PYTHIA  8.303
Public Member Functions | List of all members
GQEmitII Class Reference

Class GQEmitII, initial-initial antenna function. More...

#include <VinciaAntennaFunctions.h>

Inheritance diagram for GQEmitII:
AntennaFunctionIX AntennaFunction

Public Member Functions

virtual string vinciaName () const
 Names (remember to redefine both for each inherited class).
 
virtual int idA () const
 Parton types AB -> 0a 1j 2b with A,B,a,b initial and j final.
 
virtual int idB () const
 
virtual int id0 () const
 
virtual int id1 () const
 
virtual int id2 () const
 
virtual double antFun (vector< double > invariants, vector< double > masses, vector< int > helBef, vector< int > helNew)
 The antenna function. More...
 
virtual double AltarelliParisi (vector< double > invariants, vector< double >, vector< int > helBef, vector< int > helNew)
 AP splitting kernel for collinear limit checks. More...
 
- Public Member Functions inherited from AntennaFunctionIX
virtual bool init ()
 Method to initialise (can be different than that of the base class). More...
 
virtual double zA (vector< double > invariants)
 Functions to get Altarelli-Parisi energy fractions.
 
virtual double zB (vector< double > invariants)
 
virtual bool isIIant ()
 Function to tell if this is an II antenna.
 
virtual bool check ()
 Function to check singularities, positivity, etc. More...
 
- Public Member Functions inherited from AntennaFunction
 AntennaFunction ()=default
 Constructor.
 
virtual ~AntennaFunction ()
 Destructor.
 
virtual string baseName () const
 Construct baseName from idA, idB, and id1.
 
virtual string humanName () const
 Wrapper that can modify baseName to more human readable form if required.
 
virtual void initMasses (vector< double > *masses)
 Method to intialise mass values.
 
virtual int initHel (vector< int > *helBef, vector< int > *helNew)
 Method to initialise internal helicity variables. More...
 
double antFun (vector< double > invariants, vector< double > masses)
 Wrapper for helicity-summed/averaged antenna function.
 
double antFun (vector< double > invariants)
 Wrapper for massless, helicity-summed/averaged antenna function.
 
double AltarelliParisi (vector< double > invariants, vector< double > masses)
 Wrapper without helicity assignments.
 
double AltarelliParisi (vector< double > invariants)
 Wrapper for massless helicity-summed/averaged DGLAP kernels.
 
void initPtr (Info *infoPtrIn, DGLAP *dglapPtrIn)
 Initialize pointers. More...
 
double chargeFac ()
 Get parameters.
 
int kineMap ()
 
double alpha ()
 
double sectorDamp ()
 
double zA (vector< double > invariants)
 Functions to get Altarelli-Parisi energy fractions from invariants.
 
double zB (vector< double > invariants)
 
string id2str (int id) const
 Auxiliary function to translate an ID code to a string. More...
 

Additional Inherited Members

- Protected Attributes inherited from AntennaFunction
bool isInitPtr {false}
 Is initialized.
 
bool isInit {false}
 
double chargeFacSav {0.0}
 Charge factor, kinematics map, and subleading-colour treatment.
 
int kineMapSav {0}
 
int modeSLC {-1}
 
bool sectorShower {false}
 
double alphaSav {0.0}
 The alpha collinear-partitioning parameter.
 
double sectorDampSav {0.0}
 The sector-shower collinear dampening parameter.
 
double term {}
 Shorthand for commonly used variable(s).
 
double preFacFiniteTermSav {0.0}
 
double antMinSav {0.0}
 
bool isMinVar {}
 
double mi {0.0}
 Variables for internal storage of masses and helicities.
 
double mj {0.0}
 
double mk {0.0}
 
int hA {9}
 
int hB {9}
 
int hi {9}
 
int hj {9}
 
int hk {9}
 
map< int, bool > LH {{9, true}, {1, false}, {-1, true}}
 
map< int, bool > RH {{9, true}, {1, true}, {-1, false}}
 
int verbose {1}
 Verbosity level.
 
InfoinfoPtr {}
 Pointers to Pythia8 classes.
 
ParticleDataparticleDataPtr {}
 
SettingssettingsPtr {}
 
RndmrndmPtr {}
 
DGLAPdglapPtr {}
 Pointer to VINCIA DGLAP class.
 
vector< double > mDum {0, 0, 0, 0}
 Dummy vectors.
 
vector< int > hDum {9, 9, 9, 9}
 

Detailed Description

Class GQEmitII, initial-initial antenna function.

Member Function Documentation

double AltarelliParisi ( vector< double >  invariants,
vector< double >  ,
vector< int >  helBef,
vector< int >  helNew 
)
virtual

AP splitting kernel for collinear limit checks.

AP splitting kernel for collinear limit checks, P(z)/Q2.

Sanity check. Require positive invariants.

Sanity check. Require positive invariants.

Using smaller invariant for collinear limit

Collinear to initial gluon.

AP uses alpha/2pi * CA, ant uses alpha/4pi * CA, with CA = 3.

gluon appears in 2 ants, hence ant reproduces half of AP.

Collinear to initial quark.

AP uses alpha/2pi * CF, ant uses alpha/4pi * 2CF, with CF = 4/3.

ant with quark reproduces full AP.

Implements AntennaFunction.

double antFun ( vector< double >  invariants,
vector< double >  masses,
vector< int >  helBef,
vector< int >  helNew 
)
virtual

The antenna function.

Class GQEmitII, initial-initial antenna function.

The antenna function [GeV^-2].

Invariants and helicities.

Sanity check. Require positive invariants.

Initialise masses and helicities. Return 0 for unphysical helicities.

Shorthands

Mass corrections.

Do helicity sum.

(++ and –) parents.

++ > +++ && – > — antennae (MHV).

++ > +-+ && – > -+- antennae (NMHV).

++ > –+ && – > ++- antennae.

++ > +– && – > -++ antennae (massive helicity flip).

(+- and -+) parents.

+- > ++- && -+ > –+ antennae.

+- > +– && -+ > -++ antennae.

+- > — && -+ > +++ antennae.

+- > +++ && -+ > — antennae (massive helicity flip).

Subleading colour correction.

Return helicity sum, averaged over initial helicities.

Implements AntennaFunction.


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