genie::SuSAv2MECPXSec Class Reference

Computes the SuSAv2-MEC model differential cross section. Uses precomputed hadron tensor tables. Is a concrete implementation of the XSecAlgorithmI interface. More...

#include <SuSAv2MECPXSec.h>

Inheritance diagram for genie::SuSAv2MECPXSec:

Collaboration diagram for genie::SuSAv2MECPXSec:

Public Member Functions
	SuSAv2MECPXSec ()
	SuSAv2MECPXSec (string config)
virtual	~SuSAv2MECPXSec ()
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 config)
double	PairRatio (const Interaction *i, const std::string &final_state_ratio="pnFraction") const
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)
	Load algorithm configuration. More...
double	Qvalue (const Interaction &interaction) const

Private Attributes
double	fXSecCCScale
	External scaling factor for this cross section. More...
double	fXSecNCScale
double	fXSecEMScale
const genie::HadronTensorModelI *	fHadronTensorModel
string	fKFTable
double	fEbHe
double	fEbLi
double	fEbC
double	fEbO
double	fEbMg
double	fEbAr
double	fEbCa
double	fEbFe
double	fEbNi
double	fEbSn
double	fEbAu
double	fEbPb
const XSecIntegratorI *	fXSecIntegrator
	GSL numerical integrator. More...
const XSecScaleI *	fMECScaleAlg
const QvalueShifter *	fQvalueShifter

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)
static string	BuildParamMatKey (const std::string &comm_name, unsigned int i, unsigned int j)
static string	BuildParamMatRowSizeKey (const std::string &comm_name)
static string	BuildParamMatColSizeKey (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
template<class T >
int	GetParamMat (const std::string &comm_name, TMatrixT< T > &mat, bool is_top_call=true) const
	Handle to load matrix of parameters. More...
template<class T >
int	GetParamMatSym (const std::string &comm_name, TMatrixTSym< T > &mat, bool is_top_call=true) const
int	GetParamMatKeys (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

Computes the SuSAv2-MEC model differential cross section. Uses precomputed hadron tensor tables. Is a concrete implementation of the XSecAlgorithmI interface.

Author

Steven Gardiner <gardiner fnal.gov> Fermi National Acclerator Laboratory

Stephen Dolan <stephen.joseph.dolan cern.ch> European Organization for Nuclear Research (CERN)

References:

G.D. Megias et al., "Meson-exchange currents and quasielastic predictions for charged-current neutrino-12C scattering in the superscaling approach," PRD 91 (2015) 073004

Created:

November 2, 2018

License:

Copyright (c) 2003-2024, The GENIE Collaboration For the full text of the license visit http://copyright.genie-mc.org or see $GENIE/LICENSE

Definition at line 40 of file SuSAv2MECPXSec.h.

Constructor & Destructor Documentation

SuSAv2MECPXSec::SuSAv2MECPXSec

(

)

Definition at line 28 of file SuSAv2MECPXSec.cxx.

                               : XSecAlgorithmI("genie::SuSAv2MECPXSec")
{
}

SuSAv2MECPXSec::SuSAv2MECPXSec

(

string

config

)

Definition at line 32 of file SuSAv2MECPXSec.cxx.

  : XSecAlgorithmI("genie::SuSAv2MECPXSec", config)
{
}

SuSAv2MECPXSec::~SuSAv2MECPXSec ( )

virtual

Definition at line 37 of file SuSAv2MECPXSec.cxx.

{
}

Member Function Documentation

void SuSAv2MECPXSec::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 401 of file SuSAv2MECPXSec.cxx.

References genie::Algorithm::Configure(), and LoadConfig().

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

void genie::SuSAv2MECPXSec::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.

double SuSAv2MECPXSec::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 288 of file SuSAv2MECPXSec.cxx.

References fXSecIntegrator, and genie::XSecIntegratorI::Integrate().

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

void SuSAv2MECPXSec::LoadConfig ( void  )

private

Load algorithm configuration.

Definition at line 413 of file SuSAv2MECPXSec.cxx.

References fEbAr, fEbAu, fEbC, fEbCa, fEbFe, fEbHe, fEbLi, fEbMg, fEbNi, fEbO, fEbPb, fEbSn, fHadronTensorModel, fKFTable, fMECScaleAlg, fQvalueShifter, fXSecCCScale, fXSecEMScale, fXSecIntegrator, fXSecNCScale, genie::Algorithm::GetConfig(), genie::Algorithm::GetParam(), genie::Algorithm::GetParamDef(), genie::Algorithm::Id(), LOG, pERROR, and genie::Algorithm::SubAlg().

