A class for the branching ratio of \(K\to\mu^+\mu^-\). More...

#include <BR_Kmumu.h>

Inheritance diagram for BR_Kmumu:

Detailed Description

A class for the branching ratio of \(K\to\mu^+\mu^-\).

Author: HEPfit Collaboration

Copyright: GNU General Public License

This class is used to compute the theoretical value of the branching ratio of \(K\to\mu^+\mu^-\).

Model parameters

The model parameters of BR_Kmumu are summarized below:

Label	LaTeX symbol	Description
Br_Kp_munu	\(\mathrm{BR}(K^+\to\mu^+\nu)\)	The experimental value for the branching ratio of \(K^+\to\mu^+\nu\).
DeltaP_cu	\(\)	The long-distance correction to the charm contribution of \(K^+\to\pi^+\nu\bar{\nu}\).

Definition at line 52 of file BR_Kmumu.h.

Public Member Functions
	BR_Kmumu (StandardModel &SM_i)

double	computeThValue ()

Public Member Functions inherited from ThObservable
double	getBinMax ()
	A get method to get the maximum value of the bin. More...

double	getBinMin ()
	A get method to get the minimum value of the bin. More...

const StandardModel &	getModel ()
	A get method to get the model. More...

const std::vector< std::string >	getParametersForObservable ()
	A get method to get the parameters for the specific observable. More...

void	setBinMax (double max)
	A set method to set the maximum value of the bin. More...

void	setBinMin (double min)
	A set method to set the minimum value of the bin. More...

void	setParametersForObservable (std::vector< std::string > parametersForObservable_i)
	A set method to get the parameters for the specific observable. More...

	ThObservable (const StandardModel &SM_i)
	Constructor. More...

	ThObservable (const ThObservable &orig)
	The copy constructor. More...

virtual	~ThObservable ()
	The default destructor. More...

Protected Member Functions
gslpp::complex	BRKmumu (orders order)

Private Attributes
CPenguinBoxMu	CPB

StandardModel &	mySM

Additional Inherited Members
Protected Attributes inherited from ThObservable
double	max
	the bin maximum. More...

double	min
	The bin minimum. More...

std::vector< std::string >	parametersForObservable
	a vector of parameter namesfor the specific observable More...

const StandardModel &	SM
	A reference to an object of StandardMode class. More...

Constructor & Destructor Documentation

◆ BR_Kmumu()

BR_Kmumu::BR_Kmumu ( StandardModel & SM_i )

constructor

Parameters

Flavour

Definition at line 13 of file BR_Kmumu.cpp.

 : ThObservable(SM_i), mySM(SM_i), CPB(SM)
 {
     setParametersForObservable(make_vector<std::string>() << "Br_Kp_munu" << "DeltaP_cu");
     mySM.initializeMeson(QCD::K_0);
     mySM.initializeMeson(QCD::K_P);
 }

Member Function Documentation

◆ BRKmumu()

gslpp::complex BR_Kmumu::BRKmumu ( orders order )

protected

Parameters

order
order_qed

Returns: the short distance contribution to the | \( BR(K_L \rightarrow \mu \bar{\mu}) \)|,

Definition at line 31 of file BR_Kmumu.cpp.

 {
     if (mySM.getFlavour().getHDS1().getCoeffDS1mumu().getOrder() < order){
         std::stringstream out;
         out << order;
         throw std::runtime_error("BRKmumu::computeThValue(): requires cofficient of "
                                  "order" + out.str() + "not computed");
     }
     
     gslpp::vector<gslpp::complex> ** allcoeff = mySM.getFlavour().ComputeCoeffDS1mumu();
     
     switch(order) {
         case NLO:
                 return((*(allcoeff[LO]) + *(allcoeff[NLO])) *
                        (*(allcoeff[LO]) + *(allcoeff[NLO]))
                        + CPB.X_ch() );
         case LO:
                 return((*(allcoeff[LO])) *
                        (*(allcoeff[LO]))
                        + CPB.X_ch() );
         default:
             std::stringstream out;
             out << order;
             throw std::runtime_error("BRKmumu::BRKmumu(): order " + out.str() + "not implemented");;
     }
 }

◆ computeThValue()

double BR_Kmumu::computeThValue ( )

virtual

Returns: theoretical value of | \( BR(K_L \rightarrow \mu \bar{\mu}) \)|, for example see hep-ph/0603079 section 2.3

Implements ThObservable.

Definition at line 21 of file BR_Kmumu.cpp.

 {
     double theta= asin(sqrt( (M_PI * mySM.getAle() )/( sqrt(2) * mySM.getGF() * 
                    mySM.Mw_tree() * mySM.Mw_tree()) ));
     
     return((mySM.getMesons(QCD::K_0).getLifetime() / HCUT / mySM.getMesons(QCD::K_P).getLifetime() / HCUT)
            * mySM.getAle()*mySM.getAle()/(2.*M_PI*M_PI*pow(sin(theta),4.)) 
            * mySM.getOptionalParameter("Br_Kp_munu") * BRKmumu(NLO).real());
 }

Member Data Documentation

◆ CPB

CPenguinBoxMu BR_Kmumu::CPB

private

Definition at line 82 of file BR_Kmumu.h.

◆ mySM

StandardModel& BR_Kmumu::mySM

private

Definition at line 81 of file BR_Kmumu.h.

The documentation for this class was generated from the following files: