Differential cross section for v+N / vbar+N elastic scattering.
Is a concrete implementation of the XSecAlgorithmI interface.
. More...

#include <AhrensNCELPXSec.h>

Inheritance diagram for genie::AhrensNCELPXSec:

Public Member Functions
	AhrensNCELPXSec ()

	AhrensNCELPXSec (string config)

virtual	~AhrensNCELPXSec ()

double	XSec (const Interaction *i, KinePhaseSpace_t k) const
	Compute the cross section for the input interaction. More...

double	Integral (const Interaction *i) const

bool	ValidProcess (const Interaction *i) const
	Can this cross section algorithm handle the input process? More...

void	Configure (const Registry &config)

void	Configure (string param_set)

Public Member Functions inherited from genie::XSecAlgorithmI
virtual	~XSecAlgorithmI ()

virtual bool	ValidKinematics (const Interaction *i) const
	Is the input kinematical point a physically allowed one? More...

Public Member Functions inherited from genie::Algorithm
virtual	~Algorithm ()

virtual void	FindConfig (void)

virtual const Registry &	GetConfig (void) const

Registry *	GetOwnedConfig (void)

virtual const AlgId &	Id (void) const
	Get algorithm ID. More...

virtual AlgStatus_t	GetStatus (void) const
	Get algorithm status. More...

virtual bool	AllowReconfig (void) const

virtual AlgCmp_t	Compare (const Algorithm *alg) const
	Compare with input algorithm. More...

virtual void	SetId (const AlgId &id)
	Set algorithm ID. More...

virtual void	SetId (string name, string config)

const Algorithm *	SubAlg (const RgKey &registry_key) const

void	AdoptConfig (void)

void	AdoptSubstructure (void)

virtual void	Print (ostream &stream) const
	Print algorithm info. More...

Private Member Functions
void	LoadConfig (void)

Private Attributes
const XSecIntegratorI *	fXSecIntegrator

double	fkAlpha

double	fkGamma

double	fEta

double	fFa0

double	fMa2

double	fMv2

double	fMuP

double	fMuN

Additional Inherited Members
Static Public Member Functions inherited from genie::Algorithm
static string	BuildParamVectKey (const std::string &comm_name, unsigned int i)

static string	BuildParamVectSizeKey (const std::string &comm_name)

Protected Member Functions inherited from genie::XSecAlgorithmI
	XSecAlgorithmI ()

	XSecAlgorithmI (string name)

	XSecAlgorithmI (string name, string config)

Protected Member Functions inherited from genie::Algorithm
	Algorithm ()

	Algorithm (string name)

	Algorithm (string name, string config)

void	Initialize (void)

void	DeleteConfig (void)

void	DeleteSubstructure (void)

Registry *	ExtractLocalConfig (const Registry &in) const

Registry *	ExtractLowerConfig (const Registry &in, const string &alg_key) const
	Split an incoming configuration Registry into a block valid for the sub-algo identified by alg_key. More...

template<class T >
bool	GetParam (const RgKey &name, T &p, bool is_top_call=true) const

template<class T >
bool	GetParamDef (const RgKey &name, T &p, const T &def) const

template<class T >
int	GetParamVect (const std::string &comm_name, std::vector< T > &v, bool is_top_call=true) const
	Handle to load vectors of parameters. More...

int	GetParamVectKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const

int	AddTopRegistry (Registry *rp, bool owns=true)
	add registry with top priority, also update ownership More...

int	AddLowRegistry (Registry *rp, bool owns=true)
	add registry with lowest priority, also update ownership More...

int	MergeTopRegistry (const Registry &r)

int	AddTopRegisties (const vector< Registry * > &rs, bool owns=false)
	Add registries with top priority, also udated Ownerships. More...

Protected Attributes inherited from genie::Algorithm
bool	fAllowReconfig

bool	fOwnsSubstruc
	true if it owns its substructure (sub-algs,...) More...

AlgId	fID
	algorithm name and configuration set More...

vector< Registry * >	fConfVect

vector< bool >	fOwnerships
	ownership for every registry in fConfVect More...

AlgStatus_t	fStatus
	algorithm execution status More...

AlgMap *	fOwnedSubAlgMp
	local pool for owned sub-algs (taken out of the factory pool) More...

Detailed Description

Differential cross section for v+N / vbar+N elastic scattering.
Is a concrete implementation of the XSecAlgorithmI interface.
.

R.E.Hendrick and L.Li, Phys.Rev.D 19:779 (1979) L.A.Ahrens et al., Phys.Rev.D 35:785 (1987)

Author: Costas Andreopoulos <constantinos.andreopoulos cern.ch> University of Liverpool & STFC Rutherford Appleton Laboratory

Fabruary 15, 2005

Definition at line 32 of file AhrensNCELPXSec.h.

