DireSplittingQCD Class Reference

Inheritance diagram for DireSplittingQCD:

Public Member Functions
	DireSplittingQCD (string idIn, int softRS, Settings *settings, ParticleData *particleData, Rndm *rndm, BeamParticle *beamA, BeamParticle *beamB, CoupSM *coupSM, Info *info, DireInfo *direInfo)
	Constructor and destructor.
void	init ()
double	getNF (double pT2)
	AUXILIARY FUNCTIONS. More...
double	GammaQCD2 (double NF=5.)
double	GammaQCD3 (double NF=5.)
double	betaQCD0 (double NF=5.)
double	betaQCD1 (double NF=5.)
double	betaQCD2 (double NF=5.)
double	as2Pi (double pT2, int orderNow=-1, double renormMultFacNow=-1.)
double	softRescaleInt (int order)
double	softRescaleDiff (int order, double pT2, double renormMultFacNow=-1.)
double	beta0Endpoint (int order, double m2dip, double pT2, double z, double renormMultFacNow=-1.)
double	polevl (double x, double *coef, int N)
	Helper function to calculate dilogarithm.
double	DiLog (double x)
	Function to calculate dilogarithm.
vector< int >	sharedColor (const Event &event, int iRad, int iRec)
bool	hasSharedColor (const Event &event, int iRad, int iRec)
int	findCol (int col, vector< int > iExc, const Event &, int type)
bool	useFastFunctions ()
virtual vector< int >	radAndEmt (int idDaughter, int)
virtual bool	isPartial ()
virtual int	couplingType (int, int)
virtual double	coupling (double z, double pT2, double m2dip, double renormMultFacNow=-1., pair< int, bool > radBef=pair< int, bool >(), pair< int, bool > recBef=pair< int, bool >())
virtual double	couplingScale2 (double z, double pT2, double m2dip, pair< int, bool > radBef, pair< int, bool > recBef)
virtual double	getJacobian (const Event &=Event(), PartonSystems *partonSystems=0)
virtual unordered_map< string, double >	getPhasespaceVars (const Event &=Event(), PartonSystems *=0)
double	sCoef (int powz)
double	sExp (int powz)
double	kCoef (int powz)
double	kExp (int powz)
double	cCoef (int powz)
double	cExp (int powz)
double	fCoef ()
bool	hasMECBef (const Event &state, double pT2)
bool	hasMECAft (const Event &state, double pT2)
Public Member Functions inherited from DireSplitting
	DireSplitting ()
	Constructor and destructor.
	DireSplitting (string idIn, int softRS, Settings *settings, ParticleData *particleData, Rndm *rndm, BeamParticle *beamA, BeamParticle *beamB, CoupSM *coupSMPtrIn, Info *infoPtrIn, DireInfo *direInfo)
void	init ()
	The Splitting class.
bool	is (ulong pattern)
string	name ()
virtual bool	canRadiate (const Event &, pair< int, int >, unordered_map< string, bool >=unordered_map< string, bool >(), Settings *=NULL, PartonSystems *=NULL, BeamParticle *=NULL)
virtual bool	aboveCutoff (double, const Particle &, const Particle &, int, PartonSystems *=NULL)
	Discard below the cut-off for the splitting.
virtual bool	canRadiate (const Event &, int, int, Settings *=NULL, PartonSystems *=NULL, BeamParticle *=NULL)
virtual int	kinMap ()
virtual int	motherID (int)
	Return id of mother after splitting.
virtual int	sisterID (int)
	Return id of emission.
virtual vector< pair< int, int > >	radAndEmtCols (int, int, Event)
virtual bool	canUseForBranching ()
virtual int	nEmissions ()
virtual bool	swapRadEmt ()
virtual bool	isSymmetric (const Particle *=NULL, const Particle *=NULL)
virtual vector< int >	recPositions (const Event &, int, int)
virtual int	radBefID (int, int)
	Return id of recombined radiator (before splitting!)
virtual pair< int, int >	radBefCols (int, int, int, int)
	Return colours of recombined radiator (before splitting!)
virtual double	gaugeFactor (int, int)
	Return color factor for splitting.
virtual double	symmetryFactor (int, int)
	Return symmetry factor for splitting.
virtual double	zSplit (double, double, double)
	Pick z for new splitting.
virtual double	overestimateInt (double, double, double, double, int=-1)
	New overestimates, z-integrated versions.
virtual double	overestimateDiff (double, double, int=-1)
	Return kernel for new splitting.
virtual double	getKernel (string="")
	Functions to store and retrieve all the variants of the kernel.
virtual unordered_map< string, double >	getKernelVals ()
virtual void	clearKernels ()
virtual bool	calc (const Event &=Event(), int=-1)
	Functions to calculate the kernel from SplitInfo information.
void	setTimesPtr (shared_ptr< DireTimes > fsrIn)
void	setTimesDecPtr (shared_ptr< DireTimes > fsrIn)
void	setSpacePtr (shared_ptr< DireSpace > isrIn)
virtual bool	allow_z_endpoint_for_kinematics ()
	Treatment of additional virtual corrections.
virtual bool	allow_pT2_endpoint_for_kinematics ()
virtual bool	allow_sai_endpoint_for_kinematics ()
virtual bool	allow_xa_endpoint_for_kinematics ()
virtual void	try_z_endpoint ()
	Functions to set if kernel should contribute to a kinematical endpoint.
virtual void	try_pT2_endpoint ()
virtual void	try_sai_endpoint ()
virtual void	try_xa_endpoint ()
virtual bool	is_z_endpoint ()
	Return endpoint information.
virtual bool	is_pT2_endpoint ()
virtual bool	is_sai_endpoint ()
virtual bool	is_xa_endpoint ()
virtual double	tdire_ff (double, double t, double)
	Functions to calculate Dire variables from the evolution variables.
virtual double	zdire_ff (double z, double, double)
virtual double	tdire_fi (double, double t, double)
virtual double	zdire_fi (double z, double, double)
virtual double	tdire_if (double, double t, double)
virtual double	zdire_if (double z, double, double)
virtual double	tdire_ii (double, double t, double)
virtual double	zdire_ii (double z, double, double)
virtual void	storeOverhead (double pT2, double x, int radid, int nf, double val)
virtual double	overhead (double pT2, int idd, int nf)

