Models/StandardModel/SMHGGVertex.h

0001 // -*- C++ -*-
0002 //
0003 // SMHGGVertex.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_SMHGGVertex_H
0010 #define HERWIG_SMHGGVertex_H
0011 //
0012 // This is the declaration of the SMHGGVertex class.
0013 //
0014
0015 #include "Herwig/Models/General/VVSLoopVertex.h"
0016 #include "Herwig/Models/StandardModel/StandardModel.h"
0017 #include "ThePEG/PDT/EnumParticles.h"
0018
0019 namespace Herwig {
0020 using namespace ThePEG;
0021
0022 /**
0023  * The <code>SMHGGVertex</code> class implements the
0024  * setCoupling member for the Standard Model effective
0025  * vertex Higgs-gluon-gluon.
0026  */
0027 class SMHGGVertex: public VVSLoopVertex {
0028
0029 public:
0030
0031   /**
0032    * The default constructor.
0033    */
0034   SMHGGVertex();
0035
0036   /** @name Functions used by the persistent I/O system. */
0037   //@{
0038   /**
0039    * Function used to write out object persistently.
0040    * @param os the persistent output stream written to.
0041    */
0042   void persistentOutput(PersistentOStream & os) const;
0043
0044   /**
0045    * Function used to read in object persistently.
0046    * @param is the persistent input stream read from.
0047    * @param version the version number of the object when written.
0048    */
0049   void persistentInput(PersistentIStream & is, int version);
0050   //@}
0051
0052   /**
0053    * The standard Init function used to initialize the interfaces.
0054    * Called exactly once for each class by the class description system
0055    * before the main function starts or
0056    * when this class is dynamically loaded.
0057    */
0058   static void Init();
0059
0060   /**
0061    * Calculate couplings
0062    *@param q2 Scale at which to evaluate coupling
0063    *@param part1 ParticleData pointer to first particle
0064    *@param part2 ParticleData pointer to first particle
0065    *@param part3 ParticleData pointer to first particle
0066    */
0067   virtual void setCoupling (Energy2 q2, tcPDPtr part1, tcPDPtr part2, tcPDPtr part3);
0068
0069 protected:
0070
0071   /** @name Clone Methods. */
0072   //@{
0073   /**
0074    * Make a simple clone of this object.
0075    * @return a pointer to the new object.
0076    */
0077   virtual IBPtr clone() const {return new_ptr(*this);}
0078
0079   /** Make a clone of this object, possibly modifying the cloned object
0080    * to make it sane.
0081    * @return a pointer to the new object.
0082    */
0083   virtual IBPtr fullclone() const {return new_ptr(*this);}
0084   //@}
0085
0086   /**
0087    * Initialize this object after the setup phase before saving and
0088    * EventGenerator to disk.
0089    * @throws InitException if object could not be initialized properly.
0090    */
0091   virtual void doinit();
0092
0093 private:
0094   /**
0095    * The assignment operator is private and must never be called.
0096    * In fact, it should not even be implemented.
0097    */
0098   SMHGGVertex & operator=(const SMHGGVertex &) = delete;
0099
0100   /**
0101    * Storage of couplings
0102    */
0103   //@{
0104   /**
0105    * Last value of the coupling calculated
0106    */
0107   Complex _couplast;
0108
0109   /**
0110    * The scale \f$q^2\f$ at which coupling was last evaluated
0111    */
0112   Energy2 _q2last;
0113   //@}
0114
0115   /**
0116    * Pointer to Standard Model object
0117    */
0118   tcHwSMPtr _theSM;
0119
0120   /**
0121    * Mass of W-boson for higgs coupling
0122    */
0123   Energy _mw;
0124
0125   /**
0126    * define quark mass scheme (fixed/running)
0127    */
0128   unsigned int massopt;
0129
0130   /**
0131    * The minimum flavour number in quark loops
0132    */
0133   int _minloop;
0134
0135   /**
0136    * The maximum flavour number in quark loops
0137    */
0138   int _maxloop;
0139
0140   /**
0141    * Loop calculations: A1 for spin-1/2 particles (see details in ``Higgs Hunter's Guide'')
0142    */
0143   Complex Af(double labmda) const;
0144
0145   /**
0146    * Loop calculations: W2 function (see details in NPB297,221)
0147    */
0148   Complex W2(double lambda) const;
0149
0150   /**
0151    * Switch between two representations of coefficients (_a00,_a11,_a12,_a21,_a22,_aEp):
0152    * suitable for the simplified H-g-g and H-gamma-gamma vertices and
0153    * suitable for the Passarino-Veltman tensor reduction scheme
0154    */
0155   unsigned int _CoefRepresentation;
0156
0157 };
0158
0159 }
0160
0161 // CLASSDOC OFF
0162
0163 #endif /* HERWIG_SMHGGVertex_H */