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Herwig
7.2.1
Decay
WeakCurrents
TwoPionPhotonCurrent.h
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// -*- C++ -*-
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//
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// TwoPionPhotonCurrent.h is a part of Herwig - A multi-purpose Monte Carlo event generator
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// Copyright (C) 2002-2019 The Herwig Collaboration
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//
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// Herwig is licenced under version 3 of the GPL, see COPYING for details.
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// Please respect the MCnet academic guidelines, see GUIDELINES for details.
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//
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#ifndef HERWIG_TwoPionPhotonCurrent_H
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#define HERWIG_TwoPionPhotonCurrent_H
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//
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// This is the declaration of the TwoPionPhotonCurrent class.
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//
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#include "WeakDecayCurrent.h"
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namespace
Herwig
{
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using namespace
ThePEG
;
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class
TwoPionPhotonCurrent
:
public
WeakDecayCurrent
{
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public
:
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TwoPionPhotonCurrent
();
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void
persistentOutput(
PersistentOStream
& os)
const
;
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void
persistentInput(
PersistentIStream
& is,
int
version);
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static
void
Init();
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public
:
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virtual
bool
createMode(
int
icharge,
unsigned
int
imode,DecayPhaseSpaceModePtr mode,
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unsigned
int
iloc,
unsigned
int
ires,
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DecayPhaseSpaceChannelPtr phase,Energy upp);
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virtual
tPDVector
particles(
int
icharge,
unsigned
int
imode,
int
iq,
int
ia);
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virtual
vector<LorentzPolarizationVectorE>
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current(
const
int
imode,
const
int
ichan,Energy & scale,
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const
ParticleVector
& decay,
DecayIntegrator::MEOption
meopt)
const
;
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virtual
bool
accept(vector<int>
id
);
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virtual
unsigned
int
decayMode(vector<int>
id
);
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virtual
void
dataBaseOutput(ofstream & os,
bool
header,
bool
create)
const
;
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protected
:
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virtual
IBPtr
clone
()
const
{
return
new_ptr(*
this
);}
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virtual
IBPtr
fullclone
()
const
{
return
new_ptr(*
this
);}
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protected
:
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virtual
void
doinit();
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private
:
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TwoPionPhotonCurrent
& operator=(
const
TwoPionPhotonCurrent
&) =
delete
;
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private
:
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complex<InvEnergy>
FFunction
(Energy2 q2)
const
{
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complex<InvEnergy2> output(
ZERO
);
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for
(
unsigned
int
ix=0, N=_resweights.size(); ix<N && ix <3;++ix) {
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output -= _resweights[ix]*BreitWigner(q2,ix);
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}
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return
output*_grho*_grhoomegapi*
sqrt
(2.);
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}
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complex<InvEnergy2>
BreitWigner
(Energy2 q2,
unsigned
int
ires)
const
{
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static
const
Complex
ii(0.,1.);
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complex<Energy2> denom;
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if
(ires<_rhomasses.size()) {
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denom = q2-_rhomasses[ires]*_rhomasses[ires]+ii*_rhomasses[ires]*_rhowidths[ires];
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}
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else
if
(ires==10) {
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denom = q2-_omegamass*_omegamass+ii*_omegamass*_omegawidth;
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}
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else
assert(
false
);
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return
1./denom;
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}
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private
:
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Energy2
_grho
;
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InvEnergy
_grhoomegapi
;
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vector<double>
_resweights
;
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bool
_rhoparameters
;
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vector<Energy>
_rhomasses
;
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vector<Energy>
_rhowidths
;
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bool
_omegaparameters
;
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Energy
_omegamass
;
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Energy
_omegawidth
;
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Energy
_intmass
;
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Energy
_intwidth
;
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};
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}
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#endif
/* HERWIG_TwoPionPhotonCurrent_H */
ThePEG::PersistentIStream
Herwig::WeakDecayCurrent
The WeakDecayCurrent class is the base class for the hadronic currents produced in weak decays...