Referenced by Configure().

{
  bool good_config = true ;
  // Cross section scaling factor
  GetParamDef("MEC-CC-XSecScale", fXSecCCScale, 1.) ;
  GetParamDef("MEC-NC-XSecScale", fXSecNCScale, 1.) ;
  GetParamDef("MEC-EM-XSecScale", fXSecEMScale, 1.) ;

  fHadronTensorModel = dynamic_cast<const HadronTensorModelI*> ( this->SubAlg("HadronTensorAlg") );
  if( !fHadronTensorModel ) {
    good_config = false ;
    LOG("SuSAv2MECPXSec", pERROR) << "The required HadronTensorAlg does not exist. AlgoID is : " << SubAlg("HadronTensorAlg")->Id();
  }

  fXSecIntegrator = dynamic_cast<const XSecIntegratorI*> (this->SubAlg("NumericalIntegrationAlg"));
  if( !fXSecIntegrator ) {
    good_config = false ;
    LOG("SuSAv2MECPXSec", pERROR) << "The required NumericalIntegrationAlg does not exist. AlgId is : " << SubAlg("NumericalIntegrationAlg")->Id() ;
  }

  //Fermi momentum tables for scaling
  this->GetParam( "FermiMomentumTable", fKFTable);

  //binding energy lookups for scaling
  this->GetParam( "RFG-NucRemovalE@Pdg=1000020040", fEbHe );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000030060", fEbLi );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000060120", fEbC  );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000080160", fEbO  );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000120240", fEbMg );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000180400", fEbAr );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000200400", fEbCa );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000260560", fEbFe );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000280580", fEbNi );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000501190", fEbSn );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000791970", fEbAu );
  this->GetParam( "RFG-NucRemovalE@Pdg=1000822080", fEbPb );

  // Read optional MECScaleVsW:
  fMECScaleAlg = nullptr;
  if( GetConfig().Exists("MECScaleAlg") ) {
    fMECScaleAlg = dynamic_cast<const XSecScaleI *> ( this->SubAlg("MECScaleAlg") );
    if( !fMECScaleAlg ) {
      good_config = false ;
      LOG("Susav2MECPXSec", pERROR) << "The required MECScaleAlg cannot be casted. AlgID is : " << SubAlg("MECScaleAlg")->Id() ;
    }
  }

  // Read optional QvalueShifter:
  fQvalueShifter = nullptr;
  if( GetConfig().Exists("QvalueShifterAlg") ) {
    fQvalueShifter = dynamic_cast<const QvalueShifter *> ( this->SubAlg("QvalueShifterAlg") );
    if( !fQvalueShifter ) {
      good_config = false ;
      LOG("SuSAv2MECPXSec", pERROR) << "The required QvalueShifterAlg does not exist. AlgId is : " << SubAlg("QvalueShifterAlg")->Id() ;
    }
  }

  if( ! good_config ) {
    LOG("SuSAv2MECPXSec", pERROR) << "Configuration has failed.";
    exit(78) ;
  }

}

double SuSAv2MECPXSec::PairRatio	(	const Interaction *	i,
		const std::string &	final_state_ratio = "pnFraction"
	)		const

Definition at line 173 of file SuSAv2MECPXSec.cxx.

References genie::LabFrameHadronTensorI::dSigma_dT_dCosTheta_rosenbluth(), fHadronTensorModel, genie::Interaction::FSPrimLepton(), genie::Kinematics::GetKV(), genie::utils::mec::Getq0q3FromTlCostl(), genie::HadronTensorModelI::GetTensor(), genie::Interaction::InitState(), genie::pdg::IsAntiNeutrino(), genie::ProcessInfo::IsEM(), genie::pdg::IsNeutrino(), genie::kHT_MEC_EM, genie::kHT_MEC_EM_pn, genie::kHT_MEC_EM_pp, genie::kHT_MEC_FullAll, genie::kHT_MEC_Fullpn, genie::kHT_Undefined, genie::Interaction::Kine(), genie::kKVctl, genie::kKVTl, genie::kPdgTgtC12, genie::kRfLab, LOG, genie::InitialState::ProbeE(), genie::InitialState::ProbePdg(), genie::Interaction::ProcInfo(), pWARN, genie::HadronTensorI::q0Max(), genie::HadronTensorI::q0Min(), genie::HadronTensorI::qMagMax(), genie::HadronTensorI::qMagMin(), and Qvalue().

