compute_running_alphas_rcl

compute_running_alphas_rcl(Q, Nf, lp)

Computes the value for alpha_s at the scale Q employing the renormalization-group evolution at lp loops (lp can take the value lp=1 or lp=2). The integer argument Nf selects the flavour scheme.

Parameters:
  • Q (float) – renormalization scale
  • Nf (int) – For Nf=-1 the variable flavour scheme is selected, where the number of active flavours contributing to the running of alpha_s is set to the number of quarks lighter than the scale Q. For Nf=3-6 the fixed Nf-flavour scheme is selected, where the number of active flavours contributing to the running of alpha_s is set to Nf. In this case Nf cannot be smaller than the number of massless quarks (otherwise the code stops).
  • lp (int) – loop-order, accepted values: 1,2