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Herwig  7.1.4

The a1ThreePionDecayer class is designed to implement the decay of the a_1 to three pions. More...

#include <a1ThreePionDecayer.h>

Inheritance diagram for Herwig::a1ThreePionDecayer:

Public Member Functions

 a1ThreePionDecayer ()
 Default constructor.
 
virtual int modeNumber (bool &cc, tcPDPtr parent, const tPDVector &children) const
 Which of the possible decays is required. More...
 
double me2 (const int ichan, const Particle &part, const ParticleVector &decay, MEOption meopt) const
 Return the matrix element squared for a given mode and phase-space channel. More...
 
virtual WidthCalculatorBasePtr threeBodyMEIntegrator (const DecayMode &dm) const
 Method to return an object to calculate the 3 body partial width. More...
 
virtual double threeBodyMatrixElement (const int imode, const Energy2 q2, const Energy2 s3, const Energy2 s2, const Energy2 s1, const Energy m1, const Energy m2, const Energy m3) const
 The matrix element to be integrated for the three-body decays as a function of the invariant masses of pairs of the outgoing particles. More...
 
virtual void dataBaseOutput (ofstream &os, bool header) const
 Output the setup information for the particle database. More...
 
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::DecayIntegrator
 DecayIntegrator ()
 Default constructor.
 
virtual bool accept (tcPDPtr parent, const tPDVector &children) const
 Check if this decayer can perfom the decay for a particular mode. More...
 
virtual ParticleVector decay (const Particle &parent, const tPDVector &children) const
 For a given decay mode and a given particle instance, perform the decay and return the decay products. More...
 
int imode () const
 The mode being used for this decay.
 
void addMode (DecayPhaseSpaceModePtr mode, double maxwgt, const vector< double > wgts) const
 Add a phase-space mode to the list. More...
 
DecayMEPtr ME () const
 The helicity amplitude matrix element for spin correlations.
 
virtual bool twoBodyMEcode (const DecayMode &, int &mecode, double &coupling) const
 Specify the $1\to2$ matrix element to be used in the running width calculation. More...
 
virtual InvEnergy threeBodydGammads (const int imode, const Energy2 q2, const Energy2 s, const Energy m1, const Energy m2, const Energy m3) const
 The differential three body decay rate with one integral performed. More...
 
void setPartialWidth (const DecayMode &dm, int imode)
 Set the code for the partial width. More...
 
int findMode (const DecayMode &dm)
 Finds the phase-space mode corresponding to a given decay mode. More...
 
ParticleVector generatePhotons (const Particle &p, ParticleVector children)
 Members for the generation of QED radiation in the decays. More...
 
bool canGeneratePhotons ()
 check if photons can be generated in the decay
 
virtual double oneLoopVirtualME (unsigned int imode, const Particle &part, const ParticleVector &products)
 The one-loop virtual correction. More...
 
bool hasOneLoopME ()
 Whether or not the one loop matrix element is implemented.
 
virtual InvEnergy2 realEmissionME (unsigned int imode, const Particle &part, ParticleVector &products, unsigned int iemitter, double ctheta, double stheta, const LorentzRotation &rot1, const LorentzRotation &rot2)
 The real emission matrix element. More...
 
bool hasRealEmissionME ()
 Whether or not the real emission matrix element is implemented.
 
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::HwDecayerBase
 HwDecayerBase ()
 The default constructor.
 
virtual bool accept (const DecayMode &dm) const
 Check if this decayer can perfom the decay specified by the given decay mode. More...
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p) const
 Perform a decay for a given DecayMode and a given Particle instance. 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...
 
bool initialize () const
 Access to the initialize variable.
 
bool databaseOutput () const
 Access the database output variable.
 
virtual POWHEGType hasPOWHEGCorrection ()
 Has a POWHEG style correction.
 
virtual bool hasMECorrection ()
 Has an old fashioned ME correction.
 
virtual void initializeMECorrection (RealEmissionProcessPtr, double &, double &)
 Initialize the ME correction.
 
virtual RealEmissionProcessPtr applyHardMatrixElementCorrection (RealEmissionProcessPtr)
 Apply the hard matrix element correction to a given hard process or decay.
 
virtual bool softMatrixElementVeto (ShowerProgenitorPtr initial, ShowerParticlePtr parent, Branching br)
 Apply the soft matrix element correction. More...
 
virtual RealEmissionProcessPtr generateHardest (RealEmissionProcessPtr)
 Apply the POWHEG style correction.
 
