double pzTerm = 1 - pow(sin(angleX), 2) - pow(sin(angleY), 2);
  B2ASSERT("Angular term should be positive", pzTerm >= 0);
 
  double pz = Sign * p * sqrt(pzTerm);
 
  return ROOT::Math::PxPyPzEVector(p * sin(angleX), p * sin(angleY), pz, energy);
 
}

getGenerationFlagString()

std::string getGenerationFlagString ( const std::string &  separator = " " ) const

inherited

Return string representation of all active flags for printing.

Parameters

separator

separation string to be put between flags

Definition at line 13 of file MCInitialParticles.cc.

set()

void set ( const ROOT::Math::PxPyPzEVector &  her, const ROOT::Math::PxPyPzEVector &  ler, const B2Vector3D &  vertex  )

inlineinherited

Set the initial event values, i.e.

the four momenta of both beams and the vertex

Parameters

her	4vector of the high energy beam
ler	4vector of the low energy beam
vertex	position of the actual collision vertex

Definition at line 97 of file MCInitialParticles.h.

setCovLER()

void setCovLER ( const TMatrixDSym &  cov )

inline

Set the covariance matrix for LER (E, theta_x, theta_y) where E is the energy, theta_x is the horizontal angle between nominal direction and actual direction in spread and theta_y is the vertical angle.

The upper triangle will be saved.

Definition at line 97 of file BeamParameters.h.

{ setCovMatrix(m_covLER, cov); }

setCovMatrix()

void setCovMatrix ( Double32_t *  member, const std::vector< double > &  cov, bool  common  )

staticprivate

Set covariance matrix from vector of entries.

The vector for the covariance matrix can have either 0, 1, 3, 6 or 9 entries:

• 0 entries means no error.
• 1 entry will be treated as the common variance for all variables if common is true. Otherwise it will be taken as the variance of just the first element.
• 3 entries will be treated as uncorrelated variances for all variables (diagonal of the matrix)
• 6 entries will be interpreted as the upper triangle of the covariance matrix with the element order being (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2)
• 9 entries for the full covariance matrix in row-major order. The symmetry of the matrix will not be checked but just the lower triangle will be used.

Parameters

member	to the member which contains the matrix
cov	entries for the covariance matrix
common	if true a 1-element cov will be treated as the common variance for all diagonal elements

Definition at line 88 of file BeamParameters.cc.

setCovVertex()

void setCovVertex ( const TMatrixDSym &  cov )

inline

Set the covariance matrix of the vertex position.

The upper triangle will be saved.

Definition at line 100 of file BeamParameters.h.

setGenerationFlags()

void setGenerationFlags ( int  flags )

inlineoverridevirtual

Set the generation flags to be used for event generation (ORed combination of EGenerationFlags).

The only difference w.r.t. MCInitialParticles::setGenerationFlags() is that a WARNING is thrown if a flag different from 14 (= all the smearings turned on) is set.

Reimplemented from MCInitialParticles.

Definition at line 74 of file BeamParameters.h.

setHER()

void setHER	(	double	energy,
		double	angleX,
		double	angleY,
		const std::vector< double > &	cov
	)

Set the HER FourVector and error matrix from beam energy, angle and covariance entries.

The vector for the covariance matrix can have either 0, 1, 3, 6 or 9 entries:

• 0 entries means no error.
• 1 entry will be treated as the variance of the beam energy.
• 3 entries will be treated as uncorrelated variances for all variables (diagonal of the matrix)
• 6 entries will be interpreted as the upper triangle of the covariance matrix with the element order being (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2)
• 9 entries for the full covariance matrix in row-major order. The symmetry of the matrix will not be checked but just the lower triangle will be used.

Parameters

energy	beam energy
angleX	angle between beam direction and z axis (in the x-z plane). Negative values are treated as M_PI - abs(angle)
angleY	angle between beam direction and z axis (in the y-z plane). Negative values are treated as M_PI - abs(angle)
cov	entries of the covariance matrix.

Definition at line 36 of file BeamParameters.cc.

setLER()

void setLER	(	double	energy,
		double	angleX,
		double	angleY,
		const std::vector< double > &	cov
	)

Set the LER FourVector and error matrix from beam energy, angle and covariance entries.

The vector for the covariance matrix can have either 0, 1, 3, 6 or 9 entries:

• 0 entries means no error.
• 1 entry will be treated as the variance of the beam energy.
• 3 entries will be treated as uncorrelated variances for all variables (diagonal of the matrix)
• 6 entries will be interpreted as the upper triangle of the covariance matrix with the element order being (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2)
• 9 entries for the full covariance matrix in row-major order. The symmetry of the matrix will not be checked but just the lower triangle will be used.

Parameters

energy	beam energy
angleX	angle between beam direction and z axis (in the x-z plane). Negative values are treated as M_PI - abs(angle)
angleY	angle between beam direction and z axis (in the y-z plane). Negative values are treated as M_PI - abs(angle)
cov	entries of the covariance matrix.

Definition at line 29 of file BeamParameters.cc.

setVertex()

void setVertex	(	const TVector3 &	vertex,
		const std::vector< double > &	cov
	)

Set the vertex position and error matrix.

The vector for the covariance matrix can have either 0, 1, 3, 6 or 9 entries:

• 0 entries means no error.
• 1 entry will be treated as the common variance for x, y and z
• 3 entries will be treated as uncorrelated variances for all variables (diagonal of the matrix)
• 6 entries will be interpreted as the upper triangle of the covariance matrix with the element order being (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2)
• 9 entries for the full covariance matrix in row-major order. The symmetry of the matrix will not be checked but just the upper triangle will be used.

Parameters

vertex	vertex position
cov	entries of the covariance matrix.

Definition at line 43 of file BeamParameters.cc.

Member Data Documentation

m_CMSToLab

ROOT::Math::LorentzRotation* m_CMSToLab {nullptr}

mutableprivateinherited

transient

Boost from CMS into lab. (calculated on first use, not saved to file)

Definition at line 192 of file MCInitialParticles.h.

m_invariantMass

double m_invariantMass {0.0}

mutableprivateinherited

transient

invariant mass of HER+LER (calculated on first use, not saved to file)

Definition at line 194 of file MCInitialParticles.h.

m_labToCMS

ROOT::Math::LorentzRotation* m_labToCMS {nullptr}

mutableprivateinherited

Boost from Lab into CMS.

(calculated on first use, not saved to file)

Definition at line 190 of file MCInitialParticles.h.

m_validFlag

bool m_validFlag = false

privateinherited

transient

Flag to check if a valid MCInitialParticles object was already generated and filled in an event.

Definition at line 196 of file MCInitialParticles.h.

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

• framework/dbobjects/include/BeamParameters.h
• framework/dbobjects/src/BeamParameters.cc