marley::BBBA05SachsFormFactors Class Reference

Inheritance diagram for marley::BBBA05SachsFormFactors:

Public Member Functions
virtual double	GEn (double Q2) override final
virtual double	GEp (double Q2) override final
virtual double	GMn (double Q2) override final
virtual double	GMp (double Q2) override final
Public Member Functions inherited from marley::SachsFormFactors
virtual double	tau (double Q2)

Protected Member Functions
double	bbba05_G (double tau, const std::vector< double > &a_coeffs, const std::vector< double > &b_coeffs)
	Helper function for the form factor calculation.

Detailed Description

Definition at line 87 of file NucleonFormFactors.hh.

Constructor & Destructor Documentation

BBBA05SachsFormFactors()

marley::BBBA05SachsFormFactors::BBBA05SachsFormFactors ( )

inline

Definition at line 91 of file NucleonFormFactors.hh.

{}

Member Function Documentation

bbba05_G()

double marley::BBBA05SachsFormFactors::bbba05_G ( double tau, const std::vector< double > & a_coeffs, const std::vector< double > & b_coeffs )

protected

Helper function for the form factor calculation.

Implements Eq. (6) from Nucl. Phys. B Proc. Suppl. 159, 127 (2006) https://doi.org/10.1016/j.nuclphysbps.2006.08.028

Parameters

tau	Dimensionless negative square of the four-momentum transfer \( \tau = \frac{ Q^{2} }{ 4 m_N^{2} } \)
a_coeffs	Coefficients \( a_k \) of polynomial involving \(\tau^k \) in the numerator
b_coeffs	Coefficients \( b_k \) of polynomial involving \(\tau^k \) in the denominator

Definition at line 38 of file NucleonFormFactors.cc.

{
  double numer = 0.;
  double denom = 1.;
 
  double tau_pow = 1.;
  for ( const auto& a : a_coeffs ) {
    numer += a * tau_pow;
    tau_pow *= tau;
  }
 
  tau_pow = tau;
  for ( const auto& b : b_coeffs ) {
    denom += b * tau_pow;
    tau_pow *= tau;
  }
 
  double ff_G = numer / denom;
  return ff_G;
}

References marley::SachsFormFactors::tau().

Referenced by GEn(), GEp(), GMn(), and GMp().

GEn()

double marley::BBBA05SachsFormFactors::GEn ( double Q2 )

finaloverridevirtual

Neutron electric form factor

Parameters

Q2	Negative square \( Q^{2} \) of the four-momentum transfer (MeV 2)

Implements marley::SachsFormFactors.

Definition at line 75 of file NucleonFormFactors.cc.

                                                    {
  double tau = this->tau( Q2 );
  // TODO: remove hard-coding here and make the parameters configurable
  return this->bbba05_G( tau, { 0., 1.25, 1.30 },
    { -9.86, 305., -758., 802. } );
}

References bbba05_G(), and marley::SachsFormFactors::tau().

GEp()

double marley::BBBA05SachsFormFactors::GEp ( double Q2 )

finaloverridevirtual

Proton electric form factor

Parameters

Q2	Negative square \( Q^{2} \) of the four-momentum transfer (MeV 2)

Implements marley::SachsFormFactors.

Definition at line 61 of file NucleonFormFactors.cc.

                                                    {
  double tau = this->tau( Q2 );
  // TODO: remove hard-coding here and make the parameters configurable
  return marley_utils::g_V * this->bbba05_G( tau, { 1., -0.0578 },
    { 11.1, 13.6, 33. } );
}

References bbba05_G(), and marley::SachsFormFactors::tau().

GMn()

double marley::BBBA05SachsFormFactors::GMn ( double Q2 )

finaloverridevirtual

Neutron magnetic form factor

Parameters

Q2	Negative square \( Q^{2} \) of the four-momentum transfer (MeV 2)

Implements marley::SachsFormFactors.

Definition at line 82 of file NucleonFormFactors.cc.

                                                    {
  double tau = this->tau( Q2 );
  // TODO: remove hard-coding here and make the parameters configurable
  return marley_utils::mu_n * this->bbba05_G( tau, { 1., 1.81 },
    { 14.1, 20.7, 68.7 } );
}

References bbba05_G(), and marley::SachsFormFactors::tau().

GMp()

double marley::BBBA05SachsFormFactors::GMp ( double Q2 )

finaloverridevirtual

Proton magnetic form factor

Parameters

Q2	Negative square \( Q^{2} \) of the four-momentum transfer (MeV 2)

Implements marley::SachsFormFactors.

Definition at line 68 of file NucleonFormFactors.cc.

                                                    {
  double tau = this->tau( Q2 );
  // TODO: remove hard-coding here and make the parameters configurable
  return marley_utils::mu_p * this->bbba05_G( tau, { 1., 0.150 },
    { 11.1, 19.6, 7.54 } );
}

References bbba05_G(), and marley::SachsFormFactors::tau().

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

• /home/sjg/Desktop/marley/include/marley/NucleonFormFactors.hh
• /home/sjg/Desktop/marley/src/NucleonFormFactors.cc