EvtWilsonCoefficients.hh

Go to the documentation of this file.

 
/***********************************************************************
* Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
*                                                                      *
* This file is part of EvtGen.                                         *
*                                                                      *
* EvtGen is free software: you can redistribute it and/or modify       *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or    *
* (at your option) any later version.                                  *
*                                                                      *
* EvtGen is distributed in the hope that it will be useful,            *
* but WITHOUT ANY WARRANTY; without even the implied warranty of       *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
* GNU General Public License for more details.                         *
*                                                                      *
* You should have received a copy of the GNU General Public License    *
* along with EvtGen.  If not, see <https://www.gnu.org/licenses/>.     *
***********************************************************************/
 
#ifndef EVTWILSONCOEFICIENTS_HH
#define EVTWILSONCOEFICIENTS_HH
 
#include "EvtGenBase/EvtComplex.hh"
 
// Wilson coeficients according to A.J.Buras and M.Munz, Phys.Rev. D52, 186. (1995)
// Thanks to N. Nikitine for example code for Pythia
// Coefficient C8eff and C2 correction to C7eff taken from:
//   A.J.Buras, M.Misiak, M.Munz, S.Pokorski, Nucl.Phys. B424, 374 (1994)
//
// Used constants come from PDG 2004
 
class EvtWilsonCoefficients {
  public:
    EvtWilsonCoefficients();
    //~EvtWilsonCoefficients() {};
 
    // calculate strong coupling constant for n_f flavours and scale mu
    double alphaS( double mu, int n_f, double Lambda );
    // calculate Lambda matching alphaS using simple iterative method
    double Lambda( double alpha, int n_f, double mu, double epsilon, int maxstep );
    // eta-function: ratio of strong coupling constants
    double eta( double mu, int n_f, double Lambda, double M_W );
 
    // Wilson coeficients C1-C6
    EvtComplex C1( double mu, int n_f, double Lambda, double M_W );
    EvtComplex C2( double mu, int n_f, double Lambda, double M_W );
    EvtComplex C3( double mu, int n_f, double Lambda, double M_W );
    EvtComplex C4( double mu, int n_f, double Lambda, double M_W );
    EvtComplex C5( double mu, int n_f, double Lambda, double M_W );
    EvtComplex C6( double mu, int n_f, double Lambda, double M_W );
    // Wilson coeficietns C7,C8 => C7eff
    EvtComplex C7( double M_t, double M_W );
    EvtComplex C8( double M_t, double M_W );
    EvtComplex C7eff0( double mu, int n_f, double Lambda, double M_t, double M_W );
    EvtComplex C8eff0( double mu, int n_f, double Lambda, double M_t, double M_W );
    // Wilson coeficient C10
    EvtComplex C10tilda( double sin2W, double M_t, double M_W );
    EvtComplex C10( double sin2W, double M_t, double M_W, double ialpha );
    // Wilson coeficient C9
    double PE( double mu, int n_f, double Lambda, double M_W );
    EvtComplex P0( int ksi, double mu, int n_f, double Lambda, double M_W );
    EvtComplex C9tilda( int ksi, double mu, int n_f, double Lambda,
                        double sin2W, double M_t, double M_W );
    EvtComplex C9( int ksi, double mu, int n_f, double Lambda, double sin2W,
                   double M_t, double M_W, double ialpha );
 
    // Intermediate functions A-F,Y,Z
    double A( double x );
    double B( double x );
    double C( double x );
    double D( double x );
    double E( double x );
    double F( double x );
    double Y( double x );
    double Z( double x );
 
    // Mode decay specific functions
    EvtComplex hzs( double z, double shat, double mu, double M_b );
    double fz( double z );
    double kappa( double z, double alpha_S );
    double etatilda( double shat, double alpha_S );
    double omega( double shat );
    EvtComplex C9efftilda( double z, double shat, double alpha_S, EvtComplex c1,
                           EvtComplex c2, EvtComplex c3, EvtComplex c4,
                           EvtComplex c5, EvtComplex c6, EvtComplex c9tilda,
                           int ksi );
    EvtComplex C7b2sg( double alpha_S, double et, EvtComplex c2, double M_t,
                       double M_W );
    EvtComplex Yld( double q2, double ki[], double Gi[], double Mi[], int ni,
                    EvtComplex c1, EvtComplex c2, EvtComplex c3, EvtComplex c4,
                    EvtComplex c5, EvtComplex c6, double ialpha );
 
