MEPP2HiggsPowheg.h

// -*- C++ -*-
//
// MEPP2HiggsPowheg.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_MEPP2HiggsPowheg_H
#define HERWIG_MEPP2HiggsPowheg_H
//
// This is the declaration of the MEPP2HiggsPowheg class.
//
 
#include "Herwig/MatrixElement/Hadron/MEPP2Higgs.h"
#include "ThePEG/PDF/BeamParticleData.h"
 
namespace Herwig {
using namespace ThePEG;
using namespace ThePEG::Helicity;
 
class MEPP2HiggsPowheg: public MEPP2Higgs {
 
public:
 
  MEPP2HiggsPowheg();
 
public:
 
  virtual double me2() const;
 
  virtual bool generateKinematics(const double * r);
 
  virtual Energy2 scale() const;
 
  virtual int nDim() const;
 
public:
 
  void persistentOutput(PersistentOStream & os) const;
 
  void persistentInput(PersistentIStream & is, int version);
 
  static void Init();
 
  void get_born_variables() const;
 
  double NLOweight() const;
 
  Energy2 s(double xt, double y) const {
    return  p2_/x(xt,y);
  }
 
  Energy2 tk(double xt, double y) const {
    double  x_xt_y(x(xt,y));
    return -0.5*p2_/x_xt_y*(1.- x_xt_y)*(1.-y);
  }
 
  Energy2 uk(double xt, double y) const {
    double  x_xt_y(x(xt,y));
    return -0.5*p2_/x_xt_y*(1.- x_xt_y)*(1.+y);
  }
 
  double xbar(double y) const;
 
  double etabar(double y) const;
 
  double x(double xt, double y) const {
    double x0(xbar(y));
    return x0+(1.-x0)*xt;
  }
 
  double xp(double x, double y) const;
 
  double xm(double x, double y) const;
 
  double Lhat_ab(tcPDPtr a, tcPDPtr b, double x, double y) const;
 
  double Vtilde_universal() const;
 
  double Ctilde_Ltilde_gg_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Ctilde_Ltilde_qg_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Ctilde_Ltilde_gq_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double M_V_regular() const;
 
  Energy2 t_u_M_R_qqbar(double xt, double y) const;
 
  Energy2 t_u_M_R_qbarq(double xt, double y) const;
 
  Energy2 t_u_M_R_gg(double xt, double y) const;
 
  Energy2 t_u_M_R_qg(double xt, double y) const;
 
  Energy2 t_u_M_R_gq(double xt, double y) const;
 
  double Rtilde_Ltilde_qqbar_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Rtilde_Ltilde_qbarq_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Rtilde_Ltilde_gg_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Rtilde_Ltilde_qg_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
  double Rtilde_Ltilde_gq_on_x(tcPDPtr a,tcPDPtr b,double xt,double y) const;
 
protected:
 
  virtual IBPtr clone() const { return new_ptr(*this); }
 
  virtual IBPtr fullclone() const { return new_ptr(*this); }
 
private:
 
  MEPP2HiggsPowheg & operator=(const MEPP2HiggsPowheg &) = delete;
 
private:
 
  const double CF_ , CA_ , TR_;
 
  const int nlf_;
 
  const double beta0_;
 
  unsigned int contrib_;
 
  unsigned int nlo_alphaS_opt_;
 
  double fixed_alphaS_;
 
  double xt_;
 
  double y_;
 
  mutable double lo_lumi_;
 
  mutable double lo_ggME_;
 
  mutable Energy2 p2_      ;
 
  mutable Energy2 s2_      ;
 
  mutable double xbp_;
 
  mutable double  xbm_;
 
  mutable double etabarp_;
 
  mutable double etabarm_;
 
  mutable tcPDPtr a_lo_;
 
  mutable tcPDPtr b_lo_;
 
  mutable Ptr<BeamParticleData>::transient_const_pointer hadron_A_;
 
  mutable Ptr<BeamParticleData>::transient_const_pointer hadron_B_;
 
  mutable double alphaS_;
 
  unsigned int scaleopt_;
 
  Energy mu_F_;
 
  Energy mu_UV_;
 
  double scaleFact_;
};
 
}
 
#endif /* HERWIG_MEPP2HiggsPowheg_H */