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 // -*- C++ -*-
 #ifndef HELICITY_GeneralVVSVertex_H
 #define HELICITY_GeneralVVSVertex_H
 //
 // This is the declaration of the GeneralVVSVertex class.
 //
 
 #include "ThePEG/Helicity/Vertex/AbstractVVSVertex.h"
 #include "ThePEG/Helicity/WaveFunction/ScalarWaveFunction.h"
 #include "ThePEG/Helicity/WaveFunction/VectorWaveFunction.h"
 #include "GeneralVVSVertex.fh"
 
 namespace ThePEG {
 namespace Helicity {
 
 using namespace ThePEG;
 
 /**
  * The GeneralVVSVertex class implements a
  * general Vector-Vector-Scalar vertex allowing for decay modes 
  * that only enter at the one-loop level
  * 
  * The loop integral is calculated by Passarino-Veltman reduction 
  * and the coefficients are stored here. They must be calculated
  * in the inheriting class along with implementation of the
  * setCoupling member.
  *
  *  The vertex takes the form
  *  \f[  a_{00}g^{\mu\nu}p_1\cdot p_2 + a_{11}p_1^\mu p_1^\nu
  *     + a_{12}p_1^\mu p_2^\nu + a_{21}p_2^\mu p_1^\nu
  *     + a_{22}p_2^\mu p_2^\nu +a_e\epsilon^{p_1 \mu \nu p_2}\f]
  *
  */
 class GeneralVVSVertex: public AbstractVVSVertex {
 
 public:
 
   /**
    * The default constructor.
    */
   GeneralVVSVertex() : _a00(1), 
                _a11(0), _a12(0), 
                _a21(0), _a22(0),
                _aEp(0)
   {}
 
   /**
    * The standard Init function used to initialize the interfaces.
    * Called exactly once for each class by the class description system
    * before the main function starts or
    * when this class is dynamically loaded.
    */
   static void Init();
 
 public:
   
   /**
    * Members to calculate the helicity amplitude expressions for vertices
    * and off-shell particles.
    */
   //@{
   /**
    * Evaluate the vertex.
    * @param q2 The scale \f$q^2\f$ for the coupling at the vertex.
    * @param vec1 The wavefunction for the first  vector.
    * @param vec2 The wavefunction for the second vector.
    * @param sca3 The wavefunction for the scalar.
    */
   virtual Complex evaluate(Energy2 q2,const VectorWaveFunction & vec1,
                const VectorWaveFunction & vec2,
                const ScalarWaveFunction & sca3);
 
   /**
    * Evaluate the off-shell vector coming from the vertex.
    * @param q2 The scale \f$q^2\f$ for the coupling at the vertex.
    * @param iopt Option of the shape of the Breit-Wigner for the off-shell vector.
    * @param out The ParticleData pointer for the off-shell vector.
    * @param vec2 The wavefunction for the vector.
    * @param sca3 The wavefunction for the scalar.
    * @param mass The mass of the off-shell particle if not taken from the ParticleData
    * object
    * @param width The width of the off-shell particle if not taken from the ParticleData
    * object
    */
   virtual VectorWaveFunction evaluate(Energy2 q2,int iopt,tcPDPtr out,
                       const VectorWaveFunction & vec2,
                       const ScalarWaveFunction & sca3,
                       complex<Energy> mass=-GeV, complex<Energy> width=-GeV);
 
   /**
    * Evaluate the off-shell scalar coming from the vertex.
    * @param q2 The scale \f$q^2\f$ for the coupling at the vertex.
    * @param iopt Option of the shape of the Breit-Wigner for the off-shell scalar.
    * @param out The ParticleData pointer for the off-shell scalar.
    * @param vec1 The wavefunction for the first  vector.
    * @param vec2 The wavefunction for the second vector.
    * @param mass The mass of the off-shell particle if not taken from the ParticleData
    * object
    * @param width The width of the off-shell particle if not taken from the ParticleData
    * object
    */
   virtual ScalarWaveFunction evaluate(Energy2 q2,int iopt, tcPDPtr out,
                       const VectorWaveFunction & vec1,
                       const VectorWaveFunction & vec2,
                       complex<Energy> mass=-GeV, complex<Energy> width=-GeV);
   //@}
 
