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Herwig++  2.7.0
Herwig::QTildeSudakov Class Reference

The QTildeSudakov class implements the Sudakov form factor for evolution in $\tilde{q}^2$ using the veto algorithm. More...

#include <QTildeSudakov.h>

Inheritance diagram for Herwig::QTildeSudakov:

List of all members.

Public Member Functions

 QTildeSudakov ()
 The default constructor.
virtual Energy calculateScale (double z, Energy pt, IdList ids, unsigned int iopt)
 Method to return the evolution scale given the transverse momentum, $p_T$ and $z$.
virtual ShoKinPtr createFinalStateBranching (Energy scale, double z, double phi, Energy pt)
 Method to create the ShowerKinematics object for a final-state branching.
virtual ShoKinPtr createInitialStateBranching (Energy scale, double z, double phi, Energy pt)
 Method to create the ShowerKinematics object for an initial-state branching.
virtual ShoKinPtr createDecayBranching (Energy scale, double z, double phi, Energy pt)
 Method to create the ShowerKinematics object for a decay branching.
virtual ShoKinPtr generateNextTimeBranching (const Energy startingScale, const IdList &ids, const bool cc, double enhance)
 Members to generate the scale of the next branching.
virtual ShoKinPtr generateNextDecayBranching (const Energy startingScale, const Energy stoppingScale, const Energy minmass, const IdList &ids, const bool cc, double enhance)
 Return the scale of the next space-like decay branching.
virtual ShoKinPtr generateNextSpaceBranching (const Energy startingScale, const IdList &ids, double x, const bool cc, double enhance, tcBeamPtr beam)
 Return the scale of the next space-like branching.
Functions used by the persistent I/O system.
void persistentOutput (PersistentOStream &os) const
 Function used to write out object persistently.
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently.

Static Public Member Functions

static void Init ()
 The standard Init function used to initialize the interfaces.

Protected Member Functions

void initialize (const IdList &ids, Energy2 &tmin, const bool cc)
 Initialize the values of the cut-offs and scales.
bool PSVeto (const Energy2 t)
 Phase Space veto member to implement the $\Theta$ function as a veto so that the emission is within the allowed phase space.
bool computeTimeLikeLimits (Energy2 &scale)
 Compute the limits on $z$ for time-like branching.
bool computeSpaceLikeLimits (Energy2 &scale, double x)
 Compute the limits on $z$ for space-like branching.
bool guessTimeLike (Energy2 &t, Energy2 tmin, double enhance)
 Methods to provide the next value of the scale before the vetos are applied.
bool guessDecay (Energy2 &t, Energy2 tmax, Energy minmass, double enhance)
 Value of the energy fraction and scale for time-like branching.
bool guessSpaceLike (Energy2 &t, Energy2 tmin, const double x, double enhance)
 Value of the energy fraction and scale for space-like branching.
Clone Methods.
virtual IBPtr clone () const
 Make a simple clone of this object.
virtual IBPtr fullclone () const
 Make a clone of this object, possibly modifying the cloned object to make it sane.

Private Member Functions

QTildeSudakovoperator= (const QTildeSudakov &)
 The assignment operator is private and must never be called.

Private Attributes

Energy q_
 The evolution scale, $\tilde{q}$.
IdList ids_
 The Ids of the particles in the current branching.
vector< Energy > masses_
 The masses of the particles in the current branching.
vector< Energy2 > masssquared_
 The mass squared of the particles in the current branching.

Detailed Description

The QTildeSudakov class implements the Sudakov form factor for evolution in $\tilde{q}^2$ using the veto algorithm.

See also:
The interfaces defined for QTildeSudakov.

Definition at line 29 of file QTildeSudakov.h.


Member Function Documentation

virtual IBPtr Herwig::QTildeSudakov::clone ( ) const [inline, protected, virtual]

Make a simple clone of this object.

Returns:
a pointer to the new object.

Implements ThePEG::InterfacedBase.

Definition at line 215 of file QTildeSudakov.h.

bool Herwig::QTildeSudakov::computeSpaceLikeLimits ( Energy2 &  scale,
double  x 
) [protected]

Compute the limits on $z$ for space-like branching.

Parameters:
scaleThe scale of the particle
xThe energy fraction of the parton
Returns:
True if lower limit less than upper, otherwise false
bool Herwig::QTildeSudakov::computeTimeLikeLimits ( Energy2 &  scale) [protected]

Compute the limits on $z$ for time-like branching.

