Matchbox/Dipoles/FFMggxDipole.h

0001 // -*- C++ -*-
0002 //
0003 // FFMggxDipole.h is a part of Herwig - A multi-purpose Monte Carlo event generator
0004 // Copyright (C) 2002-2019 The Herwig Collaboration
0005 //
0006 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
0007 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
0008 //
0009 #ifndef HERWIG_FFMggxDipole_H
0010 #define HERWIG_FFMggxDipole_H
0011 //
0012 // This is the declaration of the FFMggxDipole class.
0013 //
0014
0015 #include "Herwig/MatrixElement/Matchbox/Dipoles/SubtractionDipole.h"
0016
0017 namespace Herwig {
0018
0019 using namespace ThePEG;
0020
0021 /**
0022  * \ingroup Matchbox
0023  * \author Simon Platzer, Martin Stoll
0024  *
0025  * \brief FFMggxDipole implements the D_{g,g;k} subtraction dipole.
0026  *
0027  */
0028 class FFMggxDipole: public SubtractionDipole {
0029
0030 public:
0031
0032   /**
0033    * The default constructor.
0034    */
0035   FFMggxDipole();
0036
0037 public:
0038
0039   /**
0040    * Return true, if this dipole can possibly handle the indicated
0041    * emitter.
0042    */
0043   virtual bool canHandleEmitter(const cPDVector& partons, int emitter) const {
0044     return emitter > 1 && partons[emitter]->id() == ParticleID::g;
0045   }
0046
0047   /**
0048    * Return true, if this dipole can possibly handle the indicated
0049    * splitting.
0050    */
0051   virtual bool canHandleSplitting(const cPDVector& partons, int emitter, int emission) const {
0052     return canHandleEmitter(partons,emitter) && partons[emission]->id() == ParticleID::g;
0053   }
0054
0055   /**
0056    * Return true, if this dipole can possibly handle the indicated
0057    * spectator.
0058    */
0059   virtual bool canHandleSpectator(const cPDVector& partons, int spectator) const {
0060     return spectator > 1 && partons[spectator]->coloured();
0061   }
0062
0063   /**
0064    * Return true, if this dipole applies to the selected
0065    * configuration.
0066    */
0067   virtual bool canHandle(const cPDVector& partons,
0068              int emitter, int emission, int spectator) const;
0069
0070   /**
0071    * Return true, if this dipole is symmetric with respect to emitter
0072    * and emission.
0073    */
0074   virtual bool isSymmetric() const { return true; }
0075
0076   /**
0077    *  How to sample the z-distribution.
0078    *  FlatZ = 1
0079    *  OneOverZ = 2
0080    *  OneOverOneMinusZ = 3
0081    *  OneOverZOneMinusZ = 4
0082    */
0083
0084   virtual int samplingZ() const {return 4;}
0085
0086   /**
0087    * Return the matrix element for the kinematical configuation
0088    * previously provided by the last call to setKinematics(), suitably
0089    * scaled by sHat() to give a dimension-less number.
0090    */
0091   virtual double me2() const;
0092
0093   /**
0094    * Return the matrix element averaged over spin correlations.
0095    */
0096   virtual double me2Avg(double ccme2) const;
0097
0098 public:
0099
0100   /** @name Functions used by the persistent I/O system. */
0101   //@{
0102   /**
0103    * Function used to write out object persistently.
0104    * @param os the persistent output stream written to.
0105    */
0106   void persistentOutput(PersistentOStream & os) const;
0107
0108   /**
0109    * Function used to read in object persistently.
0110    * @param is the persistent input stream read from.
0111    * @param version the version number of the object when written.
0112    */
0113   void persistentInput(PersistentIStream & is, int version);
0114   //@}
0115
0116   /**
0117    * The standard Init function used to initialize the interfaces.
0118    * Called exactly once for each class by the class description system
0119    * before the main function starts or
0120    * when this class is dynamically loaded.
0121    */
0122   static void Init();
0123
0124 protected:
0125
0126   /** @name Clone Methods. */
0127   //@{
0128   /**
0129    * Make a simple clone of this object.
0130    * @return a pointer to the new object.
0131    */
0132   virtual IBPtr clone() const;
0133
0134   /** Make a clone of this object, possibly modifying the cloned object
0135    * to make it sane.
0136    * @return a pointer to the new object.
0137    */
0138   virtual IBPtr fullclone() const;
0139   //@}
0140
0141
0142 // If needed, insert declarations of virtual function defined in the
0143 // InterfacedBase class here (using ThePEG-interfaced-decl in Emacs).
0144
0145
0146 private:
0147
0148   /**
0149    * The assignment operator is private and must never be called.
0150    * In fact, it should not even be implemented.
0151    */
0152   FFMggxDipole & operator=(const FFMggxDipole &) = delete;
0153
0154 };
0155
0156 }
0157
0158 #endif /* HERWIG_FFMggxDipole_H */