Public Attributes
double	CA
	VARIABLES.
double	TR
double	CF
double	pTmin
double	pT2minVariations
int	NF_qcd_fsr
int	orderSave
bool	usePDFalphas
bool	doVariations
bool	doCorrelations
bool	doMECs
double	alphaSorder
double	alphaS2pi
AlphaStrong	alphaS
int	asSchemeISR
int	asSchemeFSR
bool	useBackboneGluons
bool	doGeneralizedKernel
Public Attributes inherited from DireSplitting
double	renormMultFac
string	id
int	correctionOrder
Settings *	settingsPtr
ParticleData *	particleDataPtr
Rndm *	rndmPtr
BeamParticle *	beamAPtr
BeamParticle *	beamBPtr
CoupSM *	coupSMPtr
Info *	infoPtr
DireInfo *	direInfoPtr
bool	is_qcd
	Some short-cuts and string hashes to help avoid string comparisons.
bool	is_qed
bool	is_ewk
bool	is_fsr
bool	is_isr
bool	is_dire
ulong	nameHash
unordered_map< string, double >	kernelVals
DireSplitInfo	splitInfo
shared_ptr< DireSpace >	isr
shared_ptr< DireTimes >	fsr
shared_ptr< DireTimes >	fsrDec
multimap< double, OverheadInfo >	overhead_map

Static Public Attributes
static const double	SMALL_TEVOL = 2.0
	The SplittingQCD class.

Member Function Documentation

double as2Pi	(	double	pT2,
		int	orderNow = -1,
		double	renormMultFacNow = -1.
	)

Function to calculate the correct running coupling/2*Pi value, including renormalisation scale variations + threshold matching.

Function to calculate the correct alphaS/2*Pi value, including renormalisation scale variations + threshold matching.

Get beam for PDF alphaS, if necessary.

Get alphaS(k*pT^2) and subtractions.

Now find the necessary thresholds so that alphaS can be matched correctly.

Done.

double beta0Endpoint	(	int	order,
		double	m2dip,
		double	pT2,
		double	z,
		double	renormMultFacNow = -1.
	)

No explicit beta0-endpoint for inclusive NLO.

virtual double coupling ( double  , double  , double  , double  = -1., pair< int, bool >  = pair<int,bool>(), pair< int, bool >  = pair<int,bool>()  )

inlinevirtual

Return the value of the coupling that should be used for this branching. Note that the last input allows easy access to the PS evolution variable. return values -1 –> Coupling value not defined. double > 0 –> Value to be used for this branching.

Return coupling. Set up such the argument is NOT RESCALED in as2Pi function - rather guarantee that INPUT pT2/scale has desired value.

Reimplemented from DireSplitting.

Reimplemented in Dire_fsr_ew_H2GG, Dire_fsr_ew_H2AA, DireSplittingU1new, DireSplittingEW, and DireSplittingQED.

virtual int couplingType ( int  , int    )

inlinevirtual

Return an identifier for the interaction that causes the branching. return values -1 –> Type not defined. 1 –> QCD splitting (i.e. proportional to alphaS) 2 –> QED splitting (i.e. proportional to alphaEM) 3 –> EW splitting (i.e. proportional to sinThetaW) 4 –> Yukawa splitting (i.e. proportional to y)

Reimplemented from DireSplitting.

Reimplemented in Dire_fsr_ew_H2GG, Dire_fsr_ew_H2AA, DireSplittingU1new, DireSplittingEW, and DireSplittingQED.

int findCol	(	int	col,
		vector< int >	iExc,
		const Event &	event,
		int	type
	)

Search event record for matching colour & anticolour

Skip if this index is excluded.