    // User function
    void CalculateAllCoefficients();
    // Set parameters
    void SetLambda( double lambda ) { m_Lambda = lambda; }
    void CalculateLambda( double epsilon, int maxstep )
    {
        m_Lambda = Lambda( m_alphaMZ, m_n_f, m_mu, epsilon, maxstep );
    }
    void SetStrongCouplingAtZMass( double alphaMZ ) { m_alphaMZ = alphaMZ; }
    void SetScale( double mu ) { m_mu = mu; }
    void SetNumberOfFlavours( int n_f ) { m_n_f = n_f; }
    void SetZMass( double M_Z ) { m_M_Z = M_Z; }
    void SetWMass( double M_W ) { m_M_W = M_W; }
    void SetTopMass( double M_t ) { m_M_t = M_t; }
    void SetSin2WeinbergAngle( double sin2W ) { m_sin2W = sin2W; }
    void SetInvElMagCoupling( double ialpha ) { m_ialpha = ialpha; }
    void SetRenormalizationScheme( std::string scheme );
    // Get parameters
    double GetLambda() { return m_Lambda; }
    double GetStrongCouplingAtZMass() { return m_alphaMZ; }
    double GetStrongCouplingConst() { return m_alphaS; }
    double GetScale() { return m_mu; }
    int GetNumberOfFlavours() { return m_n_f; }
    int GetRenormSchemePar() { return m_ksi; }
    double GetZMass() { return m_M_Z; }
    double GetWMass() { return m_M_W; }
    double GetTopMass() { return m_M_t; }
    double GetSin2WeinbergAngle() { return m_sin2W; }
    double GetInvElMagCoupling() { return m_ialpha; }
    double GetEta() { return m_eta; }
    // Get results
    double GetA() { return m_A; }
    double GetB() { return m_B; }
    double GetC() { return m_C; }
    double GetD() { return m_D; }
    double GetE() { return m_E; }
    double GetF() { return m_F; }
    double GetY() { return m_Y; }
    double GetZ() { return m_Z; }
    EvtComplex GetC1() { return m_C1; }
    EvtComplex GetC2() { return m_C2; }
    EvtComplex GetC3() { return m_C3; }
    EvtComplex GetC4() { return m_C4; }
    EvtComplex GetC5() { return m_C5; }
    EvtComplex GetC6() { return m_C6; }
    EvtComplex GetC7() { return m_C7; }
    EvtComplex GetC8() { return m_C8; }
    EvtComplex GetC9() { return m_C9; }
    EvtComplex GetC10() { return m_C10; }
    EvtComplex GetC7eff0() { return m_C7eff0; }
    EvtComplex GetC8eff0() { return m_C8eff0; }
    EvtComplex GetC9tilda() { return m_C9tilda; }
    EvtComplex GetC10tilda() { return m_C10tilda; }
    EvtComplex GetP0() { return m_P0; }
    double GetPE() { return m_PE; }
 
  private:
    int m_n_f, m_ksi;
    double m_Lambda, m_alphaMZ, m_mu, m_M_Z, m_M_t, m_M_W, m_alphaS, m_eta,
        m_sin2W, m_ialpha;
    EvtComplex m_C1, m_C2, m_C3, m_C4, m_C5, m_C6, m_C7, m_C7eff0, m_C8,
        m_C8eff0, m_C9, m_C9tilda, m_C10, m_C10tilda, m_P0;
    double m_A, m_B, m_C, m_D, m_E, m_F, m_Y, m_Z, m_PE;
 
    double m_k[6][8], m_a[8], m_h[8], m_p[8], m_r[2][8], m_s[8], m_q[8], m_g[8];
};
 
#endif