Matchbox/Dipoles/FFMsqgxDipole.h

0001 // -*- C++ -*-
0002 //
0003 // FFMsqgxDipole.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_FFMsqgxDipole_H
0010 #define HERWIG_FFMsqgxDipole_H
0011 //
0012 // This is the declaration of the FFMsqgxDipole 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, Alexandra Wilcock, Christian Reuschle
0024  *
0025  * \brief FFMsqgxDipole implements the D_{sq,g;k} subtraction dipole.
0026  *
0027  */
0028 class FFMsqgxDipole: public SubtractionDipole {
0029
0030 public:
0031
0032   /**
0033    * The default constructor.
0034    */
0035   FFMsqgxDipole();
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
0045       emitter > 1 &&
0046       (abs(abs(partons[emitter]->id()) - 1000000) < 7 || abs(abs(partons[emitter]->id()) - 2000000) < 7);
0047   }
0048
0049   /**
0050    * Return true, if this dipole can possibly handle the indicated
0051    * splitting.
0052    */
0053   virtual bool canHandleSplitting(const cPDVector& partons, int emitter, int emission) const {
0054     return
0055       canHandleEmitter(partons,emitter) &&
0056       partons[emission]->id() == ParticleID::g;
0057   }
0058
0059   /**
0060    * Return true, if this dipole can possibly handle the indicated
0061    * spectator.
0062    */
0063   virtual bool canHandleSpectator(const cPDVector& partons, int spectator) const {
0064     return spectator > 1 && partons[spectator]->coloured();
0065   }
0066
0067   /**
0068    * Return true, if this dipole applies to the selected
0069    * configuration.
0070    */
0071   virtual bool canHandle(const cPDVector& partons,
0072              int emitter, int emission, int spectator) const;
0073
0074   /**
0075    *  How to sample the z-distribution.
0076    *  FlatZ = 1
0077    *  OneOverZ = 2
0078    *  OneOverOneMinusZ = 3
0079    *  OneOverZOneMinusZ = 4
0080    */
0081
0082   virtual int samplingZ() const {return 3;}
0083
0084   /**
0085    * Return the matrix element for the kinematical configuation
0086    * previously provided by the last call to setKinematics(), suitably
0087    * scaled by sHat() to give a dimension-less number.
0088    */
0089   virtual double me2() const;
0090
0091   /**
0092    * Return the matrix element averaged over spin correlations.
0093    */
0094   virtual double me2Avg(double ccme2) const;
0095
0096 public:
0097
0098   /** @name Functions used by the persistent I/O system. */
0099   //@{
0100   /**
0101    * Function used to write out object persistently.
0102    * @param os the persistent output stream written to.
0103    */
0104   void persistentOutput(PersistentOStream & os) const;
0105
0106   /**
0107    * Function used to read in object persistently.
0108    * @param is the persistent input stream read from.
0109    * @param version the version number of the object when written.
0110    */
0111   void persistentInput(PersistentIStream & is, int version);
0112   //@}
0113
0114   /**
0115    * The standard Init function used to initialize the interfaces.
0116    * Called exactly once for each class by the class description system
0117    * before the main function starts or
0118    * when this class is dynamically loaded.
0119    */
0120   static void Init();
0121
0122 protected:
0123
0124   /** @name Clone Methods. */
0125   //@{
0126   /**
0127    * Make a simple clone of this object.
0128    * @return a pointer to the new object.
0129    */
0130   virtual IBPtr clone() const;
0131
0132   /** Make a clone of this object, possibly modifying the cloned object
0133    * to make it sane.
0134    * @return a pointer to the new object.
0135    */
0136   virtual IBPtr fullclone() const;
0137   //@}
0138
0139
0140 // If needed, insert declarations of virtual function defined in the
0141 // InterfacedBase class here (using ThePEG-interfaced-decl in Emacs).
0142
0143
0144 private:
0145
0146   /**
0147    * The assignment operator is private and must never be called.
0148    * In fact, it should not even be implemented.
0149    */
0150   FFMsqgxDipole & operator=(const FFMsqgxDipole &) = delete;
0151
0152 };
0153
0154 }
0155
0156 #endif /* HERWIG_FFMsqgxDipole_H */