Constructor & Destructor Documentation

AhrensNCELPXSec::AhrensNCELPXSec ( )

Definition at line 30 of file AhrensNCELPXSec.cxx.

                                  :
 XSecAlgorithmI("genie::AhrensNCELPXSec")
 {
 
 }

AhrensNCELPXSec::AhrensNCELPXSec ( string config )

Definition at line 36 of file AhrensNCELPXSec.cxx.

                                               :
 XSecAlgorithmI("genie::AhrensNCELPXSec", config)
 {
 
 }

AhrensNCELPXSec::~AhrensNCELPXSec ( )

virtual

Definition at line 42 of file AhrensNCELPXSec.cxx.

 {
 
 }

Member Function Documentation

void AhrensNCELPXSec::Configure ( const Registry & config )

virtual

Configure the algorithm with an external registry The registry is merged with the top level registry if it is owned, Otherwise a copy of it is added with the highest priority

Reimplemented from genie::Algorithm.

Definition at line 142 of file AhrensNCELPXSec.cxx.

 {
   Algorithm::Configure(config);
   this->LoadConfig();
 }

void AhrensNCELPXSec::Configure ( string config )

virtual

Configure the algorithm from the AlgoConfigPool based on param_set string given in input An algorithm contains a vector of registries coming from different xml configuration files, which are loaded according a very precise prioriy This methods will load a number registries in order of priority: 1) "Tunable" parameter set from CommonParametes. This is loaded with the highest prioriry and it is designed to be used for tuning procedure Usage not expected from the user. 2) For every string defined in "CommonParame" the corresponding parameter set will be loaded from CommonParameter.xml 3) parameter set specified by the config string and defined in the xml file of the algorithm 4) if config is not "Default" also the Default parameter set from the same xml file will be loaded Effectively this avoids the repetion of a parameter when it is not changed in the requested configuration

Reimplemented from genie::Algorithm.

Definition at line 148 of file AhrensNCELPXSec.cxx.

 {
   Algorithm::Configure(config);
   this->LoadConfig();
 }

double AhrensNCELPXSec::Integral ( const Interaction * i ) const

virtual

Integrate the model over the kinematic phase space available to the input interaction (kinematical cuts can be included)

Implements genie::XSecAlgorithmI.

Definition at line 130 of file AhrensNCELPXSec.cxx.

 {
   double xsec = fXSecIntegrator->Integrate(this,interaction);
   return xsec;
 }

void AhrensNCELPXSec::LoadConfig ( void )

private

Definition at line 154 of file AhrensNCELPXSec.cxx.

 {
   // alpha and gamma
   double thw ;
   GetParam( "WeinbergAngle", thw ) ;
   double sin2thw = TMath::Power(TMath::Sin(thw), 2);
   fkAlpha = 1.-2.*sin2thw;
   fkGamma = -0.66666667*sin2thw;
 
   // eta and Fa(q2=0)
   GetParam( "EL-Axial-Eta", fEta ) ;
   GetParam( "QEL-FA0", fFa0 ) ;
 
   // axial and vector masses
   double ma, mv ;
   GetParam( "QEL-Ma", ma ) ;
   GetParam( "QEL-Mv", mv ) ;
   fMa2 = TMath::Power(ma,2);
   fMv2 = TMath::Power(mv,2);
 
   // anomalous magnetic moments
   GetParam( "AnomMagnMoment-P", fMuP ) ;
   GetParam( "AnomMagnMoment-N", fMuN ) ;
 
   // load XSec Integrator
   fXSecIntegrator =
       dynamic_cast<const XSecIntegratorI *> (this->SubAlg("XSec-Integrator"));
   assert(fXSecIntegrator);
 }

bool AhrensNCELPXSec::ValidProcess ( const Interaction * i ) const

virtual

Can this cross section algorithm handle the input process?

Implements genie::XSecAlgorithmI.

Definition at line 136 of file AhrensNCELPXSec.cxx.

 {
   if(interaction->TestBit(kISkipProcessChk)) return true;
   return true;
 }

double AhrensNCELPXSec::XSec	(	const Interaction *	i,
		KinePhaseSpace_t	k
	)		const

virtual

Compute the cross section for the input interaction.

Implements genie::XSecAlgorithmI.

Definition at line 47 of file AhrensNCELPXSec.cxx.

