Decay/General/StoSFFDecayer.h

0001 // -*- C++ -*-
0002 #ifndef THEPEG_StoSFFDecayer_H
0003 #define THEPEG_StoSFFDecayer_H
0004 //
0005 // This is the declaration of the StoSFFDecayer class.
0006 //
0007
0008 #include "GeneralThreeBodyDecayer.h"
0009 #include "ThePEG/Helicity/Vertex/AbstractSSSVertex.h"
0010 #include "ThePEG/Helicity/Vertex/AbstractFFSVertex.h"
0011 #include "ThePEG/Helicity/Vertex/AbstractRFSVertex.h"
0012 #include "ThePEG/Helicity/Vertex/AbstractVSSVertex.h"
0013 #include "ThePEG/Helicity/Vertex/AbstractFFVVertex.h"
0014 #include "ThePEG/Helicity/Vertex/AbstractSSTVertex.h"
0015 #include "ThePEG/Helicity/Vertex/AbstractFFTVertex.h"
0016 #include "ThePEG/Helicity/Vertex/AbstractFFSSVertex.h"
0017
0018 namespace Herwig {
0019   using namespace ThePEG;
0020
0021 /**
0022  * The StoSFFDecayer class provides the general matrix element for
0023  * scalar decays into another scalar and a fermion-antifermion pair.
0024  *
0025  * @see \ref StoSFFDecayerInterfaces "The interfaces"
0026  * defined for StoSFFDecayer.
0027  */
0028 class StoSFFDecayer: public GeneralThreeBodyDecayer {
0029
0030 public:
0031
0032   /**
0033    * Return the matrix element squared for a given mode and phase-space channel.
0034    * @param ichan The channel we are calculating the matrix element for.
0035    * @param part The decaying Particle.
0036    * @param outgoing The particles produced in the decay
0037    * @param momenta  The momenta of the particles produced in the decay
0038    * @param meopt Option for the calculation of the matrix element
0039    * @return The matrix element squared for the phase-space configuration.
0040    */
0041   double me2(const int ichan,const Particle & part,
0042          const tPDVector & outgoing,
0043          const vector<Lorentz5Momentum> & momenta,
0044          MEOption meopt) const;
0045
0046   /**
0047    *   Construct the SpinInfos for the particles produced in the decay
0048    */
0049   virtual void constructSpinInfo(const Particle & part,
0050                  ParticleVector outgoing) const;
0051
0052   /**
0053    * Method to return an object to calculate the 3 (or higher body) partial width
0054    * @param dm The DecayMode
0055    * @return A pointer to a WidthCalculatorBase object capable of calculating the width
0056    */
0057   virtual WidthCalculatorBasePtr threeBodyMEIntegrator(const DecayMode & dm) const;
0058
0059 public:
0060
0061   /** @name Functions used by the persistent I/O system. */
0062   //@{
0063   /**
0064    * Function used to write out object persistently.
0065    * @param os the persistent output stream written to.
0066    */
0067   void persistentOutput(PersistentOStream & os) const;
0068
0069   /**
0070    * Function used to read in object persistently.
0071    * @param is the persistent input stream read from.
0072    * @param version the version number of the object when written.
0073    */
0074   void persistentInput(PersistentIStream & is, int version);
0075   //@}
0076
0077   /**
0078    * The standard Init function used to initialize the interfaces.
0079    * Called exactly once for each class by the class description system
0080    * before the main function starts or
0081    * when this class is dynamically loaded.
0082    */
0083   static void Init();
0084
0085 protected:
0086
0087   /** @name Clone Methods. */
0088   //@{
0089   /**
0090    * Make a simple clone of this object.
0091    * @return a pointer to the new object.
0092    */
0093   virtual IBPtr clone() const;
0094
0095   /** Make a clone of this object, possibly modifying the cloned object
0096    * to make it sane.
0097    * @return a pointer to the new object.
0098    */
0099   virtual IBPtr fullclone() const;
0100   //@}
0101
0102 protected:
0103
0104   /**
0105    *   Set up the diagrams etc
0106    */
0107   virtual void setupDiagrams(bool checkKinematics);
0108
0109 private:
0110
0111   /**
0112    * The assignment operator is private and must never be called.
0113    * In fact, it should not even be implemented.
0114    */
0115   StoSFFDecayer & operator=(const StoSFFDecayer &) = delete;
0116
0117 private:
0118
0119   /**
0120    * Store the vertices for scalar intermediate
0121    */
0122   vector<pair<AbstractSSSVertexPtr, AbstractFFSVertexPtr> > sca_;
0123
0124   /**
0125    * Store the vertices for spin-\f$\frac12\f$ fermion intermediate
0126    */
0127   vector<pair<AbstractFFSVertexPtr, AbstractFFSVertexPtr> > fer_;
0128
0129   /**
0130    * Store the vertices for spin-\f$\frac32\f$  fermion intermediate
0131    */
0132   vector<pair<AbstractRFSVertexPtr, AbstractRFSVertexPtr> > RSfer_;
0133
0134   /**
0135    * Store the vertices for vector intermediate
0136    */
0137   vector<pair<AbstractVSSVertexPtr, AbstractFFVVertexPtr> > vec_;
0138
0139   /**
0140    * Store the vertices for tensor intermediate
0141    */
0142   vector<pair<AbstractSSTVertexPtr, AbstractFFTVertexPtr> > ten_;
0143
0144   /**
0145    * Store the vertices for four point diagrams
0146    */
0147   vector<AbstractFFSSVertexPtr> four_;
0148
0149   /**
0150    *  Spin density matrix
0151    */
0152   mutable RhoDMatrix rho_;
0153
0154   /**
0155    *  Scalar wavefunction
0156    */
0157   mutable ScalarWaveFunction swave_;
0158
0159   /**
0160    *  Spinor wavefunctions
0161    */
0162   mutable pair<vector<SpinorWaveFunction>,vector<SpinorBarWaveFunction> > outspin_[3];
0163 };
0164
0165 }
0166
0167 #endif /* THEPEG_StoSFFDecayer_H */