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 // -*- C++ -*-
 #ifndef HERWIG_BaryonFormFactor_H
 #define HERWIG_BaryonFormFactor_H
 //
 // This is the declaration of the BaryonFormFactor class.
 //
 #include "ThePEG/Interface/Interfaced.h"
 #include "BaryonFormFactor.fh"
 #include "ThePEG/Config/Complex.h"
 #include "Herwig/Decay/IsoSpin.h"
 
 namespace Herwig {
 using namespace ThePEG;
 
   /** \ingroup Decay
    * The BaryonFormFactor class is the base class for the implementation
    * of the form-factors for the weak decay of a baryon. 
    *
    *  This is designed so that the form factors can be used for both the semi-leptonic
    *  decays and using factorization for hadronic weak decays.
    *
    *  The form factors are given below for the decay \f$X(p_0)\to Y(p_1)\f$ with 
    *  \f$q_\mu=(p_0-p_1)_\mu\f$.
    *
    *
    *  The form-factors are defined to be 
    *
    *   \f[\bar{u}(p_1) \left[  \gamma^\mu \left(F^V_1+F^A_1 \gamma_5\right)
    *  +\frac{i}{(m_0+m_1)}\sigma_{\mu\nu}q^\nu\left(F^V_2+F^A_2\gamma_5\right)
    *  +\frac1{(m_0+m_1)}q^\mu\left(F^V_3+F^A_3\gamma_5\right)\right] u(p_0) \f]
    *
    *   for the \f$\frac12\to\frac12\f$ transition and
    *
    *  \f[\bar{u}^\alpha(p_1) \left[ g_{\alpha\mu}\left(G^V_1+G^A_1 \gamma_5\right)
    *   +\frac1{(m_0+m_1)}p_{0\alpha}\gamma_\mu\left(G^V_2+G^A_2\gamma_5\right)
    *   +\frac1{(m_0+m_1)^2}p_{0\alpha}p_{1\mu}\left(G^V_3+G^A_3\gamma_5\right)\right.\f]
    * \f[ \left.
    *   +\frac1{(m_0+m_1)^2}p_{0\alpha}q_\mu\left(G^V_4+G^A_4\gamma_5\right)\right]
    * \gamma_5 u(p_0) 
    * \f]
    *   for the \f$\frac12\to\frac32\f$ transition.
    *
    *  These definitions differ from those in the liturature because we have divided some
    *  terms by the sum of the baryon masses to ensure that the form-factors are all
    *  dimensionless.
    *
    *  In many applications, particularly for the decay of baryons containing a heavy
    *  quark, an alternative version of the form factors in terms of the velocities
    *  of the baryons is used. This form is
    *
    *   \f[\bar{u}(v') \left[  \gamma^\mu \left(F_1-G_1 \gamma_5\right)
    *                               v^\mu \left(F_2-G_2 \gamma_5\right)
    *                            {v'}^\mu \left(F_3-G_3\gamma_5\right)\right] u(v) \f]
    *
    *   for the \f$\frac12\to\frac12\f$ transition and
    *
    *  \f[\bar{u}^\alpha(v') \left[ v_\alpha\gamma_\mu\left(N_1-K_1 \gamma_5\right)
    *                              +v_\alpha v^\mu    \left(N_2-K_2 \gamma_5\right)
    *                              +v_\alpha {v'}^\mu \left(N_3-K_3 \gamma_5\right)
    *                              +g_\alpha^\mu      \left(N_4-K_4 \gamma_5\right)\right]
    * \gamma_5 u(v) 
    * \f]
    *   for the \f$\frac12\to\frac32\f$ transition.
    *
    *  In terms of these form factors the form factors we use are
    *
    * \f[F^V_1= F_1+\frac12(m_0+m_1)\left(\frac{F_2}{m_0}+\frac{F_3}{m_1}\right)\f]
    * \f[F^V_2=\frac12(m_0+m_1)\left(\frac{F_2}{m_0}+\frac{F_3}{m_1}\right)\f]
    * \f[F^V_3=\frac12(m_0+m_1)\left(\frac{F_2}{m_0}-\frac{F_3}{m_1}\right)\f]
    * \f[F^A_1=-G_1+\frac12(m_0-m_1)\left(\frac{G_2}{m_0}+\frac{G_3}{m_1}\right)\f]
    * \f[F^A_2=-\frac12(m_0+m_1)\left(\frac{G_2}{m_0}+\frac{G_3}{m_1}\right)\f]
    * \f[F^A_3=\frac12(m_0+m_1)\left(-\frac{G_2}{m_0}+\frac{G_3}{m_1}\right)\f]
    *
    *   for the \f$\frac12\to\frac12\f$ transition and
    *
    * \f[G_1^V = N_4\f]
    * \f[G_2^V = N_1\frac{(m_0+m_1)}{m_0}\f]
    * \f[G_3^V = \frac{(m_0+m_1)^2}{m_0}\left(\frac{N_2}{m_0}+\frac{N_3}{m_1}\right)\f]
    * \f[G_4^V = N_2\frac{(m_0+m_1)^2}{m^2_0}\f]
    * \f[G_1^A =-K_4\f]
    * \f[G_2^A =-K_1\frac{(m_0+m_1)}{m_0}\f]
    * \f[G_3^A =-\frac{(m_0+m_1)^2}{m_0}\left(\frac{K_2}{m_0}+\frac{K_3}{m_1}\right)\f]
    * \f[G_4^A =-K_2\frac{(m_0+m_1)^2}{m^2_0}\f]
    *
    *   for the \f$\frac12\to\frac32\f$ transition.
    *
    * 
    * @see ScalarFormFactor
    * 
    */
 
 class BaryonFormFactor: public Interfaced {
 
 public:
 
   /**
    *   Whether the form factor is space- or time-like
    */
   enum Virtuality {TimeLike, SpaceLike};
 
   
 public:
 
   /**
    * Default constructor
    */
   BaryonFormFactor() : _numbermodes() {}
 
   /** @name Functions used by the persistent I/O system. */
   //@{
   /**
    * Function used to write out object persistently.
    * @param os the persistent output stream written to.
    */
   void persistentOutput(PersistentOStream & os) const;
 
   /**
    * Function used to read in object persistently.
    * @param is the persistent input stream read from.
    * @param version the version number of the object when written.
    */
   void persistentInput(PersistentIStream & is, int version);
   //@}
 
   /**
    * Standard Init function used to initialize the interfaces.
    */
   static void Init();
 
 protected:
 
   /** @name Clone Methods. */
   //@{
   /**
    * Make a simple clone of this object.
    * @return a pointer to the new object.
    */
   virtual IBPtr clone() const {return new_ptr(*this);}
 
   /** Make a clone of this object, possibly modifying the cloned object
    * to make it sane.
    * @return a pointer to the new object.
    */
   virtual IBPtr fullclone() const {return new_ptr(*this);}
   //@}
 
 public:
 
   /** @name Functions to give information about the form factors available. */
   //@{
 
   /**
    * Find the location for a given pair of particle. 
    * \param in   PDG code for the incoming baryon.
    * \param out  PDG code for the outgoing baryon.
    * \param cc  particles or charge conjugates stored in form factor.
    * @return The location in the vectors storing the data. 
    */
   int formFactorNumber(int in,int out,bool & cc) const {
     int output(-1);
     unsigned int ix(0);
     if(_incomingid.size()==0){return output;}
     do {
       if(_incomingid[ix]== in && _outgoingid[ix]== out) {
     cc=false;
     output=ix;
       }
       else if (_incomingid[ix]==-in && _outgoingid[ix]==-out) {
     cc=true;
     output=ix;
       }
       ++ix;
     }
     while(ix<_incomingid.size()&&output<0);
     return output;
   }
 