 {
   if(! this -> ValidProcess    (interaction) ) return 0.;
   if(! this -> ValidKinematics (interaction) ) return 0.;
 
   const InitialState & init_state = interaction -> InitState();
   const Kinematics &   kinematics = interaction -> Kine();
   const Target &       target     = init_state.Tgt();
 
   double E    = init_state.ProbeE(kRfHitNucRest);
   double Q2   = kinematics.Q2();
   double M    = target.HitNucMass();
   double M2   = TMath::Power(M, 2.);
   double E2   = TMath::Power(E, 2.);
   double qmv2 = TMath::Power(1 + Q2/fMv2, 2);
   double qma2 = TMath::Power(1 + Q2/fMa2, 2);
 
   //-- handle terms changing sign for antineutrinos and isospin rotations
   int nusign  = 1;
   int nucsign = 1;
   int nupdgc  = init_state.ProbePdg();
   int nucpdgc = target.HitNucPdg();
   if( pdg::IsAntiNeutrino(nupdgc) ) nusign  = -1;
   if( pdg::IsNeutron(nucpdgc)     ) nucsign = -1;
 
   //-- compute isoscalar form factor terms
   double Ge0 = 1.5 * fkGamma / qmv2;
   double Gm0 = 1.5 * fkGamma * (fMuP+fMuN) / qmv2;
 
   //-- compute isovector form factor terms
   double Ge1 = 0.5 * fkAlpha / qmv2;
   double Gm1 = 0.5 * fkAlpha * (fMuP-fMuN) / qmv2;
   double Ga1 = -0.5 * fFa0 * (1 + (nucsign) * fEta) / qma2;
 
   //-- compute form factors
   double Ge  = Ge0 + (nucsign) * Ge1;
   double Gm  = Gm0 + (nucsign) * Gm1;
   double Ga  = (nucsign) * Ga1;
   double Ge2 = TMath::Power(Ge,2);
   double Gm2 = TMath::Power(Gm,2);
   double Ga2 = TMath::Power(Ga,2);
 
   //-- compute the free nucleon cross section
   double tau   = 0.25 * Q2/M2;
   double fa    = 1-M*tau/E;
   double fa2   = TMath::Power(fa,2);
   double fb    = tau*(tau+1)*M2/E2;
   double A     = (Ge2/(1+tau))           * (fa2-fb);
   double B     = (Ga2 + tau*Gm2/(1+tau)) * (fa2+fb);
   double C     = 4*tau*(M/E)*Gm*Ga       * fa;
   double xsec0 = 0.5*kGF2/kPi;
   double xsec  = xsec0 * (A + B + (nusign)*C);
 
   LOG("AhrensNCEL", pDEBUG)
     << "dXSec[vN,El]/dQ2 [FreeN](Ev = "<< E<< ", Q2 = "<< Q2 << ") = "<< xsec;
 
   //-- The algorithm computes dxsec/dQ2
   //   Check whether variable tranformation is needed
   if(kps!=kPSQ2fE) {
     double J = utils::kinematics::Jacobian(interaction,kPSQ2fE,kps);
     xsec *= J;
   }
 
   //-- if requested return the free nucleon xsec even for input nuclear tgt
   if( interaction->TestBit(kIAssumeFreeNucleon) ) return xsec;
 
   //-- compute nuclear suppression factor
   //   (R(Q2) is adapted from NeuGEN - see comments therein)
   double R = nuclear::NuclQELXSecSuppression("Default", 0.5, interaction);
 
   //-- number of scattering centers in the target
   int NNucl = (pdg::IsProton(nucpdgc)) ? target.Z() : target.N();
 
   LOG("AhrensNCEL", pDEBUG)
        << "Nuclear suppression factor R(Q2) = " << R << ", NNucl = " << NNucl;
 
   //-- compute nuclear cross section
   xsec *= (R*NNucl);
 
   return xsec;
 }

Member Data Documentation

double genie::AhrensNCELPXSec::fEta

private

Definition at line 56 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fFa0

private

Definition at line 57 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fkAlpha

private

Definition at line 54 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fkGamma

private

Definition at line 55 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fMa2

private

Definition at line 58 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fMuN

private

Definition at line 61 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fMuP

private

Definition at line 60 of file AhrensNCELPXSec.h.

double genie::AhrensNCELPXSec::fMv2

private

Definition at line 59 of file AhrensNCELPXSec.h.

const XSecIntegratorI* genie::AhrensNCELPXSec::fXSecIntegrator

private

Definition at line 52 of file AhrensNCELPXSec.h.

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

Generator/src/Physics/QuasiElastic/XSection/AhrensNCELPXSec.h
Generator/src/Physics/QuasiElastic/XSection/AhrensNCELPXSec.cxx

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation