apfel::AlphaQED Class Reference

The AlphaQED is a specialization class of the MatchedEvolution class for the computation of the QED coupling running. More...

#include <alphaqed.h>

Inheritance diagram for apfel::AlphaQED:

Public Member Functions
double	MatchObject (bool const &Up, int const &nfl, double const &Coup) const
	Function for the computation of the matching.
double	Derivative (int const &nfl, double const &, double const &a) const
	Function that returns QED function.
double	betaQED (int const &pt, int const &nf, int const &nl) const
	Function for the computation of the single coefficients of the expansion of the QED function.
Constructors
List of constructors.
	AlphaQED ()=delete
	AlphaQED (double const &AlphaRef, double const &MuRef, std::vector< double > const &LeptThresholds, std::vector< double > const &QuarkThresholds, int const &pt, int const &nsteps=10)
	AlphaQED constructor.
Public Member Functions inherited from apfel::MatchedEvolution< double >
	MatchedEvolution ()=delete
	MatchedEvolution (double const &ObjRef, double const &MuRef, std::vector< double > const &Thresholds, int const &nsteps=10)
	The MatchedEvolution constructor.
virtual	~MatchedEvolution ()=default
virtual double	EvolveObject (int const &nf, double const &t0, double const &t1, double const &Obj0) const
	Virtual function for the computation of the evolution.
double	Evaluate (double const &mu) const
	Function that returns the evolved object.
double	GetObjectRef () const
	Function that returns the reference value of the object.
double	GetMuRef () const
	Function that returns the reference scale.
std::vector< double >	GetThresholds () const
	Function that returns the values of the thresholds.
int	GetNumberOfSteps () const
	Function that returns the number of steps.
void	SetObjectRef (double ObjRef)
	Function that sets the reference value of the object.
void	SetMuRef (double const &MuRef)
	Function that sets the reference scale.
void	SetNumberOfSteps (int const &nsteps)
	Function that sets the number of steps of the RK algorithm.

Private Attributes
int const	_pt
	Perturbative order.
std::function< double(int const &, double const &)>	_BetaFunction
	Beta function.

Additional Inherited Members
Protected Attributes inherited from apfel::MatchedEvolution< double >
double	_ObjRef
double	_MuRef
double	_MuRef2
double	_LogMuRef2
std::vector< double >	_Thresholds
int	_nsteps
std::vector< double >	_Thresholds2
std::vector< double >	_LogThresholds2

Detailed Description

The AlphaQED is a specialization class of the MatchedEvolution class for the computation of the QED coupling running.

Examples

coupling_test.cc, and siaxsec_test.cc.

Constructor & Destructor Documentation

AlphaQED() [1/2]

apfel::AlphaQED::AlphaQED ( )

delete

AlphaQED() [2/2]

apfel::AlphaQED::AlphaQED	(	double const &	AlphaRef,
		double const &	MuRef,
		std::vector< double > const &	LeptThresholds,
		std::vector< double > const &	QuarkThresholds,
		int const &	pt,
		int const &	nsteps = 10 )

AlphaQED constructor.

Parameters

AlphaRef	the reference value of the coupling
MuRef	the reference value of the scale
QuarkThresholds	vector of quark thresholds
LeptThresholds	vector of charged-lepton thresholds
pt	perturbative order
nsteps	number of steps of the ODE solver

Member Function Documentation

betaQED()

double apfel::AlphaQED::betaQED	(	int const &	pt,
		int const &	nf,
		int const &	nl ) const

Function for the computation of the single coefficients of the expansion of the QED function.

Parameters

pt	perturbative order
nf	number of active quark flavours
nl	number of active charged leptons

Returns

The pt-th coefficient of the QED function.

Derivative()

double apfel::AlphaQED::Derivative ( int const & nfl, double const & , double const & a ) const

virtual

Function that returns QED function.

Parameters

nfl	total number of active flavours including both quarks and leptons
a	value of the coupling

Returns

The the value of the QED function

Implements apfel::MatchedEvolution< double >.

MatchObject()

double apfel::AlphaQED::MatchObject ( bool const & Up, int const & nfl, double const & Coup ) const

virtual

Function for the computation of the matching.

Parameters

Up	tells whether the matching is upward or not (downward)
nfl	total number of active flavours including both quarks and leptons
Coup	value of the coupling to be matched

Returns

The matched value of the strong coupling at the threshold

Note

This is a dummy function required only to instantiate the pure-virtual 'MatchObject' of the mother class 'MatchedEvolution': it always returns the input coupling. This means that the evolution is assumed to be continuos at the thresholds.

Implements apfel::MatchedEvolution< double >.

Member Data Documentation

_BetaFunction

std::function<double(int const&, double const&)> apfel::AlphaQED::_BetaFunction

private

Beta function.

_pt

int const apfel::AlphaQED::_pt

private

Perturbative order.

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

• /Users/vb262523/Codes/apfelxx/inc/apfel/alphaqed.h