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Herwig  7.2.1
Herwig::YFSFormFactors Class Reference

The YFSFormFactors class is a pure static class which implements the various YFS form factors we need for the decays. More...

#include <YFSFormFactors.h>

Static Public Member Functions

static double nbarIF (double beta, double ombeta, double charge, Energy Emax, Energy Emin, bool massterms=false)
 Crude multiplicity for the initial-final dipole. More...
 
static Energy photonMass ()
 Access to the photon mass.
 
static double exponentialYFSIF (double beta0, double ombeta0, double beta1, double ombeta1, Energy en0, Energy en1, Energy m0, Energy m1, Energy2 t, double charge, Energy emin)
 Exponentials of the YFS form factors. More...
 
static double exponentialYFSFF (double beta1, double ombeta1, double beta2, double ombeta2, Energy en1, Energy en2, Energy m1, Energy m2, Energy2 s, double charge, Energy emin)
 The exponential of the YFS form factor for the final-final dipole The $2\alpha\tilde{B}$ function for the final-final dipole. More...
 
static double YFSIF (double beta0, double ombeta0, double beta1, double ombeta1, Energy en0, Energy en1, Energy m0, Energy m1, Energy2 t, double charge, Energy emin)
 The YFS form factors for the initial-final and final-final dipoles. More...
 
static double YFSFF (double beta1, double ombeta1, double beta2, double ombeta2, Energy en1, Energy en2, Energy m1, Energy m2, Energy2 s, double charge, Energy emin)
 The YFS form factor for the final-final dipole The $2\alpha\tilde{B}$ function for the final-final dipole. More...
 
static double nbarFF (double beta1, double ombeta1, double beta2, double ombeta2, double charge, Energy Emax, Energy Emin, bool massterms=false)
 Crude average multiplicities for initial-final and final-final dipoles. More...
 
static double ReBIF (Energy m0, Energy m1, Energy2 t, double charge, bool includegamma=true, Energy mgamma=_mgamma)
 The virtual piece for the initial-final and final-final dipoles. More...
 
static double ReBFF (Energy m1, Energy m2, Energy2 s, double charge, bool includegamma=true, Energy mgamma=_mgamma)
 The $2\alpha\mathcal{R}B$ function for the final-final dipole. More...
 
static double BtildeIF (double beta0, double ombeta0, double beta1, double ombeta1, Energy en0, Energy en1, Energy m0, Energy m1, Energy2 t, double charge, Energy emin, bool includegamma=true, Energy mgamma=_mgamma)
 The real emission terms for initial-final and final-final dipoles. More...
 
static double BtildeFF (double beta1, double ombeta1, double beta2, double ombeta2, Energy en1, Energy en2, Energy m1, Energy m2, Energy2 s, double charge, Energy emin, bool includegamma=true, Energy mgamma=_mgamma)
 The $2\alpha\tilde{B}$ function for the final-final dipole. More...
 

Static Public Attributes

static const double _alpha
 The value of $\alpha$ at $q^2=0$.
 

Static Private Member Functions

static InvEnergy2 A4FFFull (Energy inen1, Energy inen2, double beta1, double beta2, Energy inm1, Energy inm2, Energy2 s)
 Various special cases of the $A_4$ functions of hep-ph/0302065 for the initial-final dipole. More...
 
static InvEnergy2 A4IF (double beta0, double ombeta0, double beta1, double ombeta1, Energy en0, Energy en1, Energy m0, Energy m1, Energy2 t)
 The $A_4$ function of hep-ph0302065 using the special cases where necessary for numerical stability. More...
 
static double A4single (double beta, double ombeta)
 The $A_4$ function of hep-ph/0302065 for a single particle, without the $1/p^2$ pre-factor.
 
static InvEnergy2 A4IFRestZero (Energy m0, Energy m1)
 The $A_4$ function of hep-ph/0302065 for the initial-final dipole with $t=0$ in the rest frame. More...
 
static InvEnergy2 A4IFZero (double beta0, double beta1, double ombeta1, Energy en0, Energy en1, Energy m0, Energy m1)
 The $A_4$ function for the initial-final dipole with $t=0$. More...
 
