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.

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.

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 collision 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 collision time.

double	getEnergy () const
	Get the actual collision energy (in lab system)

double	getMass () const
	Get the invariant mass of the collision (= energy in CMS)

ROOT::Math::XYZVector	getBoostVector () const
	Get the boost vector (velocity of system produced in the collision)

ROOT::Math::PxPyPzEVector	getBoostedHER () const
	Get the 4-vector of electron beam in CM system obtained by pure boost.

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.

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.

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

Private Member Functions
void	calculateBoost () const
	Calculate the Lorentz transformations LAB->CMS & CMS->LAB 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.

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

double	m_invariantMass {0.0}
	transient

ROOT::Math::PxPyPzEVector	m_boostedHER
	transient

bool	m_validFlag = false
	transient

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,
    };

Constructor & Destructor Documentation

◆ MCInitialParticles() [1/2]

MCInitialParticles ( )

inline

Default constructor.

Definition at line 52 of file MCInitialParticles.h.

52: TObject() {}

◆ MCInitialParticles() [2/2]

MCInitialParticles ( const MCInitialParticles & b )

inline

Copy constructor.

Definition at line 55 of file MCInitialParticles.h.

55 : TObject(), m_her(b.m_her), m_ler(b.m_ler),

56 m_vertex(b.m_vertex), m_validFlag(b.m_validFlag), m_generationFlags(b.m_generationFlags) {}

Belle2::MCInitialParticles::m_generationFlags

int m_generationFlags

Flags to be used when generating events.

Definition: MCInitialParticles.h:250

Belle2::MCInitialParticles::m_ler

ROOT::Math::PxPyPzEVector m_ler

LER 4vector.

Definition: MCInitialParticles.h:231

Belle2::MCInitialParticles::m_her

ROOT::Math::PxPyPzEVector m_her

HER 4vector.

Definition: MCInitialParticles.h:229

Belle2::MCInitialParticles::m_vertex

ROOT::Math::XYZVector m_vertex

collision position

Definition: MCInitialParticles.h:233

Belle2::MCInitialParticles::m_validFlag

bool m_validFlag

transient

Definition: MCInitialParticles.h:245

◆ ~MCInitialParticles()

virtual ~MCInitialParticles ( )

inlinevirtual

Free memory of the LorentzRotation if it was created.

Definition at line 89 of file MCInitialParticles.h.

89{ resetBoost(); }

Belle2::MCInitialParticles::resetBoost

void resetBoost()

Reset cached transformations after changing parameters.

Definition: MCInitialParticles.h:290

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;
}

◆ getBoostedHER()

ROOT::Math::PxPyPzEVector getBoostedHER ( ) const

inline

Get the 4-vector of electron beam in CM system obtained by pure boost.

Definition at line 185 of file MCInitialParticles.h.

185{ calculateBoost(); return m_boostedHER; }

Belle2::MCInitialParticles::m_boostedHER

ROOT::Math::PxPyPzEVector m_boostedHER

transient

Definition: MCInitialParticles.h:243

Belle2::MCInitialParticles::calculateBoost

void calculateBoost() const

Calculate the Lorentz transformations LAB->CMS & CMS->LAB if necessary.

Definition: MCInitialParticles.h:258

◆ getBoostVector()

ROOT::Math::XYZVector getBoostVector ( ) const

inline

Get the boost vector (velocity of system produced in the collision)

Definition at line 182 of file MCInitialParticles.h.

182{ calculateBoost(); return -(m_her + m_ler).BoostToCM(); }

◆ getCMSToLab()

const ROOT::Math::LorentzRotation & getCMSToLab ( ) const

inline

Return the LorentzRotation to convert from CMS to lab frame.

Definition at line 194 of file MCInitialParticles.h.

    {
      calculateBoost(); return *m_CMSToLab;
    }

◆ getEnergy()

double getEnergy ( ) const

inline

Get the actual collision energy (in lab system)

Definition at line 176 of file MCInitialParticles.h.

176{ return (m_her + m_ler).E(); }

◆ getGenerationFlags()

int getGenerationFlags ( ) const

inline

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

Definition at line 203 of file MCInitialParticles.h.

203{ return m_generationFlags; }

◆ 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.

