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 // -*- C++ -*-
 //
 // SMHiggsWidthGenerator.h is a part of Herwig - A multi-purpose Monte Carlo event generator
 // Copyright (C) 2002-2019 The Herwig Collaboration
 //
 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 #ifndef HERWIG_SMHiggsWidthGenerator_H
 #define HERWIG_SMHiggsWidthGenerator_H
 //
 // This is the declaration of the SMHiggsWidthGenerator class.
 //
 
 #include "GenericWidthGenerator.h"
 
 namespace Herwig {
 using namespace ThePEG;
 
 /**
  * The SMHiggsWidthGenerator class calculates the width for the Standard Model 
  * Higgs boson
  *
  * @see \ref SMHiggsWidthGeneratorInterfaces "The interfaces"
  * defined for SMHiggsWidthGenerator.
  */
 class SMHiggsWidthGenerator: public GenericWidthGenerator {
 
 public:
 
   /**
    * The default constructor.
    */
   SMHiggsWidthGenerator() 
     : widthopt_(2), offshell_(10.), mw_(ZERO), mz_(ZERO), gamw_(ZERO),
       gamz_(ZERO), qmass_(7,ZERO), lmass_(3,ZERO),
       sw2_(0.), ca_(0.), cf_(0.), qlast_(ZERO)
   {}
 
 private:
 
 
   /** @name Virtual functions to be overridden from based class */
   //@{
   /**
    * Given a particle type and a mass of an instance of that particle
    * type, calculate a width.
    */
   virtual Energy width(const ParticleData &, Energy m) const;
 
   /**
    * Return decay map for the given particle type.
    */
   virtual DecayMap rate(const ParticleData &) const;
 
   /**
    * Return a decay map for a given Particle instance.
    */
   virtual DecayMap rate(const Particle &);
   //@}
 
   /**
    *  Return the total width and the sum of the partial widths for
    *  modes which are used
    */
   virtual pair<Energy,Energy> width(Energy, const ParticleData &) const;
 
   /**
    *  Calculate the partial width for a given mode
    * @param mH The Higgs masses
    * @param imode The decay mode
    */
   Energy partialWidth(int imode, Energy mH) const;
 
 public:
 
   /** @name Functions used by the persistent I/O system. */
   //@{
   /**
    * Function used to write out object persistently.
    * @param os the persistent output stream written to.
    */
   void persistentOutput(PersistentOStream & os) const;
 
   /**
    * Function used to read in object persistently.
    * @param is the persistent input stream read from.
    * @param version the version number of the object when written.
    */
   void persistentInput(PersistentIStream & is, int version);
   //@}
 
   /**
    * The standard Init function used to initialize the interfaces.
    * Called exactly once for each class by the class description system
    * before the main function starts or
    * when this class is dynamically loaded.
    */
   static void Init();
 
 protected:
 
   /** @name Clone Methods. */
   //@{
   /**
    * Make a simple clone of this object.
    * @return a pointer to the new object.
    */
   virtual IBPtr clone() const;
 
   /** Make a clone of this object, possibly modifying the cloned object
    * to make it sane.
    * @return a pointer to the new object.
    */
   virtual IBPtr fullclone() const;
   //@}
 
 protected:
 
   /** @name Routines to calculate Higgs width. */
   //@{
   /**
    * Calculates the double Breit-Wigner Integral a-la FORTRAN HERWIG.
    * It is used in NLL corrected Higgs width for H->WW/ZZ,
    * x = (M_V/M_H)^2, y=M_V*G_V/(M_H)^2, where M_V/G_V - V-boson mass/width
    * @return the integral value.
    */
   double HwDoubleBW(double x, double y) const;
 
   /**
    * Calculate a loop function for the triangle vertex GGH/AAH
    * @return the loop function value as a complex number
    */
   Complex HwW2(double tau) const;
   //@}
 
   /**
    *  Return the branching ratios at the given scale
    * @param scale The off shell-mass of the Higgs 
    */
   DecayMap branching(Energy scale, const ParticleData &) const;
 
 protected:
 
   /** @name Standard Interfaced functions. */
   //@{
   /**
    * Initialize this object after the setup phase before saving an
    * EventGenerator to disk.
    * @throws InitException if object could not be initialized properly.
    */
   virtual void doinit();
   //@}
 
 
 private:
 
   /**
    * The assignment operator is private and must never be called.
    * In fact, it should not even be implemented.
    */
   SMHiggsWidthGenerator & operator=(const SMHiggsWidthGenerator &) = delete;
 
 private:
 
   /**
    * Type of the Higgs width used (options: fixed, LO running, NLL corrected running)
    */
   unsigned int widthopt_;
 
   /**
    *  Number of times the width the Higgs is allowed to be off-shell
    */
   double offshell_;
 
   /**
    *  Particle properties extracted at initialization
    */
   //@{
   /**
    *  Mass of the W boson
    */
   Energy mw_;
 
   /**
    *  Mass of the Z boson
    */
   Energy mz_;
 
   /**
    *  Width of the W boson
    */
   Energy gamw_;
 
   /**
    *  Width of the Z boson
    */
   Energy gamz_;
 
   /**
    *  Masses of the quarks
    */
   vector<Energy> qmass_;
 
   /**
    *  Masses of the leptons
    */
   vector<Energy> lmass_;
 
   /**
    *  \f$\sin^2\theta_W\f$
    */
   double sw2_;
 
   /**
    *  The \f$C_A\f$ colour factor
    */
   double ca_;
 
   /**
    *  The \f$C_F\f$ colour factor
    */
   double cf_;
   //@}
 
   /**
    * Storage of parameters for speed
    */
   //@{
   /**
    *  The last scale
    */
   mutable Energy qlast_;
 
   /**
    *  \f$\Lambda_{\rm QCD}\f$
    */
   mutable Energy lambdaQCD_;
 
   /**
    *  The electromagnetic coupling
    */
   mutable double alphaEM_;
 
   /**
    *  The strong coupling
    */
   mutable double alphaS_;
 
   /**
    *  Correction factor for \f$H\to q\bar{q}\f$
    */
   mutable double cd_;
 
   /**
    *  Fermi constant
    */
   mutable Energy2 gfermiinv_;
 
   /**
    *  The anomalous dimension for  \f$H\to q\bar{q}\f$
    */
   mutable double gam0_;
 
   /**
    *  The \f$\beta\f$ function coefficient for  \f$H\to q\bar{q}\f$
    */
   mutable double beta0_;
   //@}
 
   /**
    *  Map between location in decay modes vector and code here
    */
   map<int,int> locMap_;
 };
 
 }
 
 #endif /* HERWIG_SMHiggsWidthGenerator_H */

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