Builtin/Amplitudes/MatchboxAmplitudelnuqqbarqqbar.h

0001 // -*- C++ -*-
0002 //
0003 // MatchboxAmplitudelnuqqbarqqbar.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_MatchboxAmplitudelnuqqbarqqbar_H
0010 #define Herwig_MatchboxAmplitudelnuqqbarqqbar_H
0011 //
0012 // This is the declaration of the MatchboxAmplitudelnuqqbarqqbar class.
0013 //
0014
0015 #include "Herwig/MatrixElement/Matchbox/Base/MatchboxAmplitude.h"
0016 #include "Herwig/MatrixElement/Matchbox/Builtin/Amplitudes/MatchboxCurrents.h"
0017 #include "Herwig/MatrixElement/Matchbox/Utility/SU2Helper.h"
0018 #include "ThePEG/StandardModel/StandardModelBase.h"
0019 #include "ThePEG/Interface/ClassDocumentation.h"
0020 #include "ThePEG/Interface/Switch.h"
0021 #include "ThePEG/Interface/Parameter.h"
0022 #include "ThePEG/EventRecord/Particle.h"
0023 #include "ThePEG/Repository/UseRandom.h"
0024 #include "ThePEG/Repository/EventGenerator.h"
0025 #include "ThePEG/Utilities/DescribeClass.h"
0026 #include "ThePEG/Persistency/PersistentOStream.h"
0027 #include "ThePEG/Persistency/PersistentIStream.h"
0028 #include "ThePEG/PDT/EnumParticles.h"
0029
0030 namespace Herwig {
0031
0032 using namespace ThePEG;
0033
0034 /**
0035  * \ingroup Matchbox
0036  * \author Thomas Schuh
0037  *
0038  * \brief MatchboxAmplitudelnuqqbarqqbar
0039  */
0040 class MatchboxAmplitudelnuqqbarqqbar: public MatchboxAmplitude, public MatchboxCurrents {
0041
0042 public:
0043
0044   /**
0045    * The default constructor.
0046    */
0047   MatchboxAmplitudelnuqqbarqqbar();
0048
0049   /**
0050    * Return the (tree-level) order in \f$g_S\f$ in which this matrix
0051    * element is given.
0052    */
0053   virtual unsigned int orderInGs() const { return 2; }
0054
0055   /**
0056    * Return the (tree-level) order in \f$g_{EM}\f$ in which this matrix
0057    * element is given.
0058    */
0059   virtual unsigned int orderInGem() const { return 2; }
0060
0061   /**
0062    * Return true, if this amplitude is capable of calculating one-loop
0063    * (QCD) corrections.
0064    */
0065   virtual bool haveOneLoop() const { return false; }
0066
0067   /**
0068    * Return true, if this amplitude can handle the given process.
0069    */
0070   virtual bool canHandle(const PDVector&) const;
0071
0072   /**
0073    * Calculate the tree level amplitudes for the phasespace point
0074    * stored in lastXComb.
0075    */
0076   virtual void prepareAmplitudes(Ptr<MatchboxMEBase>::tcptr);
0077
0078   /**
0079    * Evaluate the amplitude for the given colour tensor id and
0080    * helicity assignment
0081    */
0082   virtual Complex evaluate(size_t, const vector<int>&, Complex&);
0083
0084   /**
0085    * Return true, if one loop corrections are given in the conventions
0086    * of BDK.
0087    */
0088   virtual bool isBDK() const { return true; }
0089
0090   /**
0091    * Return the value of the dimensional regularization
0092    * parameter. Note that renormalization scale dependence is fully
0093    * restored in DipoleIOperator.
0094    */
0095   virtual Energy2 mu2() const { return lastSHat(); }
0096
0097   /**
0098    * Flush all cashes.
0099    */
0100   virtual void flushCaches() {
0101     MatchboxCurrents::reset();
0102     MatchboxAmplitude::flushCaches();
0103   }
0104
0105   /**
0106    * Function used to write out object persistently.
0107    * @param os the persistent output stream written to.
0108    */
0109   void persistentOutput(PersistentOStream & os) const;
0110
0111   /**
0112    * Function used to read in object persistently.
0113    * @param is the persistent input stream read from.
0114    * @param version the version number of the object when written.
0115    */
0116   void persistentInput(PersistentIStream & is, int version);
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   /**
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    * Initialize this object after the setup phase before saving an
0142    * EventGenerator to disk.
0143    * @throws InitException if object could not be initialized properly.
0144    */
0145   virtual void doinit();
0146
0147   /**
0148    * Initialize this object. Called in the run phase just before
0149    * a run begins.
0150    */
0151   virtual void doinitrun();
0152
0153 private:
0154
0155   /**
0156    * True, if a diagonal CKM matrix should be assumed. This ignores
0157    * the CKM object of the StandardModel.
0158    */
0159   bool theDiagonal;
0160
0161   /**
0162    * The ckm.
0163    */
0164   vector< vector<Complex> > theCKM;
0165
0166   /**
0167    * The assignment operator is private and must never be called.
0168    * In fact, it should not even be implemented.
0169    */
0170   MatchboxAmplitudelnuqqbarqqbar & operator=(const MatchboxAmplitudelnuqqbarqqbar &) = delete;
0171
0172 };
0173
0174 }
0175
0176 #endif /* Herwig_MatchboxAmplitudelnuqqbarqqbar_H */