{
  std::string flags = "";
  const std::vector<std::pair<int, std::string>> flagvalues{
    {c_generateCMS, "generateCMS"},
    {c_smearBeamEnergy, "smearBeamEnergy"},
    {c_smearBeamDirection, "smearBeamDirection"},
    {c_smearVertex, "smearVertex"}
  };
  for (auto& i : flagvalues) {
    if (hasGenerationFlags(i.first)) {
      if (flags.size() > 0) flags += separator;
      flags += i.second;
    }
  }
  return flags;
}

◆ getHER()

const ROOT::Math::PxPyPzEVector & getHER ( ) const

inline

Get 4vector of the high energy beam.

Definition at line 164 of file MCInitialParticles.h.

164{ return m_her; }

◆ getLabToCMS()

const ROOT::Math::LorentzRotation & getLabToCMS ( ) const

inline

Return the LorentzRotation to convert from lab to CMS frame.

Definition at line 188 of file MCInitialParticles.h.

    {
      calculateBoost(); return *m_labToCMS;
    }

◆ getLER()

const ROOT::Math::PxPyPzEVector & getLER ( ) const

inline

Get 4vector of the low energy beam.

Definition at line 167 of file MCInitialParticles.h.

167{ return m_ler; }

◆ getMass()

double getMass ( ) const

inline

Get the invariant mass of the collision (= energy in CMS)

Definition at line 179 of file MCInitialParticles.h.

179{ calculateBoost(); return m_invariantMass; }

Belle2::MCInitialParticles::m_invariantMass

double m_invariantMass

transient

Definition: MCInitialParticles.h:241

◆ getTime()

double getTime ( ) const

inline

Get collision time.

Definition at line 173 of file MCInitialParticles.h.

173{return m_time;}

Belle2::MCInitialParticles::m_time

double m_time

collision time

Definition: MCInitialParticles.h:235

◆ getValidFlag()

bool getValidFlag ( ) const

inline

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

Definition at line 200 of file MCInitialParticles.h.

200{ return m_validFlag; }

◆ getVertex()

const ROOT::Math::XYZVector & getVertex ( ) const

inline

Get the position of the collision.

Definition at line 170 of file MCInitialParticles.h.

170{ return m_vertex; }

◆ hasGenerationFlags()

bool hasGenerationFlags ( int flags ) const

inline

Check if a certain set of EGenerationFlags is set.

Definition at line 206 of file MCInitialParticles.h.

206{ return (m_generationFlags & flags) == flags; }

◆ operator=()

MCInitialParticles & operator= ( const MCInitialParticles & b )

inline

Assignment operator.

Definition at line 59 of file MCInitialParticles.h.

    {
      m_her = b.m_her; m_ler = b.m_ler; m_vertex = b.m_vertex;
      m_validFlag = b.m_validFlag; m_generationFlags = b.m_generationFlags;
      resetBoost();
      return *this;
    }

◆ operator==()

bool operator== ( const MCInitialParticles & b ) const

inline

Equality operator.

Definition at line 68 of file MCInitialParticles.h.

    {
      // FIXME: sin(x) returns slightly different values on
      // different platforms in some cases so we cannot just do an equality
      // comparison. We need to do this more elegantly, this is just for
      // testing if it solves all problems
#if defined(MCP_DBL_CMP) || defined(MCP_VEC3_CMP) || defined(MCP_VEC4_CMP)
#error Macro already defined, cannot continue
#endif
#define MCP_DBL_CMP(a,b,x) ((a.X()==b.X())||(std::abs(a.X()-b.X())<1e-10))
#define MCP_VEC3_CMP(a,b) (MCP_DBL_CMP(a,b,X) && MCP_DBL_CMP(a,b,Y) && MCP_DBL_CMP(a,b,Z))
#define MCP_VEC4_CMP(a,b) (MCP_VEC3_CMP(a,b) && MCP_DBL_CMP(a,b,E))
      return MCP_VEC4_CMP(m_her, b.m_her) && MCP_VEC4_CMP(m_ler, b.m_ler) && MCP_VEC3_CMP(m_vertex, b.m_vertex)
             && m_validFlag == b.m_validFlag &&
             m_generationFlags == b.m_generationFlags;
#undef MCP_DBL_CMP
#undef MCP_VEC3_CMP
#undef MCP_VEC4_CMP
    }

◆ 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.