- Public Member Functions inherited from ThePEG::Decayer
Ptr< Amplitude >::pointer amplitude () const
 
virtual bool needsFullStep () const
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p, Step &step) const
 
virtual double brat (const DecayMode &dm, const ParticleData &pd, double oldbrat) const
 
virtual double brat (const DecayMode &dm, const Particle &p, double oldbrat) const
 
virtual ParticleVector getChildren (const DecayMode &dm, const Particle &parent) const
 
virtual void finalBoost (const Particle &parent, const ParticleVector &children) const
 
virtual void setScales (const Particle &parent, const ParticleVector &children) const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
virtual bool needsFullStep () const
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p, Step &step) const
 
virtual double brat (const DecayMode &dm, const ParticleData &pd, double oldbrat) const
 
virtual double brat (const DecayMode &dm, const Particle &p, double oldbrat) const
 
virtual ParticleVector getChildren (const DecayMode &dm, const Particle &parent) const
 
virtual void finalBoost (const Particle &parent, const ParticleVector &children) const
 
virtual void setScales (const Particle &parent, const ParticleVector &children) const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from HandlerBaseT< UseRandom >
double rnd () const
 
double rnd (double xu) const
 
double rnd (double xl, double xu) const
 
bool rndbool () const
 
bool rndbool (double p) const
 
bool rndbool (double p1, double p2) const
 
int rndsign (double p1, double p2, double p3) const
 
int rnd2 (double p0, double p1) const
 
int rnd3 (double p0, double p1, double p2) const
 
int rnd4 (double p0, double p1, double p2, double p3) const
 
long irnd (long xu=2) const
 
long irnd (long xl, long xu) const
 
const StandardModelBase & SM () const
 
tSMPtr standardModel () const
 
- 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 ()
 Standard Init function used to initialize the interfaces.
 
- Static Public Member Functions inherited from Herwig::DecayIntegrator
static void Init ()
 Standard Init function used to initialize the interfaces.
 
- Static Public Member Functions inherited from Herwig::HwDecayerBase
static void Init ()
 The standard Init function used to initialize the interfaces. More...
 
- Static Public Member Functions inherited from ThePEG::Decayer
static ParticleVector DecayParticle (tPPtr parent, Step &step, long maxtry=1000)
 
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::HandlerBase
static void Init ()
 
- 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 and EventGenerator to disk. More...
 
virtual void doinitrun ()
 Initialize this object to the begining of the run phase.
 
- Protected Member Functions inherited from Herwig::DecayIntegrator
ParticleVector generate (bool inter, bool cc, const unsigned int &imode, const Particle &inpart) const
 Generate the momenta for the decay. More...
 
void imode (int in)
 Set the mode being use for this decay.
 
void ME (DecayMEPtr in) const
 Set the helicity matrix element for the decay.
 
void resetIntermediate (tcPDPtr part, Energy mass, Energy width)
 Reset the properities of all intermediates. More...
 
unsigned int numberModes () const
 Number of decay modes.
 
tDecayPhaseSpaceModePtr mode (unsigned int)
 Pointer to a mode.
 
tcDecayPhaseSpaceModePtr mode (unsigned int) const
 Pointer to a mode.
 
bool generateIntermediates () const
 Get whether or not the intermediates are included.
 
void generateIntermediates (bool in)
 Set whether or not the intermediates are included.
 
Energy initializePhaseSpaceMode (unsigned int imode, bool init, bool onShell=false) const
 Initialize the phase-space mode. More...
 
void hasOneLoopME (bool in)
 Whether or not the one loop matrix element is implemented.
 
void hasRealEmissionME (bool in)
 Whether or not the real emission matrix element is implemented.
 
