Lattice QCD calculations

Due to the asymptotic freedom, the coupling constant of QCD is a diminishing function as the energy scale increases according to the following equation, already stated (*): . Therefore, the high-energy or equivalently the short-distance behavior can be described by a perturbative expansion, but a perturbative approach to the QCD fails at large distances where the begins to … Continue reading Lattice QCD calculations

Couplings and asymptotic freedom

Each of the four fundamental interactions can be characterized by a dimensionless parameter expressed in terms of universal constants, the coupling constant. In the lagrangian of strong interactions, the coupling constant is parameterized by the gauge coupling parameter,, giving in natural units . However, in a general field theory, the effective coupling constant is not a constant, … Continue reading Couplings and asymptotic freedom