   /**
    *   Set coupling methods
    */
   //@{
   /**
    * Calculate the couplings for a three point interaction.
    * This method is virtual and must be implemented in 
    * classes inheriting from this.
    * @param q2 The scale \f$q^2\f$ for the coupling at the vertex.
    * @param part1 The ParticleData pointer for the first  particle.
    * @param part2 The ParticleData pointer for the second particle.
    * @param part3 The ParticleData pointer for the third  particle.
    */
   virtual void setCoupling(Energy2 q2,tcPDPtr part1,
                tcPDPtr part2,tcPDPtr part3)=0;
 
   /**
    * Dummy setCouplings for a four point interaction 
    * This method is virtual and must be implemented in 
    * classes inheriting from this.
    */
   virtual void setCoupling(Energy2,tcPDPtr,tcPDPtr,tcPDPtr,tcPDPtr) {
     assert(false);
   }
   //@}
 
 public:
 
   /**@name Set and Get tensor coefficients.*/
   //@{
   /**
    * Access coefficient of \f$g^{\mu\nu}\f$
    */
   Complex a00() const {return _a00;}
       
   /**
    * Access coefficient of \f$p_1^\mu p_1^\nu\f$
    */
   Complex a11() const {return _a11;}
       
   /**
    * Access coefficient of \f$p_1^\mu p_2^\nu\f$
    */
   Complex a12() const {return _a12;}
       
   /**
    * Access coefficient of \f$p_2^\mu p_1^\nu\f$
    */
   Complex a21() const {return _a21;}
       
   /**
    * Access coefficient of \f$p_2^\mu p_2^\nu\f$
    */
   Complex a22() const {return _a22;}
       
   /**
    * Access coefficient of \f$\epsilon^{\mu\nu\alpha\beta}p_1\alpha p_2\beta\f$
    */
   Complex aEp() const {return _aEp;}
       
   /**
    * Set tensor coefficient of \f$g^{\mu\nu}\f$
    */
   void a00(const Complex & val) {_a00 = val;}
       
   /**
    * Set tensor coefficient of \f$p_1^\mu p_1^\nu\f$
    */
   void a11(const Complex & val) {_a11 = val;}
       
   /**
    * Set tensor coefficient of \f$p_1^\mu p_2^\nu\f$
    */
   void a12(const Complex & val) {_a12 = val;}
       
   /**
    * Set tensor coefficient of \f$p_2^\mu p_1^\nu\f$
    */
   void a21(const Complex & val) {_a21 = val;}
       
   /**
    * Set tensor coefficient of \f$p_2^\mu p_2^\nu\f$
    */ 
   void a22(const Complex & val) {_a22 = val;}
       
   /**
    * Set tensor coefficient of \f$\epsilon^{\mu\nu\alpha\beta}p_1\alpha p_2\beta\f$
    */
   void aEp(const Complex & val) {_aEp = val;}
   //@}
 
 private:
 
   /**
    * The assignment operator is private and must never be called.
    * In fact, it should not even be implemented.
    */
   GeneralVVSVertex & operator=(const GeneralVVSVertex &) = delete;
 
       
 private:
   
   /** @name Store tensor coefficients.*/
   //@{
   /**
    * Coefficient of \f$g^{\mu\nu}\f$
    */
   Complex _a00;
 
   /**
    * Coefficient of \f$p_1^\mu p_1^\nu\f$
    */
   Complex _a11;
 
   /**
    * Coefficient of \f$p_1^\mu p_2^\nu\f$
    */
   Complex _a12;
 
   /**
    * Coefficient of \f$p_2^\mu p_1^\nu\f$
    */
   Complex _a21;
 
   /**
    * Coefficient of \f$p_2^\mu p_2^\nu\f$
    */
   Complex _a22;
 
   /**
    * Coefficient of \f$\epsilon^{\mu\nu\alpha\beta}p_1\alpha p_2\beta\f$
    */
   Complex _aEp;
   //@}
 };
 
 }
 }
 #endif /* HELICITY_GeneralVVSVertex_H */

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