   /**
    * Get the particle ids for an entry.
    * @param iloc The location in the list.
    * @param id0 The PDG code for the incoming baryon.
    * @param id1 The PDG code for the outgoing baryon.
    */
   void particleID(int iloc,int& id0,int& id1) {
     id0=_incomingid[iloc];
     id1=_outgoingid[iloc];
   }
 
   /**
    * Information on the form factor.
    * @param iloc The location in the list.
    * @param ispin The spin of the incoming baryon.
    * @param ospin The spin of the outgoing baryon.
    * @param spect1 The PDG code of the first spectator quark.
    * @param spect2 The PDG code of the second spectator quark.
    * @param inquark The PDG code for decaying incoming quark.
    * @param outquark The PDG code for the outgoing quark produced in the decay.
    */
   void formFactorInfo(int iloc,int & ispin,int & ospin,int & spect1,
               int & spect2, int & inquark,int & outquark) {
     ispin    = _incomingJ[iloc];
     ospin    = _outgoingJ[iloc];
     spect1   = _spectator1[iloc];
     spect2   = _spectator2[iloc];
     inquark  = _inquark[iloc];
     outquark = _outquark[iloc]; 
   }
 
   /**
    * Information on the form factor.
    * @param in The PDG code of the incoming baryon.
    * @param out The PDG code of the outgoing baryon.
    * @param ispin The spin of the incoming baryon.
    * @param ospin The spin of the outgoing baryon.
    * @param spect1 The PDG code of the first spectator quark.
    * @param spect2 The PDG code of the second spectator quark.
    * @param inquark The PDG code for decaying incoming quark.
    * @param outquark The PDG code for the outgoing quark produced in the decay.
    */
   void formFactorInfo(int in,int out,int & ispin,int & ospin,int & spect1,
               int & spect2, int & inquark,int & outquark) {
     bool dummy;
     unsigned int ix=formFactorNumber(in,out,dummy);
     formFactorInfo(ix,ispin,ospin,spect1,spect2,inquark,outquark);
   }
 
   /**
    * number of form factors
    */
   unsigned int numberOfFactors() const {return _incomingid.size();}
   //@}
 
 public:
 
   /** @name Form Factors */
   //@{
   /**
    * The form factor for the weak decay of a spin \f$\frac12\f$ baryon to a 
    * spin \f$\frac12\f$ baryon.  
    * This method is virtual and must be implementented in classes
    * inheriting from this which include spin\f$\frac12\f$  to spin \f$\frac12\f$
    * form factors.
    * @param q2 The scale \f$q^2\f$.
    * @param iloc The location in the form factor list.
    * @param id0 The PDG code of the incoming baryon.
    * @param id1 The PDG code of the outgoing baryon.
    * @param m0 The mass of the incoming baryon.
    * @param m1 The mass of the outgoing baryon.
    * @param f1v The form factor \f$F^V_1\f$.
    * @param f2v The form factor \f$F^V_2\f$.
    * @param f3v The form factor \f$F^V_3\f$.
    * @param f1a The form factor \f$F^A_1\f$.
    * @param f2a The form factor \f$F^A_2\f$.
    * @param f3a The form factor \f$F^A_3\f$.
    * @param virt Whether the q2 is space or timelike
    */
   virtual void SpinHalfSpinHalfFormFactor(Energy2 q2,int iloc, int id0, int id1,
                       Energy m0, Energy m1,
                       Complex & f1v,Complex & f2v,Complex & f3v,
                       Complex & f1a,Complex & f2a,Complex & f3a,
                       FlavourInfo flavour,
                       Virtuality virt=SpaceLike);
 
