/* This is the header file for the functions that specify the
   nucleon vector and axial vector form factors. */

#ifndef gamma_NN_vertex_h
#define gamma_NN_vertex_h

#include <default.h>
#include <complex.h>
#include <vector.h>
#include <four_vector.h>
#include <dvcs_parameters.h>


#define g_AXIAL 1.267   /* axial coupling constant of the nucleon : PDG98 */


/* constants needed in the parametrization of the 
   nucleon strange form factors */
   
#define M_OMEGA_POLE 0.782
#define M_PHI_POLE 1.019
#define M_Sp_POLE 1.60

#define ANOM_DIM 2.148
#define LAMBDA_SQR 9.73
#define Q0_SQR 0.35

spinor_mat gamma_NN_vertex(int iso, int mu, fvec q);

double form_factor_F1(int iso, double Q_sqr);
double form_factor_F2(int iso, double Q_sqr);
double G_E(int iso, double Q_sqr);    
double G_M(int iso, double Q_sqr);

double form_factor_G_A(double Q_sqr);
double form_factor_G_P(double t);

double form_factor_F1_strange(double Q_sqr);
double form_factor_F2_strange(double Q_sqr);
double Linv_pqcd(double Q_sqr);

#endif