genie::utils::gsl::dXSec_dEDNu_E Class Reference

#include <GSLXSecFunc.h>

Inheritance diagram for genie::utils::gsl::dXSec_dEDNu_E:

Collaboration diagram for genie::utils::gsl::dXSec_dEDNu_E:

Public Member Functions
	dXSec_dEDNu_E (const XSecAlgorithmI *m, const Interaction *i, double DNuMass, double scale=1.)
	~dXSec_dEDNu_E ()
unsigned int	NDim (void) const
double	DoEval (double xin) const
ROOT::Math::IBaseFunctionOneDim *	Clone (void) const
Range1D_t	IntegrationRange (void) const

Private Attributes
const XSecAlgorithmI *	fModel
const Interaction *	fInteraction
double	fDNuMass
double	fScale

Detailed Description

Definition at line 84 of file GSLXSecFunc.h.

Constructor & Destructor Documentation

genie::utils::gsl::dXSec_dEDNu_E::dXSec_dEDNu_E	(	const XSecAlgorithmI *	m,
		const Interaction *	i,
		double	DNuMass,
		double	scale = 1.
	)

Definition at line 114 of file GSLXSecFunc.cxx.

                                :
  ROOT::Math::IBaseFunctionOneDim(),
  fModel(m),
  fInteraction(i),
  fDNuMass(DNuMass),
  fScale(scale)
{

}

genie::utils::gsl::dXSec_dEDNu_E::~dXSec_dEDNu_E

(

)

Definition at line 125 of file GSLXSecFunc.cxx.

{

}

Member Function Documentation

ROOT::Math::IBaseFunctionOneDim * genie::utils::gsl::dXSec_dEDNu_E::Clone

(

void

)

const

Definition at line 175 of file GSLXSecFunc.cxx.

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

double genie::utils::gsl::dXSec_dEDNu_E::DoEval

(

double

xin

)

const

Definition at line 133 of file GSLXSecFunc.cxx.

References genie::units::cm2, genie::kPSEDNufE, genie::kRfLab, LOG, pDEBUG, genie::Kinematics::SetFSLeptonP4(), genie::Kinematics::SetHadSystP4(), and genie::Kinematics::SetQ2().

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

  double DNuEnergy = xin;
  double fDNuMass2 = fDNuMass*fDNuMass;

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

  double ETimesM = E_nu * M_target;
  double EPlusM  = E_nu + M_target;

  double p_DNu = TMath::Sqrt(DNuEnergy*DNuEnergy - fDNuMass2);
  double cos_theta_DNu = (DNuEnergy*(EPlusM) - ETimesM - 0.5*fDNuMass2) / (E_nu * p_DNu);
  double theta_DNu = TMath::ACos(cos_theta_DNu);
  TVector3 DNu_3vector = TVector3(0,0,0);
  DNu_3vector.SetMagThetaPhi(p_DNu, theta_DNu, 0.);
  TLorentzVector P4_DNu = TLorentzVector(DNu_3vector, DNuEnergy);
  kinematics->SetFSLeptonP4(P4_DNu);

  TVector3 target_3vector = P4_nu->Vect() - DNu_3vector;
  double E_target = E_nu + M_target - DNuEnergy;
  TLorentzVector P4_target = TLorentzVector(target_3vector , E_target);
  kinematics->SetHadSystP4(P4_target);
  kinematics->SetQ2(2.*M_target*(E_target-M_target));

  delete P4_nu;
  double xsec = fModel->XSec(fInteraction, kPSEDNufE);
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
  LOG("GSLXSecFunc", pDEBUG) << "xsec(DNuEnergy = " << DNuEnergy << ") = " << xsec;
#endif

  return fScale*xsec/(1E-38 * units::cm2);
}

Range1D_t genie::utils::gsl::dXSec_dEDNu_E::IntegrationRange

(

void

)

const

Definition at line 180 of file GSLXSecFunc.cxx.

References genie::units::A, and genie::kRfLab.

Referenced by genie::COHDNuEventGenerator::GenerateKinematics(), and genie::COHDNuXSec::Integrate().

{
  // look at valid angles section at tech note
  const double E  = fInteraction->InitState().ProbeE(kRfLab);
  const double M = fInteraction->InitState().Tgt().Mass();
  const double M2 = M * M;
  double fDNuMass2 = fDNuMass*fDNuMass;

  const double A = M2 +  2.*M*E;
  const double B = (M+E) * (E*M + 0.5*fDNuMass2);
  const double C = E*E *(M2 + fDNuMass2) + E*M*fDNuMass2 + 0.25*fDNuMass2*fDNuMass2;
  const double D = sqrt(B*B - A*C);

  Range1D_t DNuEnergy((B - D)/A, (B + D)/A);
  return DNuEnergy;

}

unsigned int genie::utils::gsl::dXSec_dEDNu_E::NDim

(

void

)

const

Definition at line 129 of file GSLXSecFunc.cxx.

{
  return 1;
}

Member Data Documentation

double genie::utils::gsl::dXSec_dEDNu_E::fDNuMass

private

Definition at line 100 of file GSLXSecFunc.h.

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

private

Definition at line 99 of file GSLXSecFunc.h.

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

private

Definition at line 98 of file GSLXSecFunc.h.

double genie::utils::gsl::dXSec_dEDNu_E::fScale

private

Definition at line 101 of file GSLXSecFunc.h.

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

• GSLXSecFunc.h
• GSLXSecFunc.cxx