Quantum-Chromodynamics Perturbation Expansions in a Coupling Constant Renormalized by Momentum-Space Subtraction

We relate two popular methods of renormalization; minimal subtraction and momentum-space subtraction. It is shown that $\frac{{\Lambda }_{\mathrm{mom}}}{{\Lambda }_{min}}=5.73\mathrm{}$, where $\Lambda$ is the mass used to parametrize the quantum-chromodynamic running coupling constant. Perturbation expansions are compared in the two methods. Our results support the conjecture that momentum-space subtraction leads to better convergence and that, therefore, ${\Lambda }_{\mathrm{mom}}$ is the parameter which should be measured by experiments.