Decay/VectorMeson/f1RhoPiPiDecayer.h

0001 // -*- C++ -*-
0002 #ifndef Herwig_f1RhoPiPiDecayer_H
0003 #define Herwig_f1RhoPiPiDecayer_H
0004 //
0005 // This is the declaration of the f1RhoPiPiDecayer class.
0006 //
0007
0008 #include "DecayIntegrator.h"
0009
0010 namespace Herwig {
0011
0012 using namespace ThePEG;
0013
0014 /**
0015  * Here is the documentation of the f1RhoPiPiDecayer class.
0016  *
0017  * @see \ref f1RhoPiPiDecayerInterfaces "The interfaces"
0018  * defined for f1RhoPiPiDecayer.
0019  */
0020 class f1RhoPiPiDecayer: public DecayIntegrator {
0021
0022 public:
0023
0024   /**
0025    * The default constructor.
0026    */
0027   f1RhoPiPiDecayer();
0028
0029   /**
0030    * Which of the possible decays is required
0031    * @param cc Is this mode the charge conjugate
0032    * @param parent The decaying particle
0033    * @param children The decay products
0034    */
0035   virtual int modeNumber(bool & cc, tcPDPtr parent,
0036              const tPDVector & children) const;
0037
0038   /**
0039    * Return the matrix element squared for a given mode and phase-space channel.
0040    * @param ichan The channel we are calculating the matrix element for.
0041    * @param part The decaying Particle.
0042    * @param outgoing The particles produced in the decay
0043    * @param momenta  The momenta of the particles produced in the decay
0044    * @param meopt Option for the calculation of the matrix element
0045    * @return The matrix element squared for the phase-space configuration.
0046    */
0047   double me2(const int ichan,const Particle & part,
0048          const tPDVector & outgoing,
0049          const vector<Lorentz5Momentum> & momenta,
0050          MEOption meopt) const;
0051
0052   /**
0053    *   Construct the SpinInfos for the particles produced in the decay
0054    */
0055   virtual void constructSpinInfo(const Particle & part,
0056                  ParticleVector outgoing) const;
0057
0058   /**
0059    * Output the setup information for the particle database
0060    * @param os The stream to output the information to
0061    * @param header Whether or not to output the information for MySQL
0062    */
0063   virtual void dataBaseOutput(ofstream & os,bool header) const;
0064
0065   /**
0066    * For a given decay mode and a given particle instance, perform the
0067    * decay and return the decay products. As this is the base class this
0068    * is not implemented.
0069    * @return The vector of particles produced in the decay.
0070    */
0071   virtual ParticleVector decay(const Particle & parent,
0072                    const tPDVector & children) const;
0073 public:
0074
0075   /** @name Functions used by the persistent I/O system. */
0076   //@{
0077   /**
0078    * Function used to write out object persistently.
0079    * @param os the persistent output stream written to.
0080    */
0081   void persistentOutput(PersistentOStream & os) const;
0082
0083   /**
0084    * Function used to read in object persistently.
0085    * @param is the persistent input stream read from.
0086    * @param version the version number of the object when written.
0087    */
0088   void persistentInput(PersistentIStream & is, int version);
0089   //@}
0090
0091   /**
0092    * The standard Init function used to initialize the interfaces.
0093    * Called exactly once for each class by the class description system
0094    * before the main function starts or
0095    * when this class is dynamically loaded.
0096    */
0097   static void Init();
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 protected:
0117
0118   /** @name Standard Interfaced functions. */
0119   //@{
0120   /**
0121    * Initialize this object after the setup phase before saving an
0122    * EventGenerator to disk.
0123    * @throws InitException if object could not be initialized properly.
0124    */
0125   virtual void doinit();
0126
0127   /**
0128    * Initialize this object. Called in the run phase just before
0129    * a run begins.
0130    */
0131   virtual void doinitrun();
0132   //@}
0133
0134 private:
0135
0136   /**
0137    * The assignment operator is private and must never be called.
0138    * In fact, it should not even be implemented.
0139    */
0140   f1RhoPiPiDecayer & operator=(const f1RhoPiPiDecayer &) = delete;
0141
0142 private:
0143
0144   /**
0145    *  a_1-rho-pi
0146    */
0147   Energy ga1RhoPi_;
0148
0149   /**
0150    *  f1-a1-pi
0151    */
0152   InvEnergy gf1a1Pi_;
0153
0154   /**
0155    *  a1 mass
0156    */
0157   Energy ma1_;
0158
0159   /**
0160    * a1 width
0161    */
0162   Energy ga1_;
0163
0164
0165   /**
0166    *  Weights for the different decay modes
0167    */
0168   vector<double> maxWeight_;
0169
0170   /**
0171    *  Spin Density matrix
0172    */
0173   mutable RhoDMatrix rho_;
0174
0175   /**
0176    *  Polarization vectors
0177    */
0178   mutable vector<Helicity::LorentzPolarizationVector> vectors_[2];
0179
0180 };
0181
0182 }
0183
0184 #endif /* Herwig_f1RhoPiPiDecayer_H */