- Protected Member Functions inherited from Herwig::HwDecayerBase
virtual void dofinish ()
 Finalize this object. 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 IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
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

a1ThreePionDecayeroperator= (const a1ThreePionDecayer &)
 Private and non-existent assignment operator.
 
Complex sigmaBreitWigner (Energy2 q2) const
 Breit-wigner for the $\sigma$, this is $\frac1{D_\sigma(q^2)}$. More...
 
double a1FormFactor (Energy2 q2) const
 The $a_1$ form factor, $F_{a_1}(q^2)$. More...
 
Complex rhoBreitWigner (Energy2 q2, int ires) const
 Breit-Wigner for the $\rho$, this is $\frac1{D_{\rho_k}(q^2)}$. More...
 
Energy2 DParameter (int ires) const
 Normalisation factor for the $\rho$ propagator to ensure $D(0)=-1$. More...
 
double dhdq2Parameter (int ires) const
 The $\frac{dh}{dq^2}$ function in the rho propagator evaluated at $q^2=m^2$. More...
 
Energy2 hFunction (const Energy q) const
 The $h(q^2)$ function in the $\rho$ propagator. More...
 
Energy4 lambda (Energy2 a, Energy2 b, Energy2 c) const
 Momentum Function.
 

Private Attributes

vector< Energy > _rhomass
 Mass of the rho resonances.
 
vector< Energy > _rhowidth
 Width of the rho resonaces.
 
vector< Energy > _prho
 Momentum of the pions produced in the $\rho$ decay.
 
vector< Energy2 > _hm2
 The function $h(q^2)$ evaluated at $q^2=M^2_{\rho_k}$.
 
vector< Energy2 > _rhoD
 The normalization factor for the $\rho_k$ propagator factor.
 
vector< double > _dhdq2m2
 The $\frac{dh}{dq^2}$ function in the rho propagator evaluated at $q^2=m^2$ for the different $\rho$ multiplets.
 
Energy _sigmamass
 The mass of the $\sigma$ meson.
 
Energy _sigmawidth
 The width of the $\sigma$ meson.
 
Energy _psigma
 The momenta of the pions produced in the $\sigma$ meson decay.
 
Energy _mpi
 The mass of the pion, $m_\pi$.
 
Energy2 _mpi2
 The mass of the pion, $m^2_\pi$.
 
Energy2 _lambda2
 The $\Lambda^2$ parameter for the $a_1$ form factor.
 
Energy2 _a1mass2
 The mass squared of the $a_1$ meson, $m_{a_1}^2$.
 
Complex _zsigma
 The $z$ coupling for the $\sigma$ resonance.
 
double _zmag
 The magnitude of the $z$ $\sigma$ coupling.
 
double _zphase
 The phase of the $z$ $\sigma$ coupling.
 
vector< Complex_rhocoupling
 $g_{\rho_k}$ is the coupling of the $k$ th $\rho$ multiplet.
 
vector< double > _rhomag
 Magnitude of the rho coupling.
 
vector< double > _rhophase
 Phase of the rho coupling.
 
double _coupling
 The overall coupling for the decay.
 
bool _localparameters
 use local values of the mass parameters
 
vector< double > _zerowgts
 Weights for the channels for the zero charged pion channel.
 
vector< double > _onewgts
 Weights for the channels for the one charged pion channel.
 
vector< double > _twowgts
 Weights for the channels for the two charged pion channel.
 
vector< double > _threewgts
 Weights for the channels for the three charged pion channel.
 
double _zeromax
 Maximum weight for the zero charged pion channel.
 
double _onemax
 Maximum weight for the one charged pion channel.
 
double _twomax
 Maximum weight for the two charged pion channel.
 
double _threemax
 Maximum weight for the three charged pion channel.
 
RhoDMatrix _rho
 Spin density matrix.
 
vector< Helicity::LorentzPolarizationVector_vectors
 Polarization vectors.
 

