QCD Library
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Implements the running and decoupling of the strong coupling constant. More...
Public Member Functions | |
strong_coupling (reference_coupling alpha_s=reference_coupling{}, int order=max_running_order) | |
double | operator() (double mu) const |
int | order () const |
int | nf () const |
strong_coupling | decouple_down (threshold thr) const |
Decouple down (remove) flavour in alpha_s. More... | |
strong_coupling | remove (threshold thr) const |
Remove (decouple down) flavour in alpha_s. More... | |
strong_coupling | decouple_up (threshold thr) const |
Decouple up (add) flavour in alpha_s. More... | |
strong_coupling | add (threshold thr) const |
Add (decouple up) flavour in alpha_s. More... | |
strong_coupling & | error (double err) |
Set error bounds for evolution. More... | |
strong_coupling & | abs_error (double abs_err) |
Set absolute error bound for evolution. More... | |
strong_coupling & | rel_error (double rel_err) |
Set relative error bound for evolution. More... | |
Static Public Attributes | |
static constexpr int | max_running_order = 4 |
Highest running order for the strong coupling. | |
static constexpr double | default_error = 1e-6 |
Default (relative and absolute) running error. | |
Implements the running and decoupling of the strong coupling constant.
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explicit |
Construct a new strong coupling
alpha_s | Reference value with the corresponding scale * and number of active flavours |
order | Running order between 0 and #max_order |
double operator() | ( | double | mu | ) | const |
Evolve the strong coupling to the given scale
mu | Target scale for the evolution |
int order | ( | ) | const |
Get the current order for the evolution of the coupling
int nf | ( | ) | const |
Get the number of active quark flavours
strong_coupling decouple_down | ( | threshold | thr | ) | const |
Decouple down (remove) flavour in alpha_s.
thr | The decoupling threshold |
strong_coupling remove | ( | threshold | thr | ) | const |
Remove (decouple down) flavour in alpha_s.
thr | The decoupling threshold |
strong_coupling decouple_up | ( | threshold | thr | ) | const |
Decouple up (add) flavour in alpha_s.
thr | The decoupling threshold |
strong_coupling add | ( | threshold | thr | ) | const |
Add (decouple up) flavour in alpha_s.
thr | The decoupling threshold |
strong_coupling& error | ( | double | err | ) |
Set error bounds for evolution.
err | The maximum absolute and relative error |
strong_coupling& abs_error | ( | double | abs_err | ) |
Set absolute error bound for evolution.
err | The maximum absolute error |
strong_coupling& rel_error | ( | double | rel_err | ) |
Set relative error bound for evolution.
err | The maximum relative error |