Definition:
WeakDecayCurrent.h:57
sqrt
double sqrt(int x)
Herwig::TwoPionPhotonCurrent::BreitWigner
complex< InvEnergy2 > BreitWigner(Energy2 q2, unsigned int ires) const
Fixed width Breit wigner.
Definition:
TwoPionPhotonCurrent.h:220
ThePEG::Complex
std::complex< double > Complex
Herwig::TwoPionPhotonCurrent::_rhoparameters
bool _rhoparameters
Use local parameters for the rho resonances rather than from the particle data objects.
Definition:
TwoPionPhotonCurrent.h:254
Herwig::TwoPionPhotonCurrent::_grho
Energy2 _grho
Coupling of the rho to the photon, .
Definition:
TwoPionPhotonCurrent.h:238
Herwig::TwoPionPhotonCurrent::_intwidth
Energy _intwidth
Width for the intermediate in the phase-space, this is a technical parameter to improve the phase-spa...
Definition:
TwoPionPhotonCurrent.h:291
Herwig::TwoPionPhotonCurrent::_omegawidth
Energy _omegawidth
The width.
Definition:
TwoPionPhotonCurrent.h:279
ThePEG::PersistentOStream
ThePEG::IBPtr
ThePEG::Ptr< InterfacedBase >::pointer IBPtr
Herwig::TwoPionPhotonCurrent::clone
virtual IBPtr clone() const
Make a simple clone of this object.
Definition:
TwoPionPhotonCurrent.h:170
ThePEG
Herwig::TwoPionPhotonCurrent
This class implements the decay current for via an intermediate .
Definition:
TwoPionPhotonCurrent.h:60
Herwig::DecayIntegrator::MEOption
MEOption
Enum for the matrix element option.
Definition:
DecayIntegrator.h:79
Herwig::TwoPionPhotonCurrent::_intmass
Energy _intmass
Mass for the intermediate in the phase-space, this is a technical parameter to improve the phase-spac...
Definition:
TwoPionPhotonCurrent.h:285
ThePEG::tPDVector
vector< tPDPtr > tPDVector
Herwig::TwoPionPhotonCurrent::_omegaparameters
bool _omegaparameters
use local parameters for the omega rather than from the particle data objects
Definition:
TwoPionPhotonCurrent.h:269
Herwig::TwoPionPhotonCurrent::_resweights
vector< double > _resweights
Weights of the different rho resonances in the current.
Definition:
TwoPionPhotonCurrent.h:248
Herwig::TwoPionPhotonCurrent::_rhomasses
vector< Energy > _rhomasses
Masses of the resonances.
Definition:
TwoPionPhotonCurrent.h:259
Herwig::TwoPionPhotonCurrent::_omegamass
Energy _omegamass
The mass.
Definition:
TwoPionPhotonCurrent.h:274
Herwig::TwoPionPhotonCurrent::_grhoomegapi
InvEnergy _grhoomegapi
Coupling of the rho to the omega and a pion, .
Definition:
TwoPionPhotonCurrent.h:243
Herwig
-*- C++ -*-
Definition:
BasicConsistency.h:17
Herwig::TwoPionPhotonCurrent::FFunction
complex< InvEnergy > FFunction(Energy2 q2) const
Calculate the function at a given scale.
Definition:
TwoPionPhotonCurrent.h:205
Herwig::TwoPionPhotonCurrent::fullclone
virtual IBPtr fullclone() const
Make a clone of this object, possibly modifying the cloned object to make it sane.
Definition:
TwoPionPhotonCurrent.h:176
ThePEG::ParticleVector
vector< PPtr > ParticleVector
Herwig::TwoPionPhotonCurrent::_rhowidths
vector< Energy > _rhowidths
Widths of the resonances.
Definition:
TwoPionPhotonCurrent.h:264
ZERO
constexpr ZeroUnit ZERO
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