ThePEG/MatrixElement/MEQQ2qq2.h

0001 // -*- C++ -*-
0002 //
0003 // MEQQ2qq2.h is a part of ThePEG - Toolkit for HEP Event Generation
0004 // Copyright (C) 1999-2019 Leif Lonnblad
0005 //
0006 // ThePEG 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 ThePEG_MEQQ2qq_H
0010 #define ThePEG_MEQQ2qq_H
0011 // This is the declaration of the MEQQ2qq class.
0012
0013 #include "ThePEG/MatrixElement/ME2to2QCD.h"
0014
0015 namespace ThePEG {
0016
0017 /**
0018  * MEQQ2qq inherits from ME2to2QCD and implements the standard
0019  * \f$q\bar{q}\rightarrow q'\bar{q'}\f$ matrix element.
0020  *
0021  * @see \ref MEQQ2qqInterfaces "The interfaces"
0022  * defined for MEQQ2qq.
0023  * @see ME2to2QCD
0024  */
0025 class MEQQ2qq: public ME2to2QCD {
0026
0027 public:
0028
0029   /** @name Virtual functions required by the MEBase class. */
0030   //@{
0031   /**
0032    * The matrix element for the kinematical configuration
0033    * previously provided by the last call to setKinematics(), suitably
0034    * scaled by sHat() to give a dimension-less number.
0035    * @return the matrix element scaled with sHat() to give a
0036    * dimensionless number.
0037    */
0038   virtual double me2() const;
0039
0040   /**
0041    * Add all possible diagrams with the add() function.
0042    */
0043   virtual void getDiagrams() const;
0044
0045   /**
0046    * Return a Selector with possible colour geometries for the selected
0047    * diagram weighted by their relative probabilities.
0048    * @param diag the diagram chosen.
0049    * @return the possible colour geometries weighted by their
0050    * relative probabilities.
0051    */
0052   virtual Selector<const ColourLines *>
0053   colourGeometries(tcDiagPtr diag) const;
0054
0055   /**
0056    * Get diagram selector. With the information previously supplied with the
0057    * setKinematics method, a derived class may optionally
0058    * override this method to weight the given diagrams with their
0059    * (although certainly not physical) relative probabilities.
0060    * @param dv the diagrams to be weighted.
0061    * @return a Selector relating the given diagrams to their weights.
0062    */
0063   virtual Selector<DiagramIndex> diagrams(const DiagramVector & dv) const;
0064   //@}
0065
0066 protected:
0067
0068   /** @name Internal functions returning the matrix element squared
0069    *  for different colour configurations. */
0070   //@{
0071   /**
0072    * Return the matrix element squared (without common pre-factors)
0073    * for the specific colour configuration.
0074    */
0075   double colA() const
0076   {
0077     return (sqr(uHat()) + sqr(tHat()))/sqr(sHat());
0078   }
0079   //@}
0080
0081 public:
0082
0083   /**
0084    * Standard Init function used to initialize the interfaces.
0085    */
0086   static void Init();
0087
0088 protected:
0089
0090   /** @name Clone Methods. */
0091   //@{
0092   /**
0093    * Make a simple clone of this object.
0094    * @return a pointer to the new object.
0095    */
0096   virtual IBPtr clone() const { return new_ptr(*this); }
0097
0098   /** Make a clone of this object, possibly modifying the cloned object
0099    * to make it sane.
0100    * @return a pointer to the new object.
0101    */
0102   virtual IBPtr fullclone() const { return new_ptr(*this); }
0103   //@}
0104
0105 private:
0106
0107   /**
0108    * Describe a concrete class without persistent data.
0109    */
0110   static NoPIOClassDescription<MEQQ2qq> initMEQQ2qq;
0111
0112   /**
0113    *  Private and non-existent assignment operator.
0114    */
0115   MEQQ2qq & operator=(const MEQQ2qq &) = delete;
0116
0117 };
0118
0119 }
0120
0121
0122 namespace ThePEG {
0123
0124 /** @cond TRAITSPECIALIZATIONS */
0125
0126 /** This template specialization informs ThePEG about the
0127  *  base classes of MEQQ2qq. */
0128 template <>
0129 struct BaseClassTrait<MEQQ2qq,1>: public ClassTraitsType {
0130   /** Typedef of the first base class of MEQQ2qq. */
0131   typedef ME2to2QCD NthBase;
0132 };
0133
0134 /** This template specialization informs ThePEG about the name of
0135  *  the MEQQ2qq class and the shared object where it is defined. */
0136 template <>
0137 struct ClassTraits<MEQQ2qq>: public ClassTraitsBase<MEQQ2qq> {
0138   /** Return a platform-independent class name */
0139   static string className() { return "ThePEG::MEQQ2qq"; }
0140   /** Return the name of the shared library be loaded to get
0141    *  access to the MEQQ2qq class and every other class it uses
0142    *  (except the base class). */
0143   static string library() { return "MEQCD.so"; }
0144 };
0145
0146 /** @endcond */
0147
0148 }
0149
0150 #endif /* ThePEG_MEQQ2qq_H */