genie::utils::gsl::d5XSecAR Class Reference

#include <GSLXSecFunc.h>

Inheritance diagram for genie::utils::gsl::d5XSecAR:

Public Member Functions
	d5XSecAR (const XSecAlgorithmI *m, const Interaction *i)
	~d5XSecAR ()
unsigned int	NDim (void) const
double	DoEval (const double *xin) const
ROOT::Math::IBaseFunctionMultiDim *	Clone (void) const
void	SetFlip (bool b)

Private Attributes
const XSecAlgorithmI *	fModel
const Interaction *	fInteraction
bool	flip

Detailed Description

Definition at line 325 of file GSLXSecFunc.h.

Constructor & Destructor Documentation

genie::utils::gsl::d5XSecAR::d5XSecAR	(	const XSecAlgorithmI *	m,
		const Interaction *	i
	)

Definition at line 598 of file GSLXSecFunc.cxx.

                                                      :
ROOT::Math::IBaseFunctionMultiDim(),
fModel(m),
fInteraction(i),
flip(false)
{

}

genie::utils::gsl::d5XSecAR::~d5XSecAR

(

)

Definition at line 607 of file GSLXSecFunc.cxx.

{
}

Member Function Documentation

ROOT::Math::IBaseFunctionMultiDim * genie::utils::gsl::d5XSecAR::Clone

(

void

)

const

Definition at line 689 of file GSLXSecFunc.cxx.

{
  return
    new genie::utils::gsl::d5XSecAR(fModel,fInteraction);
}

double genie::utils::gsl::d5XSecAR::DoEval

(

const double *

xin

)

const

Definition at line 615 of file GSLXSecFunc.cxx.

{
// inputs:
//    x [-]
//    y [-]
// outputs:
//   differential cross section [10^-38 cm^2]
//

  Kinematics * kinematics = fInteraction->KinePtr();
  const TLorentzVector * P4_nu = fInteraction->InitStatePtr()->GetProbeP4(kRfLab);
  double E_nu       = P4_nu->E();

  double E_l       = xin[0];
  double theta_l   = xin[1];
  double phi_l     = xin[2];
  double theta_pi  = xin[3];
  double phi_pi    = xin[4];

  double E_pi= E_nu-E_l;

  double y = E_pi/E_nu;

  double m_l = fInteraction->FSPrimLepton()->Mass();
  if (E_l < m_l) {
    return 0.;
  }

  double m_pi;
  if ( fInteraction->ProcInfo().IsWeakCC() ) {
    m_pi = constants::kPionMass;
  }
  else {
    m_pi = constants::kPi0Mass;
  }


  double p_l = TMath::Sqrt(E_l*E_l - m_l*m_l);
  TVector3 lepton_3vector = TVector3(0,0,0);
  lepton_3vector.SetMagThetaPhi(p_l,theta_l,phi_l);
  TLorentzVector P4_lep    = TLorentzVector(lepton_3vector , E_l );

  double p_pi = TMath::Sqrt(E_pi*E_pi - m_pi*m_pi);
  TVector3 pion_3vector = TVector3(0,0,0);
  pion_3vector.SetMagThetaPhi(p_pi,theta_pi,phi_pi);
  TLorentzVector P4_pion   = TLorentzVector(pion_3vector   , E_pi);

  double Q2 = -(*P4_nu-P4_lep).Mag2();

  double x = Q2/(2*E_pi*constants::kNucleonMass);

  Range1D_t xlim = fInteraction->PhaseSpace().XLim();

  if ( x <  xlim.min || x > xlim.max ) {
    return 0.;
  }

  kinematics->Setx(x);
  kinematics->Sety(y);
  kinematics::UpdateWQ2FromXY(fInteraction);

  kinematics->SetFSLeptonP4(P4_lep );
  kinematics->SetHadSystP4 (P4_pion); // use Hadronic System variable to store pion momentum

  double xsec = fModel->XSec(fInteraction);
  if (xsec>0 && flip) {
    xsec = xsec*-1.0;
  }
  delete P4_nu;
  //return xsec/(1E-38 * units::cm2);
  return xsec;
}

unsigned int genie::utils::gsl::d5XSecAR::NDim

(

void

)

const

Definition at line 611 of file GSLXSecFunc.cxx.

{
  return 5;
}

void genie::utils::gsl::d5XSecAR::SetFlip ( bool  b )

inline

Definition at line 334 of file GSLXSecFunc.h.

{ flip = b; }

Member Data Documentation

const Interaction* genie::utils::gsl::d5XSecAR::fInteraction

private

Definition at line 338 of file GSLXSecFunc.h.

bool genie::utils::gsl::d5XSecAR::flip

private

Definition at line 339 of file GSLXSecFunc.h.

const XSecAlgorithmI* genie::utils::gsl::d5XSecAR::fModel

private

Definition at line 337 of file GSLXSecFunc.h.

---

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

• Generator/src/Physics/XSectionIntegration/GSLXSecFunc.h
• Generator/src/Physics/XSectionIntegration/GSLXSecFunc.cxx