Even after we have chosen a specific definition of the quantum-chromodynamic coupling constant (e.g., modified minimal subtraction or momentum-space subtraction) we are free to choose a definition of $\Lambda$ when we expand the coupling constant in powers of ${\left(\frac{\ln Q^2}{{\Lambda }^2}\right)}^{-1\mathrm{}}$. We discuss in detail a particular definition suggested by Abbott and argue that this definition does seem to provide an attractive means of fixing $\Lambda$.

• Received 20 October 1980

DOI:https://doi.org/10.1103/PhysRevD.23.1217