DGLAP Class Reference

A class containing DGLAP splitting functions for limit checking. More...

#include <VinciaAntennaFunctions.h>

Public Member Functions
	DGLAP ()
	Constructor.
double	Pg2gg (double z, int hA=9, int hB=9, int hC=9)
	DGLAP splitting functions. More...
double	Pg2qq (double z, int hA=9, int hB=9, int hC=9, double mu=0.)
double	Pq2qg (double z, int hA=9, int hB=9, int hC=9, double mu=0.)
double	Pq2gq (double z, int hA=9, int hB=9, int hC=9, double mu=0.)
double	Pg2qq (double z, double mu)
	Wrappers to get unpolarized massive Altarelli-Pariis kernels (mu = m/Q).
double	Pq2qg (double z, double mu)
double	Pq2gq (double z, double mu)
double	Pg2ggLin (double z, int polA=9, int polB=9, int polC=9)
	Pg2ggLin, written without factor 2 normalization convention. More...
double	Pg2qqLin (double z, int polA=9, int hB=9, int hC=9, double mu=0.)
double	Pq2qgLin (double z, int hA=9, int hB=9, int polC=9, double mu=0.)
double	Pq2gqLin (double z, int hA=9, int polB=9, int hC=9, double mu=0.)

Detailed Description

A class containing DGLAP splitting functions for limit checking.

Member Function Documentation

double Pg2gg	(	double	z,
		int	hA = 9,
		int	hB = 9,
		int	hC = 9
	)

DGLAP splitting functions.

Helicity-dependent Altarelli-Parisi kernels (mu = m/Q). Note, Pg2gg is written with standard factor 2 normalization convention.

DGLAP splitting kernels with helicity-dependence (from Larkoski, Peskin, http:///arxiv.org/abs/arXiv:0908.2450). Note, Pg2gg is written with the standard factor 2 normalization convention and gives a factor 2 difference with respect PYTHIA FSR. The difference is related to whether P is interpreted as the probability for gluon A to branch to BC (without factor 2), or as the probability for gluon B to have originated from A (with factor 2). Both quarks and gluons have definite helicities: 9: unpolarized +1: right-handed -1: left-handed where z is momentum fraction taken by B in A -> BC. Pg2gg, written with the standard factor 2 normalization convention.

If A unpolarized, treat as unpolarized.

Expressions coded for hA = 1. Flip helicities if hA = -1.

double Pg2ggLin	(	double	z,
		int	polA = 9,
		int	polB = 9,
		int	polC = 9
	)

Pg2ggLin, written without factor 2 normalization convention.

Altarelli-Parisi kernels with linear in/out polarizations for gluons: pol = +1 for in-plane, -1 for out-of-plane.

DGLAP splitting kernels with polarization-dependence (from Ellis, Stirling, Webber) Gluons are plane polarized, quarks have helicities: 9: unpolarized +1: in plane / right-handed -1: out-of-plane / left-handed where z is momentum fraction taken by B in A -> BC.

If A unpolarized, treat as unpolarized.

A in-plane polarized.

A out-of-plane polarized.

double Pg2qq	(	double	z,
		int	hA = 9,
		int	hB = 9,
		int	hC = 9,
		double	mu2 = 0.
	)

Pg2qq, B is quark, C is antiquark. Note, mass corrections not implemented.

If A unpolarized, treat as unpolarized.

Preserve quark helicity.

Expressions coded for hA = 1. Flip helicities if hA = -1.

double Pg2qqLin	(	double	z,
		int	polA = 9,
		int	hB = 9,
		int	hC = 9,
		double	mu = 0.
	)

Pg2qqLin, B is quark, C is antiquark. Note, mass corrections not implemented.

If A unpolarized, treat as unpolarized.

Preserve quark helicity.

A in-plane polarized.

A out-of-plane polarized.

double Pq2gq	(	double	z,
		int	hA = 9,
		int	hB = 9,
		int	hC = 9,
		double	mu = 0.
	)

Pq2qg, B is gluon, C is quark. Note, mass corrections not implemented for polarised.

double Pq2gqLin	(	double	z,
		int	hA = 9,
		int	polB = 9,
		int	hC = 9,
		double	mu = 0.
	)

Pq2qgLin, B is gluon, C is quark. Note, mass corrections not implemented.

double Pq2qg	(	double	z,
		int	hA = 9,
		int	hB = 9,
		int	hC = 9,
		double	mu2 = 0.
	)

Pq2qg, B is quark, C is gluon. Note, mass corrections not implemented for polarised.

If A unpolarized, treat as unpolarized.

Preserve quark helicity

Expressions coded for hA = +1. Flip helicities if hA = -1.

double Pq2qgLin	(	double	z,
		int	hA = 9,
		int	hB = 9,
		int	polC = 9,
		double	mu = 0.
	)

Pq2qgLin, B is quark, C is gluon. Note, mass corrections not implemented.

If A unpolarized, treat as unpolarized.

Preserve quark helicity.

Gluon polarized in plane.

Gluon polarized out of plane.

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

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