    {
      m_her = her;
      m_ler = ler;
      m_vertex = vertex;
      m_validFlag = true;
      resetBoost();
    }

◆ 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.

    {
      if (m_labToCMS) delete m_labToCMS;
      if (m_CMSToLab) delete m_CMSToLab;
 
      m_invariantMass = Ecms;
      m_CMSToLab      = new ROOT::Math::LorentzRotation();
      m_labToCMS      = new ROOT::Math::LorentzRotation();
      *m_CMSToLab     = cmsToLab(bX, bY, bZ, angleXZ, angleYZ);
      *m_labToCMS     = m_CMSToLab->Inverse();
 
      const double me = Const::electron.getMass();
      double p = sqrt(Ecms * Ecms / 4 - me * me);
      m_her = (*m_CMSToLab) * ROOT::Math::PxPyPzEVector(0.0, 0.0,  p, Ecms / 2);
      m_ler = (*m_CMSToLab) * ROOT::Math::PxPyPzEVector(0.0, 0.0, -p, Ecms / 2);
 
      m_vertex = vertex;
      m_validFlag = true;
    }

◆ setGenerationFlags()

virtual void setGenerationFlags ( int flags )

inlinevirtual

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

Reimplemented in BeamParameters.

Definition at line 161 of file MCInitialParticles.h.

161{ m_generationFlags = flags; }

◆ setHER()

void setHER ( const ROOT::Math::PxPyPzEVector & her )

inline

Set the High Energy Beam 4-momentum.

Definition at line 138 of file MCInitialParticles.h.

    {
      m_her = her;
      resetBoost();
    }

◆ setLER()

void setLER ( const ROOT::Math::PxPyPzEVector & ler )

inline

Set the Low Energy Beam 4-momentum.

Definition at line 145 of file MCInitialParticles.h.

    {
      m_ler = ler;
      resetBoost();
    }

◆ setTime()

void setTime ( double time )

inline

Set collision time.

Definition at line 158 of file MCInitialParticles.h.

158{m_time = time;}

◆ setVertex()

void setVertex ( const ROOT::Math::XYZVector & vertex )

inline

Set the vertex position.

Definition at line 152 of file MCInitialParticles.h.

    {
      m_vertex = vertex;
    }

Member Data Documentation

◆ m_boostedHER

ROOT::Math::PxPyPzEVector m_boostedHER

mutableprivate

transient

HER 4-momentum in CM frame obtained by pure boost (calculated on first use, not saved to file)

Definition at line 243 of file MCInitialParticles.h.

◆ 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 239 of file MCInitialParticles.h.

◆ m_generationFlags

int m_generationFlags {0}

protected

Flags to be used when generating events.

Definition at line 250 of file MCInitialParticles.h.

◆ m_her

ROOT::Math::PxPyPzEVector m_her

private

HER 4vector.

Definition at line 229 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 241 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 237 of file MCInitialParticles.h.

◆ m_ler

ROOT::Math::PxPyPzEVector m_ler

private

LER 4vector.

Definition at line 231 of file MCInitialParticles.h.

◆ m_time

double m_time = 0

private

collision time

Definition at line 235 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 245 of file MCInitialParticles.h.

◆ m_vertex

ROOT::Math::XYZVector m_vertex

private

collision position

Definition at line 233 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

Constructor & Destructor Documentation

◆ MCInitialParticles() [1/2]

◆ MCInitialParticles() [2/2]

◆ ~MCInitialParticles()

Member Function Documentation

◆ cmsToLab()

◆ getBoostedHER()

◆ getBoostVector()

◆ getCMSToLab()

◆ getEnergy()

◆ getGenerationFlags()

◆ getGenerationFlagString()

◆ getHER()

◆ getLabToCMS()

◆ getLER()

◆ getMass()

◆ getTime()

◆ getValidFlag()

◆ getVertex()

◆ hasGenerationFlags()

◆ operator=()

◆ operator==()

◆ set()

◆ setByLorentzTransformation()

◆ setGenerationFlags()

◆ setHER()

◆ setLER()

◆ setTime()

◆ setVertex()

Member Data Documentation

◆ m_boostedHER

◆ m_CMSToLab

◆ m_generationFlags

◆ m_her

◆ m_invariantMass

◆ m_labToCMS

◆ m_ler

◆ m_time

◆ m_validFlag

◆ m_vertex