Static Private Attributes

static ClassDescription< a1ThreePionDecayerinita1ThreePionDecayer
 Describe a concrete class with persistent data.
 

Additional Inherited Members

- Public Types inherited from Herwig::DecayIntegrator
enum  MEOption { Initialize, Calculate, Terminate }
 Enum for the matrix element option.
 
- Public Types inherited from Herwig::HwDecayerBase
enum  POWHEGType { No, ISR, FSR, Both }
 Virtual members to be overridden by inheriting classes which implement hard corrections. More...
 
- 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

The a1ThreePionDecayer class is designed to implement the decay of the a_1 to three pions.

The model used is one based on the Novosibirsk four pion current used in TAUOLA.

  • The matrix element for the decay $a_1^0\to\pi^0\pi^0\pi^0$ is

\[J^\mu =\frac{F_{a_1}(q^2)g}{qM^2_{\rho_0}}\epsilon_\mu\left[ q^2z \sum_i p^\mu_i \frac1{D_\sigma(s_i)}\right]\]

  • The matrix element for the decay $a_1^+\to\pi^0\pi^0\pi^+$ is

\[J^\mu =\frac{F_{a_1}(q^2)g}{qM^2_{\rho_0}}\epsilon_\mu\left[ q^2z\frac1{D_\sigma(s_3)} p_3^\mu +\sum_k g_{\rho_k}\left\{ \frac1{D_{\rho_k}(s_1)}\left(p_0\cdot p_3p_2^\mu-p_0\cdot p_2p_3^\mu\right) +\frac1{D_{\rho_k}(s_2)}\left(p_0\cdot p_3p_1^\mu-p_0\cdot p_1p_3^\mu\right) \right\} \right]\]

  • The matrix element for the decay $a_10\to\pi^+\pi^-\pi^0$ is

\[J^\mu =\frac{F_{a_1}(q^2)g}{qM^2_{\rho_0}}\left[ q^2z\frac1{D_\sigma(s_3)}p_3^\mu +\sum_k g_{\rho_k}\left\{ \frac1{D_{\rho_k}(s_1)}\left(p_0\cdot p_3p_2^\mu-p_0\cdot p_2p_3^\mu\right) +\frac1{D_{\rho_k}(s_2)}\left(p_0\cdot p_3p_1^\mu-p_0\cdot p_1p_3^\mu\right)\right\} \right]\]

  • The current for the decay $a_1^+\to\pi^+\pi^+\pi^-$ is

\[J^\mu = \frac{F_{a_1}(q^2)g}{qM^2_{\rho_0}}\left[ q^2z\left(\frac1{D_\sigma(s_1)}p_1^\mu+\frac1{D_\sigma(s_2)}p_2^\mu\right) -\sum_k g_{\rho_k}\left\{ \frac1{D_{\rho_k}(s_1)}\left(p_0\cdot p_3p_2^\mu-p_0\cdot p_2p_3^\mu\right) +\frac1{D_{\rho_k}(s_2)}\left(p_0\cdot p_3p_1^\mu-p_0\cdot p_1p_3^\mu\right)\right\} \right]\]

  • The denominator factor is

    \[D_\sigma(q^2) = q^2-M^2+iM\Gamma\frac{g_\sigma(q^2)}{g_\sigma(M^2)}\]

    where $g(s) = \left(1-4\frac{m_{\pi}^2}{s}\right)$ for the $\sigma$ meson, and

    \[D_{\rho_k}(q^2) = q^2-M^2_{\rho_k}-M_{\rho_k}\Gamma_{\rho_k}dm(q^2) +iM_{\rho_k}\Gamma_{\rho_k}\frac{g_{\rho_k}(q^2)}{g_{\rho_k}(M^2)} \]

    for the $\rho$.

The propagator factors are normalized such that $D(0)=-1$.