{

  // Currently we only have the relative pair contributions for C12.
  // We hope to add mode later, but for the moment assume the relative
  // contributions are A-independant.

  int probe_pdg = interaction->InitState().ProbePdg();

  HadronTensorType_t tensor_type = kHT_Undefined;
  HadronTensorType_t pn_tensor_type = kHT_Undefined;
  HadronTensorType_t pp_tensor_type = kHT_Undefined;

  if ( pdg::IsNeutrino(probe_pdg) || pdg::IsAntiNeutrino(probe_pdg) ) {
    tensor_type = kHT_MEC_FullAll;
    pn_tensor_type = kHT_MEC_Fullpn;
  }
  else {
    // If the probe is not a neutrino, assume that it's an electron
    // For the moment all electron interactions are pp final state
    tensor_type = kHT_MEC_EM;
    pn_tensor_type = kHT_MEC_EM_pn;
    pp_tensor_type = kHT_MEC_EM_pp;
  }

  // The SuSAv2-MEC hadron tensors are defined using the same conventions
  // as the Valencia MEC model, so we can use the same sort of tensor
  // object to describe them.
  const LabFrameHadronTensorI* tensor
    = dynamic_cast<const LabFrameHadronTensorI*>( fHadronTensorModel->GetTensor(kPdgTgtC12,
    tensor_type) );

  const LabFrameHadronTensorI* tensor_pn
    = dynamic_cast<const LabFrameHadronTensorI*>( fHadronTensorModel->GetTensor(kPdgTgtC12,
    pn_tensor_type) );

  const LabFrameHadronTensorI* tensor_pp
    = dynamic_cast<const LabFrameHadronTensorI*>( fHadronTensorModel->GetTensor(kPdgTgtC12,
    pp_tensor_type) );

  // If retrieving the tensor failed, complain and return zero
  if ( !tensor ) {
    LOG("SuSAv2MEC", pWARN) << "Failed to load a hadronic tensor for the"
      " nuclide " << kPdgTgtC12;
    return 0.;
  }

  if ( !tensor_pn ) {
    LOG("SuSAv2MEC", pWARN) << "Failed to load pn hadronic tensor for the"
      " nuclide " << kPdgTgtC12;
    return 0.;
  }

  if ( !tensor_pp && interaction->ProcInfo().IsEM() ) {
    LOG("SuSAv2MEC", pWARN) << "Failed to load pp hadronic tensor for the"
      " nuclide " << kPdgTgtC12;
    return 0.;
  }

  // Check that the input kinematical point is within the range
  // in which hadron tensors are known (for chosen target)
  double Ev    = interaction->InitState().ProbeE(kRfLab);
  double Tl    = interaction->Kine().GetKV(kKVTl);
  double costl = interaction->Kine().GetKV(kKVctl);
  double ml    = interaction->FSPrimLepton()->Mass();
  double Q0    = 0.;
  double Q3    = 0.;

  genie::utils::mec::Getq0q3FromTlCostl(Tl, costl, Ev, ml, Q0, Q3);

  double Q0min = tensor->q0Min();
  double Q0max = tensor->q0Max();
  double Q3min = tensor->qMagMin();
  double Q3max = tensor->qMagMax();
  if (Q0 < Q0min || Q0 > Q0max || Q3 < Q3min || Q3 > Q3max) {
    return 1.0;
  }

  // The Q-Value essentially corrects q0 to account for nuclear
  // binding energy in the Valencia model but this effect is already
  // in Guille's tensors so its set it to 0.
  // However, additional corrections may be necessary:
  double Delta_Q_value = Qvalue( * interaction ) ;

  // Compute the cross section using the hadron tensor
  double xsec_all = tensor->dSigma_dT_dCosTheta_rosenbluth(interaction, Delta_Q_value);

  double ratio;

  if (final_state_ratio == "pnFraction") { // pnFraction will be calculated by default
    double xsec_pn = tensor_pn->dSigma_dT_dCosTheta_rosenbluth(interaction, Delta_Q_value);

