Running Coupling Explorer: α(μ) vs Energy Scale
Energy scale μ:
One-loop RG: QED (n
f
=3 leptons): 1/α(μ) = 1/α(μ₀) − n
f
·ln(μ/μ₀)/(6π), α(μ₀)=1/137 at μ₀=0.511 MeV.
QCD (N
c
=3, n
f
=5): 1/α
s
(μ) = 1/α
s
(μ₀) + (11N
c
−2n
f
)·ln(μ/μ₀)/(24π), α
s
(μ₀)=0.118 at μ₀=91.2 GeV.