/* This is the header file that contains the parameters for 
   pion photoproduction. */

#ifndef t_piprod_parameters_h
#define t_piprod_parameters_h



#define COUPLING 2        /* 1 : G1, G2 coupling */
                          /* 2:  GM, GE coupling */

#define PI_M 135.0
                          /* pion mass (in MeV) */
                          /* 139.6 */
#define PIO_M 135.0        
                          /* neutral pion mass (in MeV) */
                          /* 135.0 */
#define PIM_M 138.       
                          /* pion mass (in MeV) used in resonant multipoles */
                          /* 139.6 */ 
                          /* 138. averaged mass when working 
                             with neutral pions */
                          
#define NU_M 939.         /* nucleon mass in MeV */
#define DEL_M 1218.76
                          /* delta mass in MeV */
                          /* 1218.76 relativistic, unitarized background
                                     for charged pion channels */  
                          /* 1218.02 relativistic, unitarized background
                                     for neutral pion channels */  
   
#define M_p33 DEL_M

#define OMEGA_M 782.      
                          /* omega meson mass in MeV */
#define RHO_M 770.      
                          /* rho meson mass in MeV */

#define ELEC 0.302862     
                          /* electric charge e */
			  /* with pow(e, 2) / (4 * PI) = 1 / 137 */
#define CONV 1.           /* CONV = 1. turns ON the convection part in the 
                                       nucleon born diagrams,
                             CONV = 0. turns OFF the convection part in the 
                                       nucleon born diagrams */
#define ANTI_NUCL 1.      /* ANTI_NUCL = 1. turns ON the antinucleon 
                                            contribution,
                             ANTI_NUCL = 0. turns OFF the antinucleon 
                                         contribution */

#define P_MAGN 2.79       
                          /* magnetic moment of proton */
#define N_MAGN (- 1.91)   
                          /* magnetic moment of neutron */
#define F_PINN 1.00265  
                          /* coupling constant f_pinn */
			  /* with pow(f_pinn, 2) / (4 * PI) = 0.08 */
                          /* 1.00265 */ /* 0.97 */     
#define G_OMEGANN 15.85    
                          /* coupling constant g_omegann */
			  /* with pow(g_omegann, 2) / (4 * PI) = 24.9 */
                          /* 17.7 */ /*  15.85 */  
#define G_OMPIGA 0.314
                          /* coupling constant g_omega-pi-gamma */
                          /* 0.314 */ 
#define G_RHONN 2.63
                          /* vector coupling constant g_rhonn */
			  /* with pow(g_omegann, 2) / (4 * PI) = 0.55 */
                          /* 2.63 */   
#define KAPPA_RHO 3.71     
                          /* tensor to vector coupling constant for rho  */
                          /* 3.71 */ /* 6.1 */ 
#define G_RHONPIGA 0.131
                          /* coupling constant g_rho-pi-gamma */
                          /* 0.131 */
#define G_RHOCPIGA 0.103
                          /* coupling constant g_rho-pi-gamma */
                          /* 0.103 */


#define LAMBDA_PINN 13000.  
                           /* 1200. */
                           /* pion-nucleon-nucleon vertex cut-off */
#define LAMBDA_OMEGANN 2000. 
                           /* 2000. */  
                           /* omega-nucleon-nucleon vertex cut-off */
#define LAMBDA_PINDEL 2000.  /* 2000 */
                           /* cut-off at the crossed pi_nucleon-delta vertex */
#define LAMBDA_DEL 2000.  /* 2000 */
                           

#define F_PINDEL 1.949
                           /* coupling constant f_pindelta */
                           /* 1.949 unitarized background for
                                    charged pion channels */
                           /* 1.821 unitarized background for
                                    neutral pion channels */
                           

#define G_piNp33_off 0.0  /* 0.0 */     

#define G_GANDEL_M 2.75
                           /* magnetic coupling constant g_gandelta */
                           /* 3.10 nonrelativistic, nonunitarized background */
                           /* 2.75 relativistic, unitarized background */
                                       

/************************************************************************/
/*                                                                      */ 
/*                            P_11 (1440) RESONANCE                     */
/*                                                                      */ 
/************************************************************************/


#define M_p11 1463.         /* 1463. */ /* p11 resonance mass in MeV */

#define Width_p11 245.      /* 245. */

#define F_PINp11 0.374      /* 0.374 */     
#define G_piNp11_off 0.0    /* 0.0 */     



/************************************************************************/
/*                                                                      */ 
/*                            D_13 (1520) RESONANCE                     */
/*                                                                      */ 
/************************************************************************/


#define M_d13 1516.        /* 1516. */ /* d13 resonance mass in MeV */

#define Width_d13 106.      /* 106. */

#define F_PINd13 1.58      /* 1.58 */     
#define G_piNd13_off 0.0   /* 0.0 */     


/************************************************************************/
/*                                                                      */ 
/*                            S_11 (1535) RESONANCE                     */
/*                                                                      */ 
/************************************************************************/


#define M_s11 1525.         /* 1525. */ /* s11 resonance mass in MeV */

#define Width_s11 103.      /* 103. */

#define F_PINs11 0.11      /* 0.11 */     
#define G_piNs11_off 0.0    /* 0.0 */     



/************************************************************************/
/*                                                                      */ 
/*                            S_31 (1620) RESONANCE                     */
/*                                                                      */ 
/************************************************************************/


#define M_s31 1620.         /* 1620. */ /* s31 resonance mass in MeV */

#define Width_s31 147.      /* 147. */

#define F_PINs31 0.168      /* 0.168 */     
#define G_piNs31_off 0.0    /* 0.0 */     



/************************************************************************/
/*                                                                      */ 
/*                            D_33 (1700) RESONANCE                     */
/*                                                                      */ 
/************************************************************************/


#define M_d33 1690.        /* 1690. */ /* d33 resonance mass in MeV */

#define Width_d33 285.     /* 285. */

#define F_PINd33 1.36      /* 1.36 */     
#define G_piNd33_off 0.0   /* 0.0 */     



#endif