    //hadron tensor precision can sometimes lead to 0 xsec_pn but finite xsec
    //seems to cause issues downstream ...
    if(xsec_pn==0) xsec_pn = 0.00001*xsec_all;

    double pn_ratio = (1e10*xsec_pn)/(1e10*xsec_all);

    ratio = pn_ratio;

  } else if (final_state_ratio == "ppFraction") {
    double xsec_pp = tensor_pp->dSigma_dT_dCosTheta_rosenbluth(interaction, Delta_Q_value);

    if(xsec_pp==0) xsec_pp = 0.00001*xsec_all;

    double pp_ratio = (1e10*xsec_pp)/(1e10*xsec_all);

    ratio = pp_ratio;

  }

  return ratio;
}

double SuSAv2MECPXSec::Qvalue ( const Interaction &  interaction ) const

private

Todo:

Add more hadron tensors so this scaling is not so terrible

Definition at line 317 of file SuSAv2MECPXSec.cxx.

References fEbAr, fEbC, fEbFe, fEbHe, fEbLi, fEbMg, fEbO, fEbPb, fEbSn, fQvalueShifter, genie::Interaction::InitState(), genie::pdg::IonPdgCodeToA(), genie::ProcessInfo::IsEM(), genie::kPdgTgtC12, genie::Target::Pdg(), genie::InitialState::ProbePdg(), genie::Interaction::ProcInfo(), genie::utils::mec::Qvalue(), and genie::InitialState::Tgt().

Referenced by PairRatio(), and XSec().

{
  // Get the hadron tensor for the selected nuclide. Check the probe PDG code
  // to know whether to use the tensor for CC neutrino scattering or for
  // electron scattering
  int target_pdg = interaction.InitState().Tgt().Pdg();
  int probe_pdg = interaction.InitState().ProbePdg();
  int tensor_pdg = kPdgTgtC12;
  int A_request = pdg::IonPdgCodeToA(target_pdg);

  double Eb_tgt=0;
  double Eb_ten=0;

  /// \todo Add more hadron tensors so this scaling is not so terrible
  // At the moment all we have is Carbon so this is all just a place holder ...
  if ( A_request == 4 ) {
    Eb_tgt=fEbHe; Eb_ten=fEbC;
    // This is for helium 4, but use carbon tensor, may not be ideal ...
  }
  else if (A_request < 9) {
    Eb_tgt=fEbLi; Eb_ten=fEbC;
  }
  else if (A_request >= 9 && A_request < 15) {
    Eb_tgt=fEbC; Eb_ten=fEbC;
  }
  else if(A_request >= 15 && A_request < 22) {
    //tensor_pdg = kPdgTgtO16;
    // Oxygen tensor has some issues - xsec @ 50 GeV = 45.2835 x 1E-38 cm^2
    // This is ~ 24 times higher than C
    // I think it's just a missing scale factor but I need to check.
    Eb_tgt=fEbO; Eb_ten=fEbC;
  }
  else if(A_request >= 22 && A_request < 40) {
    Eb_tgt=fEbMg; Eb_ten=fEbC;
  }
  else if(A_request >= 40 && A_request < 56) {
    Eb_tgt=fEbAr; Eb_ten=fEbC;
  }
  else if(A_request >= 56 && A_request < 119) {
    Eb_tgt=fEbFe; Eb_ten=fEbC;
  }
  else if(A_request >= 119 && A_request < 206) {
    Eb_tgt=fEbSn; Eb_ten=fEbC;
  }
  else if(A_request >= 206) {
    Eb_tgt=fEbPb; Eb_ten=fEbC;
  }

  // SD: The Q-Value essentially corrects q0 to account for nuclear
  // binding energy in the Valencia model but this effect is already
  // in Guille's tensors so I'll set it to 0.
  // However, if I want to scale I need to account for the altered
  // binding energy. To first order I can use the Delta_Q_value for this.
  // But this is 2p2h - so binding energy counts twice - use 2*1p1h
  // value (although what should be done here is still not clear).

  double Delta_Q_value = 2*(Eb_tgt-Eb_ten);