Search event record for matching colour & anticolour

Skip if this index is excluded.

Check incoming

if no matching colour / anticolour has been found, return false

double getJacobian ( const Event &  state = Event(), PartonSystems *  partonSystems = 0  )

virtual

Functions that allow different ordering variables for emissions. Note: Only works after splitInfo has been properly filled.

Read all splitting variables.

Final-final jacobian.

Recalculate the kinematicaly available dipole mass.

Pick remaining variables for 1->3 splitting.

Calculate CS variables and scaled masses.

Calculate Jacobian.

Jacobian for 1->3 splittings, in CS variables.

Jacobian for competing steps, i.e. applied to over-all splitting rate.

Additional jacobian for non-competing steps.

Additional factor from massive propagator.

Done.

Final-initial jacobian

Recalculate the kinematicaly available dipole mass.

Get momentum of other beam, since this might be needed to calculate the Jacobian.

Recalculate the kinematicaly available dipole mass. Calculate CS variables.

Jacobian for 1->2 splittings, in CS variables.

Jacobian for 1->3 splittings, in CS variables.

Jacobian for competing steps, i.e. applied to over-all splitting rate.

Calculate the partonic eCM before the splitting.

Now construct the new recoiler momentum.

Calculate the partonic eCM after the splitting.

Calculate Jacobian.

Additional jacobian for non-competing steps.

Extra correction from massless to massive propagator.

Initial-final jacobian

Pick remaining variables for 1->3 splitting.

Get momentum of other beam, since this might be needed to calculate the Jacobian.

Jacobian for 1->3 splittings, in CS variables.

Construnct the new initial state momentum, as needed to calculate the Jacobian.

sHat after emission depends on the recoil scheme if the incoming particles have non-zero mass. Local scheme.

Get transverse and parallel vectors.

Calculate derived variables.

Construct radiator after branching.

Now get changed eCM.

Global scheme.

Construct radiator after branching. Simple massless case.

Get dipole 4-momentum.

Calculate derived variables.

Now construct recoiler in lab frame.

Construct left-over dipole momentum by momentum conservation.

Set up kT vector by using two perpendicular four-vectors.

Construct new emission momentum.

Contruct radiator momentum by momentum conservation.

Now get changed eCM.

Now calculate Jacobian.

Additional jacobian for non-competing steps.

Additional factor from massive propagator.

Multiply with Jacobian.

Initial-initial jacobian

Pick remaining variables for 1->3 splitting.

Jacobian for 1->3 splittings, in CS variables.

Calculate Jacobian.

Additional factor from massive propagator.

Reimplemented from DireSplitting.

double getNF

(

double

pT2

)

AUXILIARY FUNCTIONS.

Auxiliary function to get number of flavours.

Get current number of flavours.

unordered_map< string, double > getPhasespaceVars ( const Event &  state = Event(), PartonSystems *  = 0  )

virtual

Function to convert ordering variables etc. to the phase space variables pT2 (in Dire default definition), z (in Dire default definition), sai (in Dire default definition) and xa (in Dire default definition).

Read all splitting variables.

Now construct Bjorken-x of initial-state after branching, as is necessary to attach PDF ratios.

Final-initial

Recalculate the kinematicaly available dipole mass.

Recalculate the kinematicaly available dipole mass. Calculate CS variables.

Initial-final

Calculate CS variables.

Initial-initial

Adjust the dipole kinematical mass to accomodate masses after branching.

Calculate CS variables.

1->3 splittings, in CS variables.

Pick remaining variables for 1->3 splitting.

Done.

Reimplemented from DireSplitting.

void init

(

)

Colour factors.

Parameters of alphaS.

Initialize alphaS.

Set up alphaS

virtual vector<int> radAndEmt ( int  , int    )

inlinevirtual

Return a pair of ids for the radiator and emission after the splitting.

Reimplemented from DireSplitting.

Reimplemented in Dire_fsr_qcd_G2Gqqbar, Dire_fsr_u1new_A2FF, Dire_fsr_qed_A2FF, Dire_fsr_qcd_Q2Qqqbar, Dire_fsr_qcd_G2GGG, Dire_fsr_qcd_Q2QGG, DireSplittingQED, DireSplittingU1new, and DireSplittingEW.

double softRescaleDiff	(	int	order,
		double	pT2,
		double	renormMultFacNow = -1.
	)

Get alphaS and number of flavours, attach cusp factors.

No inclusive cusp rescaling for differential NLO.

double softRescaleInt

(

int

order

)

No inclusive cusp rescaling for differential NLO.

Member Data Documentation

int asSchemeISR

Function determining the argument of the running coupling based on the splitting variables. Current default: Evolution variable. DireTimes:alphasScheme = 0 : default DireTimes:alphasScheme = 1 : collinear kinematic kT for all splittings involving incoming particles. DireTimes:alphasScheme = 2 : eikonal factor sij*sjk/sik

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

• include/Pythia8/DireSplittingsQCD.h
• src/DireSplittingsQCD.cc