Here

\[dm(q^2) = \frac1{g_{\rho_k}(M^2_{\rho_k}}\left(h_{\rho_k}(q^2)-h_{\rho_k}(M^2_{\rho_k} -\left.(q^2-M^2_{\rho_k})\frac{dh_{\rho_k}(q^2)}{dq^2}\right|_{q^2=M^2_{\rho_k}} \right)\]

where

\[h_{\rho_k}(q^2) = \left\{ \begin{array}{cc} \frac{\sqrt{1-\frac{4m_\pi^2}{q^2}}\ln\left(\frac{1+\sqrt{1-\frac{4m_\pi^2}{q^2}}}{1-\sqrt{1-\frac{4m_\pi^2}{q^2}}}\right)(q^2-4m_\pi^2)}\pi & {\rm for\ } q^2>4m_\pi^2 \\ -8\frac{m_\pi^2}{\pi} & {\rm for\ } q^2=0\,{\rm GeV^2} \\ 0 & {\rm otherwise} \end{array}\right.\]

The $a_1$ form factor for the off-shell $a_1$ is given by

\[F_{a_1}(q^2) = \frac{\left(1+m^2_{a_1}/\Lambda^2\right)} {\left(1+ q^2/\Lambda^2\right)}.\]

The masses and couplings are

  • $z$ is the relative coupling of the $\sigma$.
  • $m_\pi$ is the mass of the pion.
  • $g_{\rho_k}$ is the coupling of the $k$th $\rho$ multiplet.
  • $M_{\rho_k}$ the mass of the $k$th $\rho$ resonance.
  • $\Gamma_{\rho_k}$ the width of the $k$th $\rho$ resonance.
  • $M_\sigma$ the mass of the $\sigma$ meson.
  • $\Gamma_\sigma$ the width of the $\sigma$ meson.
  • $m_{a_1}$ the mass of the $a_1$ meson.
  • $\Lambda^2$ the mass parameter for the $a_1$ form factor.
    See also
    FourPionNovosibirskCurrent
    DecayIntegrator

Definition at line 102 of file a1ThreePionDecayer.h.

Member Function Documentation

◆ a1FormFactor()

double Herwig::a1ThreePionDecayer::a1FormFactor ( Energy2  q2) const
inlineprivate

The $a_1$ form factor, $F_{a_1}(q^2)$.

Parameters
q2The scale, $q^2$.
Returns
The form factor.

Definition at line 254 of file a1ThreePionDecayer.h.

◆ clone()

virtual IBPtr Herwig::a1ThreePionDecayer::clone ( ) const
inlineprotectedvirtual

Make a simple clone of this object.

Returns
a pointer to the new object.

Implements ThePEG::InterfacedBase.

Definition at line 194 of file a1ThreePionDecayer.h.

◆ dataBaseOutput()

virtual void Herwig::a1ThreePionDecayer::dataBaseOutput ( ofstream &  os,
bool  header 
) const
virtual

Output the setup information for the particle database.

Parameters
osThe stream to output the information to
headerWhether or not to output the information for MySQL

Reimplemented from Herwig::DecayIntegrator.

◆ dhdq2Parameter()

double Herwig::a1ThreePionDecayer::dhdq2Parameter ( int  ires) const
inlineprivate

The $\frac{dh}{dq^2}$ function in the rho propagator evaluated at $q^2=m^2$.

Parameters
iresThe $\rho$ resonance for the function
Returns
$\frac{dh}{dq^2}$ evaluated at $q^2=m^2$.

Definition at line 301 of file a1ThreePionDecayer.h.

References ThePEG::Constants::pi, sqr(), and sqrt().

◆ doinit()

virtual void Herwig::a1ThreePionDecayer::doinit ( )
protectedvirtual

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

Exceptions
InitExceptionif object could not be initialized properly.

Reimplemented from ThePEG::InterfacedBase.

◆ DParameter()

Energy2 Herwig::a1ThreePionDecayer::DParameter ( int  ires) const
inlineprivate

Normalisation factor for the $\rho$ propagator to ensure $D(0)=-1$.

Parameters
iresThe $\rho$ multiplet.
Returns
The normalisation factor.

Definition at line 290 of file a1ThreePionDecayer.h.

References sqr(), and ZERO.

