This class contains the initial state for the given event. More...

#include <MCInitialParticles.h>

Inheritance diagram for MCInitialParticles:

Collaboration diagram for MCInitialParticles:

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
	MCInitialParticles ()
	Default constructor.

	MCInitialParticles (const MCInitialParticles &b)
	Copy constructor.

MCInitialParticles &	operator= (const MCInitialParticles &b)
	Assignment operator.

bool	operator== (const MCInitialParticles &b) const
	Equality operator.

virtual	~MCInitialParticles ()
	Free memory of the LorentzRotation if it was created.

void	set (const ROOT::Math::PxPyPzEVector &her, const ROOT::Math::PxPyPzEVector &ler, const ROOT::Math::XYZVector &vertex)
	Set the initial event values, i.e. More...

void	setByLorentzTransformation (double Ecms, double bX, double bY, double bZ, double angleXZ, double angleYZ, const ROOT::Math::XYZVector &vertex)
	Initialize the event values from CMS energy and parameters of the Lorentz transformation between LAB and CMS. 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 ROOT::Math::XYZVector &vertex)
	Set the vertex position.

void	setTime (double time)
	Set collison time.

virtual void	setGenerationFlags (int flags)
	Set the generation flags to be used for event generation (ORed combination of EGenerationFlags)

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 ROOT::Math::XYZVector &	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...

Static Public Member Functions
static ROOT::Math::LorentzRotation	cmsToLab (double bX, double bY, double bZ, double angleXZ, double angleYZ)
	Return the LorentzRotation from CMS to LAB based on the following parameters. More...

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

Private Member Functions
void	calculateBoost () const
	Calculate the boost if necessary.

void	resetBoost ()
	Reset cached transformations after changing parameters.

	ClassDef (MCInitialParticles, 5)
	ROOT Dictionary.

Private Attributes
ROOT::Math::PxPyPzEVector	m_her
	HER 4vector.

ROOT::Math::PxPyPzEVector	m_ler
	LER 4vector.

ROOT::Math::XYZVector	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 initial state for the given event.

This is not to be confused with the nominal beam parameters but is an event dependent info which contains all implemented smearing effects. It is only set in Montecarlo.

Definition at line 31 of file MCInitialParticles.h.

Member Enumeration Documentation

◆ EGenerationFlags

enum EGenerationFlags

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.

                           {
       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,
     };

Member Function Documentation

◆ cmsToLab()

ROOT::Math::LorentzRotation cmsToLab	(	double	bX,
		double	bY,
		double	bZ,
		double	angleXZ,
		double	angleYZ
	)

static

Return the LorentzRotation from CMS to LAB based on the following parameters.

Parameters

bX	x-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
bY	y-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
bZ	z-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
angleXZ	angle in the XZ plane of the collision axis in the CM system obtained by pure boost
angleYZ	angle in the YZ plane of the collision axis in the CM system obtained by pure boost

Definition at line 31 of file MCInitialParticles.cc.

 {
   //boost to CM frame
   ROOT::Math::LorentzRotation boost(ROOT::Math::Boost(-1.*ROOT::Math::XYZVector(bX, bY, bZ)));
  
  
   //rotation such that the collision axis is aligned with z-axis
   ROOT::Math::XYZVector zaxis(0., 0., 1.); //target collision axis
  
   double tanAngleXZ = tan(angleXZ);
   double tanAngleYZ = tan(angleYZ);
   double Norm   = 1 / sqrt(1 + pow(tanAngleXZ, 2) + pow(tanAngleYZ, 2));
   ROOT::Math::XYZVector electronCMS(Norm * tanAngleXZ, Norm * tanAngleYZ, Norm); //current collision axis
  
   ROOT::Math::XYZVector rotAxis = zaxis.Cross(electronCMS);
   double rotangle = asin(rotAxis.R());
  
   ROOT::Math::LorentzRotation rotation(ROOT::Math::AxisAngle(rotAxis, -rotangle));
  
  
   ROOT::Math::LorentzRotation trans  = rotation * boost;
   ROOT::Math::LorentzRotation transI = trans.Inverse();
   return transI;
 }

◆ getGenerationFlagString()

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

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 ROOT::Math::XYZVector &	vertex
	)

inline

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.

◆ setByLorentzTransformation()

void setByLorentzTransformation	(	double	Ecms,
		double	bX,
		double	bY,
		double	bZ,
		double	angleXZ,
		double	angleYZ,
		const ROOT::Math::XYZVector &	vertex
	)

inline

Initialize the event values from CMS energy and parameters of the Lorentz transformation between LAB and CMS.

In addition the vertex is also initialized.

Parameters

Ecms	centre-of-mass energy of the collision
bX	x-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
bY	y-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
bZ	z-component of the boost vector, i.e. of (pHER + pLER) / (eHER + eLER), where pHER & pLER are momentum 3-vectors
angleXZ	angle in the XZ plane of the collision axis in the CM system obtained by pure boost
angleYZ	angle in the YZ plane of the collision axis in the CM system obtained by pure boost
vertex	position of the actual collision vertex

Definition at line 116 of file MCInitialParticles.h.

Member Data Documentation

◆ m_CMSToLab

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

mutableprivate

transient

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

Definition at line 233 of file MCInitialParticles.h.

◆ m_invariantMass

double m_invariantMass {0.0}

mutableprivate

transient

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

Definition at line 235 of file MCInitialParticles.h.

◆ m_labToCMS

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

mutableprivate

Boost from Lab into CMS.

(calculated on first use, not saved to file)

Definition at line 231 of file MCInitialParticles.h.

◆ m_validFlag

bool m_validFlag = false

private

transient

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

Definition at line 237 of file MCInitialParticles.h.

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

framework/dataobjects/include/MCInitialParticles.h
framework/dataobjects/src/MCInitialParticles.cc

Public Types

Public Member Functions

Static Public Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ EGenerationFlags

Member Function Documentation

◆ cmsToLab()

◆ getGenerationFlagString()

◆ set()

◆ setByLorentzTransformation()

Member Data Documentation

◆ m_CMSToLab

◆ m_invariantMass

◆ m_labToCMS

◆ m_validFlag