TopThreshold Class Reference

#include <SigmaQCD.h>

Public Member Functions
	TopThreshold ()
	Trivial constructor and destructor.
void	setup (int topModelIn, double mtIn, double gammatIn, double thresholdWidthIn, double singletFracIn, int alphasOrder, double alphasValue)
	Initialization setup - read in necessary settings. More...
double	multiplySigmaBy (bool inInit, double mHat, double m3, double m4, double eThr)
	Cross section enhancement factor, combined. More...
double	imGreenSin (double eNow, double mtNow)
	Imaginary part of Green's function for singlet state. More...
double	imGreenOct (double eNow, double mtNow)
	Imaginary part of Green's function for octet state. More...

Detailed Description

Auxiliary class for top threshold corrections, based on V. Fadin, V. Khoze and T. Sjostrand, Z. Phys. C48 (1990) 613.

Member Function Documentation

double imGreenOct	(	double	eNow,
		double	mtNow
	)

Imaginary part of Green's function for octet state.

Basic expressions.

Sum over resonance contributions.

Combine with non-resonant terms and done.

double imGreenSin	(	double	eNow,
		double	mtNow
	)

Imaginary part of Green's function for singlet state.

Basic expressions.

Sum over resonance contributions.

Combine with non-resonant terms and done.

double multiplySigmaBy	(	bool	inInit,
		double	mHat,
		double	m3,
		double	m4,
		double	eThr
	)

Cross section enhancement factor, combined.

Cross section enhancement factor.

No rescaling where not defined.

Calculate key kinematics variables.

alpha_strong value.

Initial values.

Coulomb threshold factors for attractive (singlet) and repulsive (octet).

Green's function factors for attractive (singlet) and repulsive (octet). Above threshold region transition to Coulomb.

Mirror Green's function contribution E < 0 to E > 0. Below threshold region transition to 0.

During initialization need to ensure that cross section does not vanish.

Proper below-threshold contribution. Again transition to zero.

Mix of attractive and repulsive channels.

Since the threshold cross section contains a beta factor this must be removed in the final answer.

void setup	(	int	topModelIn,
		double	mtIn,
		double	gammatIn,
		double	thrWidthIn,
		double	singletFracIn,
		int	alphasOrder,
		double	alphasValue
	)

Initialization setup - read in necessary settings.

TopThreshold. Auxiliary class to Sigma2gg2QQbar and Sigma2qqbar2QQbar, which allows simulation of top threshold enhancement factors according to V. Fadin, V. Khoze and T. Sjostrand, Z. Phys. C48 (1990) 613.

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

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