  // Apply Qvalue relative shift if needed:
  if( fQvalueShifter ) {
    // We have the option to add an additional shift on top of the binding energy correction
    // The QvalueShifter, is a relative shift to the Q_value.
    // The Q_value was already taken into account in the hadron tensor. Here we recalculate it
    // to get the right absolute shift.
    double tensor_Q_value = genie::utils::mec::Qvalue(tensor_pdg,probe_pdg);
    double total_Q_value = tensor_Q_value + Delta_Q_value ;
    double Q_value_shift = total_Q_value * fQvalueShifter -> Shift( interaction.InitState().Tgt() ) ;
    Delta_Q_value += Q_value_shift ;
  }

  // We apply an extra Q-value shift here to account for differences between
  // the 12C EM MEC tensors currently in use (which have a "baked in" Q-value
  // already incorporated) and the treatment in Guille's thesis. Differences
  // between the two lead to a few-tens-of-MeV shift in the energy transfer
  // distribution for EM MEC. The shift is done in terms of the binding energy
  // value associated with the original tensor (Eb_ten). Corrections for
  // scaling to a different target are already handled above.
  // - S. Gardiner, 1 July 2020
  bool isEM = interaction.ProcInfo().IsEM();
  if ( isEM ) Delta_Q_value -= 2. * Eb_ten;

  return Delta_Q_value ;
}

bool SuSAv2MECPXSec::ValidProcess ( const Interaction *  i ) const

virtual

Can this cross section algorithm handle the input process?

Implements genie::XSecAlgorithmI.

Definition at line 294 of file SuSAv2MECPXSec.cxx.

References genie::Interaction::InitState(), genie::pdg::IsAntiNeutrino(), genie::pdg::IsChargedLepton(), genie::ProcessInfo::IsEM(), genie::ProcessInfo::IsMEC(), genie::pdg::IsNeutrino(), genie::ProcessInfo::IsWeakCC(), genie::kISkipProcessChk, genie::InitialState::ProbePdg(), and genie::Interaction::ProcInfo().

Referenced by XSec().

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

  const ProcessInfo& proc_info = interaction->ProcInfo();
  if ( !proc_info.IsMEC() ) {
    return false;
  }

  int probe = interaction->InitState().ProbePdg();

  bool is_nu = pdg::IsNeutrino( probe );
  bool is_nub = pdg::IsAntiNeutrino( probe );
  bool is_chgl = pdg::IsChargedLepton( probe );

  bool prc_ok = ( proc_info.IsWeakCC() && (is_nu || is_nub) )
    || ( proc_info.IsEM() && is_chgl );

  if ( !prc_ok ) return false;

  return true;
}

double SuSAv2MECPXSec::XSec ( const Interaction *  i, KinePhaseSpace_t  k  ) const

virtual

Compute the cross section for the input interaction.

Implements genie::XSecAlgorithmI.

Definition at line 41 of file SuSAv2MECPXSec.cxx.

References genie::KinePhaseSpace::AsString(), genie::LabFrameHadronTensorI::dSigma_dT_dCosTheta_rosenbluth(), fHadronTensorModel, genie::FermiMomentumTable::FindClosestKF(), fKFTable, fMECScaleAlg, genie::Interaction::FSPrimLepton(), fXSecCCScale, fXSecEMScale, fXSecNCScale, genie::Kinematics::GetKV(), genie::utils::mec::Getq0q3FromTlCostl(), genie::XSecScaleI::GetScaling(), genie::FermiMomentumTablePool::GetTable(), genie::HadronTensorModelI::GetTensor(), genie::Target::HitNucPdg(), genie::Interaction::InitState(), genie::FermiMomentumTablePool::Instance(), genie::pdg::IonPdgCodeToA(), genie::pdg::IonPdgCodeToZ(), genie::pdg::IsAntiNeutrino(), genie::ProcessInfo::IsEM(), genie::pdg::IsNeutrino(), genie::ProcessInfo::IsWeakCC(), genie::ProcessInfo::IsWeakNC(), genie::kHT_MEC_EM, genie::kHT_MEC_FullAll, genie::kHT_Undefined, genie::Interaction::Kine(), genie::kKVctl, genie::kKVTl, genie::controls::kMinQ2Limit, genie::kPdgClusterNP, genie::kPdgProton, genie::kPdgTgtC12, genie::kPSTlctl, genie::kRfLab, LOG, pDEBUG, genie::Target::Pdg(), genie::InitialState::ProbeE(), genie::InitialState::ProbePdg(), genie::Interaction::ProcInfo(), pWARN, genie::HadronTensorI::q0Max(), genie::HadronTensorI::q0Min(), genie::utils::kinematics::Q2(), genie::HadronTensorI::qMagMax(), genie::HadronTensorI::qMagMin(), Qvalue(), genie::InitialState::Tgt(), and ValidProcess().