static InvEnergy2 A4IFRest (Energy m0, Energy m1, double beta1, double ombeta1, Energy E1)
 The $A_4$ function for the initial-final dipole in the rest frame of the decaying particle. More...
 
static InvEnergy2 A4IFFull (Velocity beta0, Velocity beta1, Energy en0, Energy en1, Energy m0, Energy m1, Energy2 t)
 The $A_4$ function for the full initial-final dipole. More...
 
template<typename T >
static double Zij (T eta, T yi, T yj)
 Functions from hep-ph/9606429 for the calculation of the $A_4$ functions. More...
 
template<typename T >
static double Xijkl (T eta, T yi, T yj, T yk, T yl)
 The function $X^{ij}_{kl}(\eta)$ from hep-ph/9606429 for the evaluation of the $A_4$ function. More...
 

Static Private Attributes

static const Energy _mgamma
 The default value of the photon mass.
 
static const Energy2 _tcut
 The cut-off on the value of $t$ for the switch to the $t=0$ result.
 
static const Energy _ecut
 The cut-off on the energy of a particle for it to be considered in its rest frame.
 

Detailed Description

The YFSFormFactors class is a pure static class which implements the various YFS form factors we need for the decays.

Definition at line 26 of file YFSFormFactors.h.

Member Function Documentation

◆ A4FFFull()

static InvEnergy2 Herwig::YFSFormFactors::A4FFFull ( Energy  inen1,
Energy  inen2,
double  beta1,
double  beta2,
Energy  inm1,
Energy  inm2,
Energy2  s 
)
staticprivate

Various special cases of the $A_4$ functions of hep-ph/0302065 for the initial-final dipole.

The $A_4$ function for the full final-final dipole

Parameters
inen1The energy of the first particle
inen2The energy of the second particle
beta1Velocity of the first particle, $\beta_1$
beta2Velocity of the second particle, $\beta_2$.
inm1The mass of the first particle
inm2The mass of the second particle
sThe invariant mass of the charged particles

◆ A4IF()

static InvEnergy2 Herwig::YFSFormFactors::A4IF ( double  beta0,
double  ombeta0,
double  beta1,
double  ombeta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1,
Energy2  t 
)
staticprivate

The $A_4$ function of hep-ph0302065 using the special cases where necessary for numerical stability.

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
ombeta0One minus the velocity of the incoming particle, $1-\beta_0$
ombeta1One minus the velocity of the outgoing particle, $1-\beta_1$
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles

◆ A4IFFull()

static InvEnergy2 Herwig::YFSFormFactors::A4IFFull ( Velocity  beta0,
Velocity  beta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1,
Energy2  t 
)
staticprivate

The $A_4$ function for the full initial-final dipole.

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles

◆ A4IFRest()

static InvEnergy2 Herwig::YFSFormFactors::A4IFRest ( Energy  m0,
Energy  m1,
double  beta1,
double  ombeta1,
Energy  E1 
)
staticprivate

The $A_4$ function for the initial-final dipole in the rest frame of the decaying particle.

Parameters
m0The mass of the incoming particle
m1The mass of the outgoing particle
beta1The velocity of the decay product
ombeta1$1-\beta$ for the decay product
E1The energy of the outgoing particle

◆ A4IFRestZero()

static InvEnergy2 Herwig::YFSFormFactors::A4IFRestZero ( Energy  m0,
Energy  m1 
)
inlinestaticprivate

The $A_4$ function of hep-ph/0302065 for the initial-final dipole with $t=0$ in the rest frame.

Parameters
m0The mass of the incoming particle
m1The mass of the outgoing particle

Definition at line 348 of file YFSFormFactors.h.

References Herwig::Math::ReLi2(), and sqr().

◆ A4IFZero()

static InvEnergy2 Herwig::YFSFormFactors::A4IFZero ( double  beta0,
double  beta1,
double  ombeta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1 
)
staticprivate

The $A_4$ function for the initial-final dipole with $t=0$.