Parameters:
scaleThe scale of the particle
Returns:
True if lower limit less than upper, otherwise false
virtual IBPtr Herwig::QTildeSudakov::fullclone ( ) const [inline, protected, virtual]

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.

Definition at line 221 of file QTildeSudakov.h.

virtual ShoKinPtr Herwig::QTildeSudakov::generateNextDecayBranching ( const Energy  startingScale,
const Energy  stoppingScale,
const Energy  minmass,
const IdList ids,
const bool  cc,
double  enhance 
) [virtual]

Return the scale of the next space-like decay branching.

If there is no branching then it returns ZERO.

Parameters:
startingScalestarting scale for the evolution
stoppingScalestopping scale for the evolution
minmassThe minimum mass allowed for the spake-like particle.
idsThe PDG codes of the particles in the splitting
ccWhether this is the charge conjugate of the branching defined.
enhanceThe radiation enhancement factor

Implements Herwig::SudakovFormFactor.

virtual ShoKinPtr Herwig::QTildeSudakov::generateNextSpaceBranching ( const Energy  startingScale,
const IdList ids,
double  x,
const bool  cc,
double  enhance,
tcBeamPtr  beam 
) [virtual]

Return the scale of the next space-like branching.

If there is no branching then it returns ZERO.

Parameters:
startingScalestarting scale for the evolution
idsThe PDG codes of the particles in the splitting
xThe fraction of the beam momentum
ccWhether this is the charge conjugate of the branching defined.
enhanceThe radiation enhancement factor
beamThe beam particle

Implements Herwig::SudakovFormFactor.

virtual ShoKinPtr Herwig::QTildeSudakov::generateNextTimeBranching ( const Energy  startingScale,
const IdList ids,
const bool  cc,
double  enhance 
) [virtual]

Members to generate the scale of the next branching.

Return the scale of the next time-like branching. If there is no branching then it returns ZERO.

Parameters:
startingScalestarting scale for the evolution
idsThe PDG codes of the particles in the splitting
ccWhether this is the charge conjugate of the branching defined.
enhanceThe radiation enhancement factor

Implements Herwig::SudakovFormFactor.

bool Herwig::QTildeSudakov::guessDecay ( Energy2 &  t,
Energy2  tmax,
Energy  minmass,
double  enhance 
) [protected]

Value of the energy fraction and scale for time-like branching.

Parameters:
tThe scale
tmaxThe maximum scale
minmassThe minimum mass of the particle after the branching
enhanceThe radiation enhancement factor
bool Herwig::QTildeSudakov::guessSpaceLike ( Energy2 &  t,
Energy2  tmin,
const double  x,
double  enhance 
) [protected]

Value of the energy fraction and scale for space-like branching.

Parameters:
tThe scale
tminThe minimum scale
xFraction of the beam momentum.
enhanceThe radiation enhancement factor
bool Herwig::QTildeSudakov::guessTimeLike ( Energy2 &  t,
Energy2  tmin,
double  enhance 
) [protected]

Methods to provide the next value of the scale before the vetos are applied.

Value of the energy fraction and scale for time-like branching

Parameters:
tThe scale
tminThe minimum scale
enhanceThe radiation enhancement factor
Returns:
False if scale less than minimum, true otherwise
static void Herwig::QTildeSudakov::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.

Reimplemented from Herwig::SudakovFormFactor.

void Herwig::QTildeSudakov::initialize ( const IdList ids,
Energy2 &  tmin,
const bool  cc 
) [protected]

Initialize the values of the cut-offs and scales.

Parameters:
tminThe minimum scale
idsThe ids of the partics in the branching
ccWhether this is the charge conjugate of the branching
QTildeSudakov& Herwig::QTildeSudakov::operator= ( const QTildeSudakov ) [private]

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

Function used to read in object persistently.

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

Reimplemented from Herwig::SudakovFormFactor.

Function used to write out object persistently.

Parameters:
osthe persistent output stream written to.

Reimplemented from Herwig::SudakovFormFactor.

bool Herwig::QTildeSudakov::PSVeto ( const Energy2  t) [protected]

Phase Space veto member to implement the $\Theta$ function as a veto so that the emission is within the allowed phase space.

Parameters:
tThe scale
Returns:
true if vetoed

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