{
  // Don't try to do the calculation if we've been handed an interaction that
  // doesn't make sense
  if ( !this->ValidProcess(interaction) ) return 0.;

  // Get the hadron tensor for the selected nuclide. Check the probe PDG code
  // to know whether to use the tensor for CC neutrino scattering or for
  // electron scattering
  int target_pdg = interaction->InitState().Tgt().Pdg();
  int probe_pdg = interaction->InitState().ProbePdg();
  int A_request = pdg::IonPdgCodeToA(target_pdg);
  int Z_request = pdg::IonPdgCodeToZ(target_pdg);
  bool need_to_scale = false;

  HadronTensorType_t tensor_type = kHT_Undefined;
  if ( pdg::IsNeutrino(probe_pdg) || pdg::IsAntiNeutrino(probe_pdg) ) {
    tensor_type = kHT_MEC_FullAll;
    //pn_tensor_type = kHT_MEC_Fullpn;
    //tensor_type = kHT_MEC_FullAll_wImag;
    //pn_tensor_type = kHT_MEC_FullAll_wImag;
  }
  else {
    // If the probe is not a neutrino, assume that it's an electron
    // For the moment all electron interactions are pp final state
    tensor_type = kHT_MEC_EM;
    //pn_tensor_type = kHT_MEC_EM;
  }

  // Currently we only have the relative pair contributions for C12.
  int tensor_pdg = kPdgTgtC12;
  if(tensor_pdg != target_pdg) need_to_scale = true;

  // The SuSAv2-MEC hadron tensors are defined using the same conventions
  // as the Valencia MEC model, so we can use the same sort of tensor
  // object to describe them.
  const LabFrameHadronTensorI* tensor
    = dynamic_cast<const LabFrameHadronTensorI*>( fHadronTensorModel->GetTensor(tensor_pdg,
    tensor_type) );

  // If retrieving the tensor failed, complain and return zero
  if ( !tensor ) {
    LOG("SuSAv2MEC", pWARN) << "Failed to load a hadronic tensor for the"
      " nuclide " << tensor_pdg;
    return 0.;
  }

  // Check that the input kinematical point is within the range
  // in which hadron tensors are known (for chosen target)
  double Ev    = interaction->InitState().ProbeE(kRfLab);
  double Tl    = interaction->Kine().GetKV(kKVTl);
  double costl = interaction->Kine().GetKV(kKVctl);
  double ml    = interaction->FSPrimLepton()->Mass();
  double Q0    = 0.;
  double Q3    = 0.;

  // The Q-Value essentially corrects q0 to account for nuclear
  // binding energy in the Valencia model but this effect is already
  // in Guille's tensors so its set it to 0.
  // However, additional corrections may be necessary:
  double Delta_Q_value = Qvalue( * interaction ) ;

  genie::utils::mec::Getq0q3FromTlCostl(Tl, costl, Ev, ml, Q0, Q3);

  double Q0min = tensor->q0Min();
  double Q0max = tensor->q0Max();
  double Q3min = tensor->qMagMin();
  double Q3max = tensor->qMagMax();
  if (Q0-Delta_Q_value < Q0min || Q0-Delta_Q_value > Q0max || Q3 < Q3min || Q3 > Q3max) {
    return 0.0;
  }

  // *** Enforce the global Q^2 cut (important for EM scattering) ***
  // Choose the appropriate minimum Q^2 value based on the interaction
  // mode (this is important for EM interactions since the differential
  // cross section blows up as Q^2 --> 0)
  double Q2min = genie::controls::kMinQ2Limit; // CC/NC limit
  if ( interaction->ProcInfo().IsEM() ) Q2min = genie::utils::kinematics
    ::electromagnetic::kMinQ2Limit; // EM limit

  // Neglect shift due to binding energy. The cut is on the actual
  // value of Q^2, not the effective one to use in the tensor contraction.
  double Q2 = Q3*Q3 - Q0*Q0;
  if ( Q2 < Q2min ) return 0.;

