QCD Library
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MSbar_mass Class Reference

Implements the running and decoupling of a quark mass in the $\overline{\rm MS}$ scheme. More...

Public Member Functions

 MSbar_mass (reference_mass m, strong_coupling alpha_s, int order=max_running_order)
 
 MSbar_mass (reference_mass m, double alpha_s_mu, int order=max_running_order)
 
double operator() (double scale) const
 
MSbar_mass decouple_down (threshold thr) const
 Decouple down (remove) flavour in running of mass. More...
 
MSbar_mass remove (threshold thr) const
 Remove (decouple down) flavour in running of mass. More...
 
MSbar_mass decouple_up (threshold thr) const
 Decouple up (add) flavour in running. More...
 
MSbar_mass add (threshold thr) const
 Add (decouple up) flavour in running. More...
 
double to_scale_invariant (double ep) const
 
template<typename... T>
double to_SI (T &&... t) const
 
int order () const
 
int nf () const
 
Parameters with_alpha_s (double scale) const
 
MSbar_masserror (double err)
 Set error bounds for evolution. More...
 
MSbar_massabs_error (double abs_err)
 Set absolute error bound for evolution. More...
 
MSbar_massrel_error (double rel_err)
 Set relative error bound for evolution. More...
 

Static Public Attributes

static constexpr int max_running_order
 Highest running order.
 
static constexpr double default_error = 1e-6
 Default (relative and absolute) running error.
 

Detailed Description

Implements the running and decoupling of a quark mass in the $\overline{\rm MS}$ scheme.

Constructor & Destructor Documentation

◆ MSbar_mass() [1/2]

MSbar_mass ( reference_mass  m,
strong_coupling  alpha_s,
int  order = max_running_order 
)

Construct an $\overline{\rm MS}$ mass

Parameters
mReference mass with the corresponding scale and number of active quark flavours
alpha_sStrong coupling constant
orderRunning order between 0 and max_running_order
See also
#strong_coupling

◆ MSbar_mass() [2/2]

MSbar_mass ( reference_mass  m,
double  alpha_s_mu,
int  order = max_running_order 
)

Construct an $\overline{\rm MS}$ mass

Parameters
mReference mass with the corresponding scale and number of active quark flavours
orderRunning order between 0 and max_running_order
alpha_s_muValue of the strong coupling constant at the reference scale m.mu
See also
#strong_coupling

Member Function Documentation

◆ operator()()

double operator() ( double  scale) const

Evolve the mass to the given scale

Parameters
scaleTarget scale for the evolution
Returns
The value of the mass at the given scale

◆ decouple_down()

MSbar_mass decouple_down ( threshold  thr) const

Decouple down (remove) flavour in running of mass.

Parameters
thrThe decoupling threshold
Returns
The mass with nf - 1 active flavours

◆ remove()

MSbar_mass remove ( threshold  thr) const

Remove (decouple down) flavour in running of mass.

Parameters
thrThe decoupling threshold
Returns
The mass with nf - 1 active flavours

◆ decouple_up()

MSbar_mass decouple_up ( threshold  thr) const

Decouple up (add) flavour in running.

Parameters
thrThe decoupling threshold
Returns
The mass with nf + 1 active flavours

◆ add()

MSbar_mass add ( threshold  thr) const

Add (decouple up) flavour in running.

Parameters
thrThe decoupling threshold
Returns
The mass with nf + 1 active flavours

◆ to_scale_invariant()

double to_scale_invariant ( double  ep) const

Compute the scale-invariant mass $m(m)$

Returns
The scale-invariant mass Compute the scale-invariant mass $m(m)$ with a given precision
Parameters
epAbsolute target precision for the result
Returns
The scale-invariant mass

◆ to_SI()

double to_SI ( T &&...  t) const
inline

Compute the scale-invariant mass $m(m)$

Parameters
tAs in to_scale_invariant
Returns
The scale-invariant mass
See also
to_scale_invariant

◆ order()

int order ( ) const

Get the current order for the evolution of the mass

Returns
The running order

◆ nf()

int nf ( ) const

Get the number of active quark flavours

Returns
The number of flavours

◆ with_alpha_s()

Parameters with_alpha_s ( double  scale) const

Compute both the running mass and alpha_s at the given scale

Parameters
scaleTarget scale for the evolution
Returns
The values of alpha_s and the mass at the given scale

◆ error()

MSbar_mass& error ( double  err)

Set error bounds for evolution.

Parameters
errThe maximum absolute and relative error

◆ abs_error()

MSbar_mass& abs_error ( double  abs_err)

Set absolute error bound for evolution.

Parameters
errThe maximum absolute error

◆ rel_error()

MSbar_mass& rel_error ( double  rel_err)

Set relative error bound for evolution.

Parameters
errThe maximum relative error

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