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Herwig  7.1.4

This concrete class provides the definition of the pure virtual function value() and overestimateValue() for the strong coupling. More...

#include <ShowerAlphaQCD.h>

Inheritance diagram for Herwig::ShowerAlphaQCD:

Public Member Functions

 ShowerAlphaQCD ()
 The default constructor.
 
Energy lambdaQCD (unsigned int nf)
 Get the value of $\Lambda_{\rm QCd}$. More...
 
const vector< Energy > & quarkMasses () const
 Return the quark masses to be used; if not empty these masses should be considered instead of the ones set in the particle data objects.
 
virtual double value (const Energy2 scale) const
 Methods to return the coupling. More...
 
virtual double overestimateValue () const
 It returns the running coupling value evaluated at the input scale multiplied by the scale factor scaleFactor().
 
virtual double ratio (const Energy2 scale, double factor=1.) const
 Return the ratio of the coupling at the scale to the overestimated value.
 
virtual void initialize ()
 Initialize this coupling.
 
string value (string)
 A command to initialize the coupling and write its value at the scale given by the argument (in GeV)
 
string check (string args)
 Match thresholds and write alpha_s specified file; arguments are Q_low/GeV Q_high/GeV n_steps filename.
 
Functions used by the persistent I/O system.
void persistentOutput (PersistentOStream &os) const
 Function used to write out object persistently. More...
 
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently. More...
 
- Public Member Functions inherited from Herwig::ShowerAlpha
 ShowerAlpha ()
 The default constructor.
 
double scaleFactor () const
 It returns the factor that multiplies the scale argument, $\mu^2$, of the running coupling. More...
 
void persistentOutput (PersistentOStream &os) const
 Function used to write out object persistently. More...
 
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently. More...
 
- Public Member Functions inherited from ThePEG::Interfaced
virtual bool defaultInit ()
 
PPtr getParticle (PID) const
 
PDPtr getParticleData (PID) const
 
bool used () const
 
void useMe () const
 
tEGPtr generator () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
PPtr getParticle (PID) const
 
PDPtr getParticleData (PID) const
 
bool used () const
 
void useMe () const
 
tEGPtr generator () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from ThePEG::InterfacedBase
string fullName () const
 
string name () const
 
string path () const
 
string comment () const
 
void setup (istream &is)
 
virtual void debugme () const
 
void update ()
 
void init ()
 
virtual bool preInitialize () const
 
void initrun ()
 
void finish ()
 
void touch ()
 
void reset ()
 
void clear ()
 
InitState state () const
 
bool locked () const
 
bool touched () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
void update ()
 
void init ()
 
virtual bool preInitialize () const
 
void initrun ()
 
void finish ()
 
void touch ()
 
void reset ()
 
void clear ()
 
InitState state () const
 
bool locked () const
 
bool touched () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from ThePEG::Base
void debug () const
 
- Public Member Functions inherited from ThePEG::Pointer::ReferenceCounted
CounterType referenceCount () const
 
- Public Member Functions inherited from ThePEG::Named
 Named (const string &newName=string())
 
const string & name () const
 
bool operator== (const Named &other) const
 
bool operator< (const Named &other) const
 

Static Public Member Functions

static void Init ()
 The standard Init function used to initialize the interfaces. More...
 
- Static Public Member Functions inherited from Herwig::ShowerAlpha
static void Init ()
 The standard Init function used to initialize the interfaces. More...
 
- Static Public Member Functions inherited from ThePEG::Interfaced
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::InterfacedBase
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::Base
static void Init ()
 

Protected Member Functions

Clone Methods.
virtual IBPtr clone () const
 Make a simple clone of this object. More...
 
virtual IBPtr fullclone () const
 Make a clone of this object, possibly modifying the cloned object to make it sane. More...
 
Standard Interfaced functions.
virtual void doinit ()
 Initialize this object after the setup phase before saving an EventGenerator to disk. More...
 