◆ fullclone()

virtual IBPtr Herwig::a1ThreePionDecayer::fullclone ( ) const
inlineprotectedvirtual

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 200 of file a1ThreePionDecayer.h.

◆ hFunction()

Energy2 Herwig::a1ThreePionDecayer::hFunction ( const Energy  q) const
inlineprivate

The $h(q^2)$ function in the $\rho$ propagator.

Parameters
qThe scale, $q$.
Returns
The function $h(q^2)$.

Definition at line 313 of file a1ThreePionDecayer.h.

References sqr(), sqrt(), and ZERO.

◆ me2()

double Herwig::a1ThreePionDecayer::me2 ( const int  ichan,
const Particle part,
const ParticleVector decay,
MEOption  meopt 
) const
virtual

Return the matrix element squared for a given mode and phase-space channel.

Parameters
ichanThe channel we are calculating the matrix element for.
partThe decaying Particle.
decayThe particles produced in the decay.
meoptOption for the calculation of the matrix element
Returns
The matrix element squared for the phase-space configuration.

Implements Herwig::DecayIntegrator.

◆ modeNumber()

virtual int Herwig::a1ThreePionDecayer::modeNumber ( bool &  cc,
tcPDPtr  parent,
const tPDVector children 
) const
virtual

Which of the possible decays is required.

Parameters
ccIs this mode the charge conjugate
parentThe decaying particle
childrenThe decay products

Implements Herwig::DecayIntegrator.

◆ persistentInput()

void Herwig::a1ThreePionDecayer::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::a1ThreePionDecayer::persistentOutput ( PersistentOStream os) const

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ rhoBreitWigner()

Complex Herwig::a1ThreePionDecayer::rhoBreitWigner ( Energy2  q2,
int  ires 
) const
inlineprivate

Breit-Wigner for the $\rho$, this is $\frac1{D_{\rho_k}(q^2)}$.

Parameters
q2The scale, $q^2$.
iresThe $\rho$ multiplet.
Returns
The Breit-Wigner

Definition at line 264 of file a1ThreePionDecayer.h.

References Herwig::Kinematics::pstarTwoBodyDecay(), and sqrt().

◆ sigmaBreitWigner()

Complex Herwig::a1ThreePionDecayer::sigmaBreitWigner ( Energy2  q2) const
inlineprivate

Breit-wigner for the $\sigma$, this is $\frac1{D_\sigma(q^2)}$.

Parameters
q2The scale, $q^2$.
Returns
The Breit-Wigner

Definition at line 239 of file a1ThreePionDecayer.h.

References Herwig::Kinematics::pstarTwoBodyDecay(), and sqrt().

◆ threeBodyMatrixElement()

virtual double Herwig::a1ThreePionDecayer::threeBodyMatrixElement ( const int  imode,
const Energy2  q2,
const Energy2  s3,
const Energy2  s2,
const Energy2  s1,
const Energy  m1,
const Energy  m2,
const Energy  m3 
) const
virtual

The matrix element to be integrated for the three-body decays as a function of the invariant masses of pairs of the outgoing particles.

Parameters
imodeThe mode for which the matrix element is needed.
q2The scale, i.e. the mass squared of the decaying particle.
s3The invariant mass squared of particles 1 and 2, $s_3=m^2_{12}$.
s2The invariant mass squared of particles 1 and 3, $s_2=m^2_{13}$.
s1The invariant mass squared of particles 2 and 3, $s_1=m^2_{23}$.
m1The mass of the first outgoing particle.
m2The mass of the second outgoing particle.
m3The mass of the third outgoing particle.
Returns
The matrix element

Reimplemented from Herwig::DecayIntegrator.

◆ threeBodyMEIntegrator()

virtual WidthCalculatorBasePtr Herwig::a1ThreePionDecayer::threeBodyMEIntegrator ( const DecayMode dm) const
virtual

Method to return an object to calculate the 3 body partial width.

Parameters
dmThe DecayMode
Returns
A pointer to a WidthCalculatorBase object capable of calculating the width

Reimplemented from Herwig::DecayIntegrator.


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