PYTHIA  8.303
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HMETau2FourPions Class Reference

Helicity matrix element for a tau decay into four pions. More...

#include <HelicityMatrixElements.h>

Inheritance diagram for HMETau2FourPions:
HMETauDecay HelicityMatrixElement

Public Member Functions

void initConstants ()
 Initialize constants for the helicity matrix element. More...
 
void initHadronicCurrent (vector< HelicityParticle > &p)
 Initialize the hadronic current for the helicity matrix element. More...
 
- Public Member Functions inherited from HMETauDecay
virtual void initWaves (vector< HelicityParticle > &)
 Initialize wave functions for the helicity matrix element. More...
 
virtual complex calculateME (vector< int >)
 Return element for the helicity matrix element.
 
virtual double decayWeightMax (vector< HelicityParticle > &)
 Return the maximum decay weight for the helicity matrix element. More...
 
- Public Member Functions inherited from HelicityMatrixElement
 HelicityMatrixElement ()
 Constructor and destructor.
 
virtual void initPointers (ParticleData *, CoupSM *, Settings *=0)
 Initialize the physics matrices and pointers. More...
 
virtual HelicityMatrixElementinitChannel (vector< HelicityParticle > &)
 Initialize the channel. More...
 
virtual double decayWeight (vector< HelicityParticle > &)
 Calculate the matrix element weight for a decay. More...
 
virtual void calculateD (vector< HelicityParticle > &)
 Calculate the decay matrix for a particle. More...
 
virtual void calculateRho (unsigned int, vector< HelicityParticle > &)
 Calculate the density matrix for a particle. More...
 
void setFermionLine (int, HelicityParticle &, HelicityParticle &)
 Set a fermion line. More...
 
virtual complex breitWigner (double s, double M, double G)
 Calculate Breit-Wigner's with running widths and fixed. More...
 
virtual complex sBreitWigner (double m0, double m1, double s, double M, double G)
 Return an s-wave BreitWigner.
 
virtual complex pBreitWigner (double m0, double m1, double s, double M, double G)
 Return a p-wave BreitWigner.
 
virtual complex dBreitWigner (double m0, double m1, double s, double M, double G)
 Return a d-wave BreitWigner.
 

Additional Inherited Members

- Protected Member Functions inherited from HMETauDecay
virtual void calculateResonanceWeights (vector< double > &, vector< double > &, vector< complex > &)
 Calculate complex resonance weights given a phase and amplitude vector.
 
- Protected Attributes inherited from HelicityMatrixElement
double DECAYWEIGHTMAX
 Maximum decay weight. WARNING: hardcoded constant.
 
vector< GammaMatrixgamma
 Physics matrices.
 
vector< int > pMap
 Particle map vector.
 
vector< int > pID
 Particle ID vector.
 
vector< double > pM
 Particle mass vector.
 
vector< vector< Wave4 > > u
 Wave functions.
 
ParticleDataparticleDataPtr
 Pointer to particle data.
 
CoupSMcoupSMPtr
 Pointer to Standard Model constants.
 
SettingssettingsPtr
 Pointer to Settings.
 

Detailed Description

Helicity matrix element for a tau decay into four pions.

Member Function Documentation

void initConstants ( )
virtual

Initialize constants for the helicity matrix element.

Tau decay matrix element for tau decay into pions using the Novosibirsk model of Comp. Phys. Com. 174 (2006) 818-835. G(i,s): G-factor for index 1, 2, or 3 tX(q,q1,q2,q3,q4): combined resonance current a1D(s): a1 Breit-Wigner denominator rhoD(s): rho Breit-Wigner denominator sigD(s): sigma Breit-Wigner denominator omeD(s): omega Breit-Wigner denominator a1FormFactor(s): form factor for the a1 resonance rhoFormFactor1(2)(s): form factor for the rho resonance omeFormFactor(s): form factor for the omega resonance sigM: on-shell mass of the sigma resonance sigG: width of the sigma resonance sigA: amplitude of the sigma resonance sigP: phase of the sigma resonance sigW: weight of the sigma resonance (from amplitude and weight) omeX: mass, width, amplitude, phase, and weight of the omega resonance a1X: mass and width of the a1 resonance rhoX: mass and width of the rho resonance picM: charge pion mass pinM: neutral pion mass lambda2: a1 form factor cut-off

Reimplemented from HelicityMatrixElement.

void initHadronicCurrent ( vector< HelicityParticle > &  p)
virtual

Initialize the hadronic current for the helicity matrix element.

Create pion momenta.

Calculate the four pion system energy.

Create the hadronic current for the 3 neutral pion channel.

Create the hadronic current for the 3 charged pion channel.

Reimplemented from HMETauDecay.


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