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
ombeta1$1-\beta_1$ for the outgoing charged particle.
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle

◆ BtildeFF()

static double Herwig::YFSFormFactors::BtildeFF ( double  beta1,
double  ombeta1,
double  beta2,
double  ombeta2,
Energy  en1,
Energy  en2,
Energy  m1,
Energy  m2,
Energy2  s,
double  charge,
Energy  emin,
bool  includegamma = true,
Energy  mgamma = _mgamma 
)
static

The $2\alpha\tilde{B}$ function for the final-final dipole.

Parameters
beta1Velocity of the first charged particle, $\beta_1$
beta2Velocity of the second charged particle, $\beta_2$.
ombeta1One minus the velocity of the first particle, $1-\beta_1$
ombeta2One minus the velocity of the second particle, $1-\beta_2$
en1The energy of the first particle
en2The energy of the second particle
m1The mass of the first particle
m2The mass of the second particle
sThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy
includegammaInclude the photon mass terms
mgammaThe photon mass,

◆ BtildeIF()

static double Herwig::YFSFormFactors::BtildeIF ( double  beta0,
double  ombeta0,
double  beta1,
double  ombeta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1,
Energy2  t,
double  charge,
Energy  emin,
bool  includegamma = true,
Energy  mgamma = _mgamma 
)
static

The real emission terms for initial-final and final-final dipoles.

The $2\alpha\tilde{B}$ function for the initial-final dipole

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
ombeta0One minus the velocity of the incoming particle, $1-\beta_0$
ombeta1One minus the velocity of the outgoing particle, $1-\beta_1$
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy
includegammaInclude the photon mass terms
mgammaThe photon mass,

◆ exponentialYFSFF()

static double Herwig::YFSFormFactors::exponentialYFSFF ( double  beta1,
double  ombeta1,
double  beta2,
double  ombeta2,
Energy  en1,
Energy  en2,
Energy  m1,
Energy  m2,
Energy2  s,
double  charge,
Energy  emin 
)
inlinestatic

The exponential of the YFS form factor for the final-final dipole The $2\alpha\tilde{B}$ function for the final-final dipole.

Parameters
beta1Velocity of the first charged particle, $\beta_1$
beta2Velocity of the second charged particle, $\beta_2$.
ombeta1One minus the velocity of the first particle, $1-\beta_1$
ombeta2One minus the velocity of the second particle, $1-\beta_2$
en1The energy of the first particle
en2The energy of the second particle
m1The mass of the first particle
m2The mass of the second particle
sThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy

Definition at line 94 of file YFSFormFactors.h.

◆ exponentialYFSIF()

static double Herwig::YFSFormFactors::exponentialYFSIF ( double  beta0,
double  ombeta0,
double  beta1,
double  ombeta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1,
Energy2  t,
double  charge,
Energy  emin 
)
inlinestatic

Exponentials of the YFS form factors.

The exponential of the YFS form factor for the initial-final dipole

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
ombeta0One minus the velocity of the incoming particle, $1-\beta_0$
ombeta1One minus the velocity of the outgoing particle, $1-\beta_1$
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy

Definition at line 71 of file YFSFormFactors.h.

◆ nbarFF()

static double Herwig::YFSFormFactors::nbarFF ( double  beta1,
double  ombeta1,
double  beta2,
double  ombeta2,
double  charge,
Energy  Emax,
Energy  Emin,
bool  massterms = false 
)
inlinestatic

Crude average multiplicities for initial-final and final-final dipoles.

Crude multiplicity for the final-final dipole

Parameters
beta1Velocity of the first charged particle, $\beta_1$
beta2Velocity of the second charged particle, $\beta_2$.
ombeta1One minus the velocity of the first particle, $1-\beta_1$
ombeta2One minus the velocity of the second particle, $1-\beta_2$
chargeThe product of the charges of the particles in the dipole
EminThe maximum energy for the integral
EmaxThe minimum energy for the integral
masstermsWhether or not to include the mass terms

Definition at line 170 of file YFSFormFactors.h.

◆ nbarIF()

static double Herwig::YFSFormFactors::nbarIF ( double  beta,
double  ombeta,
double  charge,
Energy  Emax,
Energy  Emin,
bool  massterms = false 
)
inlinestatic

Crude multiplicity for the initial-final dipole.