- Protected Member Functions inherited from ThePEG::Interfaced
void reporeg (IBPtr object, string name) const
 
bool setDefaultReference (PtrT &ptr, string classname, string objectname)
 
 Interfaced (const string &newName)
 
 Interfaced (const Interfaced &i)
 
void setGenerator (tEGPtr generator)
 
- Protected Member Functions inherited from ThePEG::InterfacedBase
 InterfacedBase (string newName)
 
 InterfacedBase (const InterfacedBase &i)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinitrun ()
 
virtual void dofinish ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinitrun ()
 
virtual void dofinish ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
- Protected Member Functions inherited from ThePEG::Pointer::ReferenceCounted
 ReferenceCounted (const ReferenceCounted &)
 
ReferenceCountedoperator= (const ReferenceCounted &)
 
 ReferenceCounted (const ReferenceCounted &)
 
ReferenceCountedoperator= (const ReferenceCounted &)
 
- Protected Member Functions inherited from ThePEG::Named
const Namedoperator= (const Named &other)
 
const string & name (const string &newName)
 

Private Member Functions

ShowerAlphaQCDoperator= (const ShowerAlphaQCD &)
 The assignment operator is private and must never be called. More...
 
double alphaS (Energy q, Energy lam, int nf) const
 Member functions which calculate the coupling. More...
 
double derivativealphaS (Energy q, Energy lam, int nf) const
 The derivative of $\alpha_S$ with respect to $\ln(Q^2/\Lambda^2)$. More...
 
Energy computeLambda (Energy match, double alpha, unsigned int nflav) const
 Compute the value of $Lambda$ needed to get the input value of the strong coupling at the scale given for the given number of flavours using the Newton-Raphson method. More...
 
pair< short, Energy > getLamNfTwoLoop (Energy q) const
 Return the value of $\Lambda$ and the number of flavours at the scale. More...
 

Private Attributes

Energy _qmin
 Minimum value of the scale.
 
int _asType
 Parameter controlling the behaviour of $\alpha_S$ in the non-perturbative region.
 
double _asMaxNP
 Another parameter, a possible (maximum) value of alpha in the non-perturbative region.
 
vector< Energy > _thresholds
 Thresholds for the different number of flavours.
 
vector< Energy > _lambda
 $\Lambda$ for the different number of flavours
 
unsigned int _nloop
 Option for the number of loops.
 
bool _lambdaopt
 Option for the translation between $\Lambda_{\bar{MS}}$ and $\Lambda_{\rm Herwig}$.
 
bool _thresopt
 Option for the threshold masses.
 
Energy _lambdain
 Input value of Lambda.
 
double _alphain
 Input value of $alpha_S(M_Z)$.
 
bool _inopt
 Option for the calculation of Lambda from input parameters.
 
double _tolerance
 Tolerance for discontinuities at the thresholds.
 
unsigned int _maxtry
 Maximum number of iterations for the Newton-Raphson method to converge.
 
double _alphamin
 The minimum value of the coupling.
 
double _val0
 Value of $\alpha_S$ at the minimum scale.
 
Energy _optInputScale
 An optional input scale to be used for the input alphas; if zero MZ will be used out of the particle data object.
 
vector< Energy > _quarkMasses
 The quark masses to be used; if not empty these masses should be considered instead of the ones set in the particle data objects.
 

Additional Inherited Members

- Public Types inherited from ThePEG::InterfacedBase
enum  InitState
 
- Public Types inherited from ThePEG::Pointer::ReferenceCounted
typedef unsigned int CounterType
 
- Public Attributes inherited from ThePEG::InterfacedBase
 initializing
 
 uninitialized
 
 initialized
 
 runready
 
- Public Attributes inherited from ThePEG::Pointer::ReferenceCounted
const unsigned long uniqueId
 
- Static Protected Member Functions inherited from ThePEG::Interfaced
static void registerRepository (IBPtr)
 
static void registerRepository (IBPtr, string newName)
 

Detailed Description

This concrete class provides the definition of the pure virtual function value() and overestimateValue() for the strong coupling.

