Matchbox/Dipoles/FFqqxDipole.h

0001 // -*- C++ -*-
0002 //
0003 // FFqqxDipole.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_FFqqxDipole_H
0010 #define HERWIG_FFqqxDipole_H
0011 //
0012 // This is the declaration of the FFqqxDipole 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
0024  *
0025  * \brief FFqqxDipole implements the D_{q,qbar;k} subtraction dipole.
0026  *
0027  */
0028 class FFqqxDipole: public SubtractionDipole {
0029
0030 public:
0031
0032   /**
0033    * The default constructor.
0034    */
0035   FFqqxDipole();
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 && abs(partons[emitter]->id()) < 7;
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
0053       canHandleEmitter(partons,emitter) &&
0054       partons[emitter]->id() + partons[emission]->id() == 0;
0055   }
0056
0057   /**
0058    * Return true, if this dipole can possibly handle the indicated
0059    * spectator.
0060    */
0061   virtual bool canHandleSpectator(const cPDVector& partons, int spectator) const {
0062     return spectator > 1 && partons[spectator]->coloured();
0063   }
0064
0065   /**
0066    * Return true, if this dipole applies to the selected
0067    * configuration.
0068    */
0069   virtual bool canHandle(const cPDVector& partons,
0070              int emitter, int emission, int spectator) const;
0071
0072   /**
0073    *  How to sample the z-distribution.
0074    *  FlatZ = 1
0075    *  OneOverZ = 2
0076    *  OneOverOneMinusZ = 3
0077    *  OneOverZOneMinusZ = 4
0078    */
0079
0080   virtual int samplingZ() const {return 1;}
0081
0082   /**
0083    * Return true, if this dipole is symmetric with respect to emitter
0084    * and emission.
0085    */
0086   virtual bool isSymmetric() const { return true; }
0087
0088   /**
0089    * Return the matrix element for the kinematical configuation
0090    * previously provided by the last call to setKinematics(), suitably
0091    * scaled by sHat() to give a dimension-less number.
0092    */
0093   virtual double me2() const;
0094
0095   /**
0096    * Return the matrix element averaged over spin correlations.
0097    */
0098   virtual double me2Avg(double ccme2) const;
0099
0100 public:
0101
0102   /** @name Functions used by the persistent I/O system. */
0103   //@{
0104   /**
0105    * Function used to write out object persistently.
0106    * @param os the persistent output stream written to.
0107    */
0108   void persistentOutput(PersistentOStream & os) const;
0109
0110   /**
0111    * Function used to read in object persistently.
0112    * @param is the persistent input stream read from.
0113    * @param version the version number of the object when written.
0114    */
0115   void persistentInput(PersistentIStream & is, int version);
0116   //@}
0117
0118   /**
0119    * The standard Init function used to initialize the interfaces.
0120    * Called exactly once for each class by the class description system
0121    * before the main function starts or
0122    * when this class is dynamically loaded.
0123    */
0124   static void Init();
0125
0126 protected:
0127
0128   /** @name Clone Methods. */
0129   //@{
0130   /**
0131    * Make a simple clone of this object.
0132    * @return a pointer to the new object.
0133    */
0134   virtual IBPtr clone() const;
0135
0136   /** Make a clone of this object, possibly modifying the cloned object
0137    * to make it sane.
0138    * @return a pointer to the new object.
0139    */
0140   virtual IBPtr fullclone() const;
0141   //@}
0142
0143
0144 // If needed, insert declarations of virtual function defined in the
0145 // InterfacedBase class here (using ThePEG-interfaced-decl in Emacs).
0146
0147
0148 private:
0149
0150   /**
0151    * The assignment operator is private and must never be called.
0152    * In fact, it should not even be implemented.
0153    */
0154   FFqqxDipole & operator=(const FFqqxDipole &) = delete;
0155
0156 };
0157
0158 }
0159
0160 #endif /* HERWIG_FFqqxDipole_H */