Parameters
betaVelocity of the outgoing charged particle, $\beta$
ombetaOne minus the velocity of the outgoing charged particle, $1-\beta$
chargeThe product of the charges of the particles in the dipole
EminThe maximum energy for the integral
EmaxThe minimum energy for the integral
masstermsWhether or not to include the mass terms

Definition at line 196 of file YFSFormFactors.h.

◆ ReBFF()

static double Herwig::YFSFormFactors::ReBFF ( Energy  m1,
Energy  m2,
Energy2  s,
double  charge,
bool  includegamma = true,
Energy  mgamma = _mgamma 
)
static

The $2\alpha\mathcal{R}B$ function for the final-final dipole.

Parameters
m1The mass of the incoming particle
m2The mass of the outgoing particle
sThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
includegammaInclude the photon mass terms
mgammaThe photon mass,

◆ ReBIF()

static double Herwig::YFSFormFactors::ReBIF ( Energy  m0,
Energy  m1,
Energy2  t,
double  charge,
bool  includegamma = true,
Energy  mgamma = _mgamma 
)
static

The virtual piece for the initial-final and final-final dipoles.

The $2\alpha\mathcal{R}B$ function for the initial-final dipole

Parameters
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
includegammaInclude the photon mass terms
mgammaThe photon mass,

◆ Xijkl()

template<typename T >
static double Herwig::YFSFormFactors::Xijkl ( eta,
yi,
yj,
yk,
yl 
)
inlinestaticprivate

The function $X^{ij}_{kl}(\eta)$ from hep-ph/9606429 for the evaluation of the $A_4$ function.

Parameters
etaThe value of $\eta$
yiThe value of $y_i$
yjThe value of $y_j$
ykThe value of $y_k$
ylThe value of $y_l$

Definition at line 420 of file YFSFormFactors.h.

◆ YFSFF()

static double Herwig::YFSFormFactors::YFSFF ( double  beta1,
double  ombeta1,
double  beta2,
double  ombeta2,
Energy  en1,
Energy  en2,
Energy  m1,
Energy  m2,
Energy2  s,
double  charge,
Energy  emin 
)
inlinestatic

The YFS form factor for the final-final dipole The $2\alpha\tilde{B}$ function for the final-final dipole.

Parameters
beta1Velocity of the first charged particle, $\beta_1$
beta2Velocity of the second charged particle, $\beta_2$.
ombeta1One minus the velocity of the first particle, $1-\beta_1$
ombeta2One minus the velocity of the second particle, $1-\beta_2$
en1The energy of the first particle
en2The energy of the second particle
m1The mass of the first particle
m2The mass of the second particle
sThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy

Definition at line 145 of file YFSFormFactors.h.

◆ YFSIF()

static double Herwig::YFSFormFactors::YFSIF ( double  beta0,
double  ombeta0,
double  beta1,
double  ombeta1,
Energy  en0,
Energy  en1,
Energy  m0,
Energy  m1,
Energy2  t,
double  charge,
Energy  emin 
)
inlinestatic

The YFS form factors for the initial-final and final-final dipoles.

The YFS form factor for the initial-final dipole

Parameters
beta0Velocity of the incoming charged particle, $\beta_0$
beta1Velocity of the outgoing charged particle, $\beta_1$.
ombeta0One minus the velocity of the incoming particle, $1-\beta_0$
ombeta1One minus the velocity of the outgoing particle, $1-\beta_1$
en0The energy of the incoming particle
en1The energy of the outgoing particle
m0The mass of the incoming particle
m1The mass of the outgoing particle
tThe invariant mass of the charged particles
chargeThe product of the charges of the particles in the dipole
eminThe minimum photon energy

Definition at line 121 of file YFSFormFactors.h.

◆ Zij()

template<typename T >
static double Herwig::YFSFormFactors::Zij ( eta,
yi,
yj 
)
inlinestaticprivate

Functions from hep-ph/9606429 for the calculation of the $A_4$ functions.

The function $Z_{ij}(\eta)$ from hep-ph/9606429 for the evaluation of the $A_4$ function.

Parameters
etaThe value of $\eta$
yiThe value of $y_i$
yjThe value of $y_j$

Definition at line 406 of file YFSFormFactors.h.

References Herwig::Math::ReLi2(), and sqr().


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