A number of different options for the running of the coupling and its initial definition are supported.

See also
The interfaces defined for ShowerAlphaQCD.

Definition at line 33 of file ShowerAlphaQCD.h.

Member Function Documentation

◆ alphaS()

double Herwig::ShowerAlphaQCD::alphaS ( Energy  q,
Energy  lam,
int  nf 
) const
private

Member functions which calculate the coupling.

The 1,2,3-loop parametrization of $\alpha_S$.

Parameters
qThe scale
lam$\Lambda_{\rm QCD}$
nfThe number of flavours

◆ clone()

virtual IBPtr Herwig::ShowerAlphaQCD::clone ( ) const
protectedvirtual

Make a simple clone of this object.

Returns
a pointer to the new object.

Implements ThePEG::InterfacedBase.

◆ computeLambda()

Energy Herwig::ShowerAlphaQCD::computeLambda ( Energy  match,
double  alpha,
unsigned int  nflav 
) const
private

Compute the value of $Lambda$ needed to get the input value of the strong coupling at the scale given for the given number of flavours using the Newton-Raphson method.

Parameters
matchThe scale for the coupling
alphaThe input coupling
nflavThe number of flavours

◆ derivativealphaS()

double Herwig::ShowerAlphaQCD::derivativealphaS ( Energy  q,
Energy  lam,
int  nf 
) const
private

The derivative of $\alpha_S$ with respect to $\ln(Q^2/\Lambda^2)$.

Parameters
qThe scale
lam$\Lambda_{\rm QCD}$
nfThe number of flavours

◆ doinit()

virtual void Herwig::ShowerAlphaQCD::doinit ( )
protectedvirtual

Initialize this object after the setup phase before saving an EventGenerator to disk.

Exceptions
InitExceptionif object could not be initialized properly.

Reimplemented from ThePEG::InterfacedBase.

◆ fullclone()

virtual IBPtr Herwig::ShowerAlphaQCD::fullclone ( ) const
protectedvirtual

Make a clone of this object, possibly modifying the cloned object to make it sane.

Returns
a pointer to the new object.

Reimplemented from ThePEG::InterfacedBase.

◆ getLamNfTwoLoop()

pair<short, Energy> Herwig::ShowerAlphaQCD::getLamNfTwoLoop ( Energy  q) const
private

Return the value of $\Lambda$ and the number of flavours at the scale.

Parameters
qThe scale
Returns
The number of flavours at the scale and $\Lambda$.

◆ Init()

static void Herwig::ShowerAlphaQCD::Init ( )
static

The standard Init function used to initialize the interfaces.

Called exactly once for each class by the class description system before the main function starts or when this class is dynamically loaded.

◆ lambdaQCD()

Energy Herwig::ShowerAlphaQCD::lambdaQCD ( unsigned int  nf)
inline

Get the value of $\Lambda_{\rm QCd}$.

Parameters
nfnumber of flavours

Definition at line 96 of file ShowerAlphaQCD.h.

◆ operator=()

ShowerAlphaQCD& Herwig::ShowerAlphaQCD::operator= ( const ShowerAlphaQCD )
private

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

◆ persistentInput()

void Herwig::ShowerAlphaQCD::persistentInput ( PersistentIStream is,
int  version 
)

Function used to read in object persistently.

Parameters
isthe persistent input stream read from.
versionthe version number of the object when written.

◆ persistentOutput()

void Herwig::ShowerAlphaQCD::persistentOutput ( PersistentOStream os) const

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ value()

virtual double Herwig::ShowerAlphaQCD::value ( const Energy2  scale) const
virtual

Methods to return the coupling.

It returns the running coupling value evaluated at the input scale multiplied by the scale factor scaleFactor().

Parameters
scaleThe scale
Returns
The coupling

Implements Herwig::ShowerAlpha.


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