Decay/EvtGen/EvtGenDecayer.h

0001 // -*- C++ -*-
0002 #ifndef Herwig_EvtGenDecayer_H
0003 #define Herwig_EvtGenDecayer_H
0004 //
0005 // This is the declaration of the EvtGenDecayer class.
0006 //
0007
0008 #include "ThePEG/PDT/Decayer.h"
0009 #include "EvtGenInterface.h"
0010
0011 namespace Herwig {
0012
0013 using namespace ThePEG;
0014
0015 /**
0016  * The EvtGenDecayer class is designed to allow the EvtGen decay package to be used
0017  * as a Decayer in the Herwig structure.
0018  *
0019  * It is a simple wrapper which uses members of the Herwig EvtGen class to perform
0020  * the decay
0021  *
0022  * @see EvtGenInterface
0023  * @see \ref EvtGenDecayerInterfaces "The interfaces"
0024  * defined for EvtGenDecayer.
0025  */
0026 class EvtGenDecayer: public Decayer {
0027
0028 public:
0029
0030   /**
0031    * Standard constructors
0032    */
0033   EvtGenDecayer() : check_(0) , evtOpt_(0)
0034   {}
0035
0036 public:
0037
0038   /** @name Virtual functions required by the Decayer class. */
0039   //@{
0040   /**
0041    * Check if this decayer can perfom the decay specified by the
0042    * given decay mode.
0043    * @param dm the DecayMode describing the decay.
0044    * @return true if this decayer can handle the given mode, otherwise false.
0045    */
0046   virtual bool accept(const DecayMode & dm) const;
0047
0048   /**
0049    * Perform a decay for a given DecayMode and a given Particle instance.
0050    * @param dm the DecayMode describing the decay.
0051    * @param p the Particle instance to be decayed.
0052    * @return a ParticleVector containing the decay products.
0053    */
0054   virtual ParticleVector decay(const DecayMode & dm, const Particle & p) const;
0055   //@}
0056
0057 public:
0058
0059   /** @name Functions used by the persistent I/O system. */
0060   //@{
0061   /**
0062    * Function used to write out object persistently.
0063    * @param os the persistent output stream written to.
0064    */
0065   void persistentOutput(PersistentOStream & os) const;
0066
0067   /**
0068    * Function used to read in object persistently.
0069    * @param is the persistent input stream read from.
0070    * @param version the version number of the object when written.
0071    */
0072   void persistentInput(PersistentIStream & is, int version);
0073   //@}
0074
0075   /**
0076    * The standard Init function used to initialize the interfaces.
0077    * Called exactly once for each class by the class description system
0078    * before the main function starts or
0079    * when this class is dynamically loaded.
0080    */
0081   static void Init();
0082
0083 protected:
0084
0085   /**
0086    *  Method to check conservation of charge and momentum in the decay
0087    *  for testing only
0088    * @param parent The decaying particle
0089    */
0090   void checkDecay(PPtr parent) const;
0091
0092   /**
0093    *  Method to rescale the momenta of the decay products if required to
0094    *  conserve 4-momentum
0095    */
0096   bool rescale(const Particle & parent,
0097            const ParticleVector & children) const;
0098
0099 protected:
0100
0101   /** @name Clone Methods. */
0102   //@{
0103   /**
0104    * Make a simple clone of this object.
0105    * @return a pointer to the new object.
0106    */
0107   virtual IBPtr clone() const;
0108
0109   /** Make a clone of this object, possibly modifying the cloned object
0110    * to make it sane.
0111    * @return a pointer to the new object.
0112    */
0113   virtual IBPtr fullclone() const;
0114   //@}
0115
0116 private:
0117
0118   /**
0119    * The assignment operator is private and must never be called.
0120    * In fact, it should not even be implemented.
0121    */
0122   EvtGenDecayer & operator=(const EvtGenDecayer &) = delete;
0123
0124 private:
0125
0126   /**
0127    *  Pointer to the EvtGen interface object
0128    */
0129   EvtGenInterfacePtr evtgen_;
0130
0131   /**
0132    *  Perform checks ?
0133    */
0134   unsigned int check_;
0135
0136   /**
0137    *  Option for how EvtGen is used
0138    */
0139   unsigned int evtOpt_;
0140
0141 };
0142
0143 }
0144
0145 #endif /* Herwig_EvtGenDecayer_H */