   /**
    * The form factor for the weak decay of a spin \f$\frac12\f$ baryon to a 
    * spin \f$\frac32\f$ baryon.  
    * This method is virtual and must be implementented in classes
    * inheriting from this which include spin\f$\frac12\f$  to spin \f$\frac32\f$
    * form factors.
    * @param q2 The scale \f$q^2\f$.
    * @param iloc The location in the form factor list.
    * @param id0 The PDG code of the incoming baryon.
    * @param id1 The PDG code of the outgoing baryon.
    * @param m0 The mass of the incoming baryon.
    * @param m1 The mass of the outgoing baryon.
    * @param g1v The form factor \f$G^V_1\f$.
    * @param g2v The form factor \f$G^V_2\f$.
    * @param g3v The form factor \f$G^V_3\f$.
    * @param g4v The form factor \f$G^V_4\f$.
    * @param g1a The form factor \f$G^A_1\f$.
    * @param g2a The form factor \f$G^A_2\f$.
    * @param g3a The form factor \f$G^A_3\f$.
    * @param g4a The form factor \f$G^A_4\f$.
    * @param virt Whether the q2 is space or timelike
    */
   virtual void SpinHalfSpinThreeHalfFormFactor(Energy2 q2,int iloc, int id0, int id1,
                            Energy m0, Energy m1,
                            Complex & g1v,Complex & g2v,Complex & g3v,
                            Complex & g4v,Complex & g1a,Complex & g2a,
                            Complex & g3a,Complex & g4a,
                            FlavourInfo flavour,
                            Virtuality virt=SpaceLike);
   //@}
 
   /**
    * Output the setup information for the particle database
    * @param os The stream to output the information to
    * @param header Whether or not to output the information for MySQL
    * @param create Whether or not to add a statement creating the object
    */
   virtual void dataBaseOutput(ofstream & os,bool header,bool create) const;
 
 protected:  
 
   /**
    * Add a form factor to the list.
    * @param in The PDG code of the incoming baryon.
    * @param out The PDG code of the outgoing baryon.
    * @param inspin The spin of the incoming baryon.
    * @param outspin The spin of the outgoing baryon.
    * @param spect1 The PDG code of the first  spectator quark.
    * @param spect2 The PDG code of the second spectator quark.
    * @param inquark The PDG code for decaying incoming quark.
    * @param outquark The PDG code for the outgoing quark produced in the decay.
    */
   void addFormFactor(int in,int out,int inspin, int outspin, int spect1,
              int spect2, int inquark,int outquark) {
     _incomingid.push_back(in);
     _outgoingid.push_back(out);
     _incomingJ.push_back(inspin);
     _outgoingJ.push_back(outspin);
     _spectator1.push_back(spect1);
     _spectator2.push_back(spect2);
     _inquark.push_back(inquark);
     _outquark.push_back(outquark);
   }
 
   /**
    *  Set initial number of modes
    * @param nmodes The number of modes.
    */
   void initialModes(unsigned int nmodes) {_numbermodes=nmodes;}
 
   /**
    * Get the initial number of modes
    */
   unsigned int initialModes() const {return _numbermodes;}
 
 protected:
 
   /** @name Standard Interfaced functions. */
   //@{
   /**
    * Initialize this object after the setup phase before saving and
    * EventGenerator to disk.
    * @throws InitException if object could not be initialized properly.
    */
   virtual void doinit();
   //@}
 
 private:
 
   /**
    * Private and non-existent assignment operator.
    */
   BaryonFormFactor & operator=(const BaryonFormFactor &) = delete;
 
   private:
 
   /**
    * the id's of the incoming particles
    */
   vector<int> _incomingid;
 
   /**
    * the id's of the  outgoing particles
    */
   vector<int> _outgoingid;
 
   /**
    * spin of the incoming particle
    */
   vector<int> _incomingJ;
 
   /**
    * spin of the outgoing particle
    */
   vector<int> _outgoingJ;
 
   /**
    * the id of the first spectator quark
    */
   vector<int> _spectator1;
 
   /**
    * the id of the second spectator quark
    */
   vector<int> _spectator2;
 
   /**
    * the id of the decaying quark
    */
   vector<int> _inquark;
 
   /**
    * the id of the outgoing quark
    */
   vector<int> _outquark;
 
   /**
    * The initial number of modes
    */
   unsigned int _numbermodes;
 };
 
 }
 
 #endif /* HERWIG_BaryonFormFactor_H */

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