  // By default, we will compute the full cross-section. If a {p,n} hit
  // dinucleon was set we will calculate the cross-section for that
  // component only

  bool pn = (interaction->InitState().Tgt().HitNucPdg() == kPdgClusterNP);

  // Compute the cross section using the hadron tensor
  double xsec = tensor->dSigma_dT_dCosTheta_rosenbluth(interaction, Delta_Q_value);

  // This scaling should be okay-ish for the total xsec, but it misses
  // the energy shift. To get this we should really just build releveant
  // hadron tensors but there may be some ways to approximate it.
  // For more details see Guille's thesis: https://idus.us.es/xmlui/handle/11441/74826
  if ( need_to_scale ) {
    FermiMomentumTablePool * kftp = FermiMomentumTablePool::Instance();
    const FermiMomentumTable * kft = kftp->GetTable(fKFTable);
    double KF_tgt = kft->FindClosestKF(target_pdg, kPdgProton);
    double KF_ten = kft->FindClosestKF(tensor_pdg, kPdgProton);
    LOG("SuSAv2MEC", pDEBUG) << "KF_tgt = " << KF_tgt;
    LOG("SuSAv2MEC", pDEBUG) << "KF_ten = " << KF_ten;
    double A_ten  = pdg::IonPdgCodeToA(tensor_pdg);
    double scaleFact = (A_request/A_ten)*(KF_tgt/KF_ten)*(KF_tgt/KF_ten);
    xsec *= scaleFact;
  }

  // Apply given overall scaling factor

  const ProcessInfo& proc_info = interaction->ProcInfo();
  if( proc_info.IsWeakCC() ) xsec *= fXSecCCScale;
  else if( proc_info.IsWeakNC() ) xsec *= fXSecNCScale;
  else if( proc_info.IsEM() ) xsec *= fXSecEMScale;

  // Scale given a scaling algorithm:
  if( fMECScaleAlg ) xsec *= fMECScaleAlg->GetScaling( * interaction ) ;

  if ( kps != kPSTlctl ) {
    LOG("SuSAv2MEC", pWARN)
      << "Doesn't support transformation from "
      << KinePhaseSpace::AsString(kPSTlctl) << " to "
      << KinePhaseSpace::AsString(kps);
    xsec = 0.;
  }

  return xsec;
}

Member Data Documentation

double genie::SuSAv2MECPXSec::fEbAr

private

Definition at line 86 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbAu

private

Definition at line 91 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig().

double genie::SuSAv2MECPXSec::fEbC

private

Definition at line 83 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbCa

private

Definition at line 87 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig().

double genie::SuSAv2MECPXSec::fEbFe

private

Definition at line 88 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbHe

private

Definition at line 81 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbLi

private

Definition at line 82 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbMg

private

Definition at line 85 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbNi

private

Definition at line 89 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig().

double genie::SuSAv2MECPXSec::fEbO

private

Definition at line 84 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbPb

private

Definition at line 92 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fEbSn

private

Definition at line 90 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

const genie::HadronTensorModelI* genie::SuSAv2MECPXSec::fHadronTensorModel

private

Definition at line 75 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), PairRatio(), and XSec().

string genie::SuSAv2MECPXSec::fKFTable

private

Definition at line 78 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and XSec().

const XSecScaleI* genie::SuSAv2MECPXSec::fMECScaleAlg

private

Definition at line 97 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and XSec().

const QvalueShifter* genie::SuSAv2MECPXSec::fQvalueShifter

private

Definition at line 98 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and Qvalue().

double genie::SuSAv2MECPXSec::fXSecCCScale

private

External scaling factor for this cross section.

Definition at line 71 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and XSec().

double genie::SuSAv2MECPXSec::fXSecEMScale

private

Definition at line 73 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and XSec().

const XSecIntegratorI* genie::SuSAv2MECPXSec::fXSecIntegrator

private

GSL numerical integrator.

Definition at line 95 of file SuSAv2MECPXSec.h.

Referenced by Integral(), and LoadConfig().

double genie::SuSAv2MECPXSec::fXSecNCScale

private

Definition at line 72 of file SuSAv2MECPXSec.h.

Referenced by LoadConfig(), and XSec().

---

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

• SuSAv2MECPXSec.h
• SuSAv2MECPXSec.cxx