Abstracto
- The recent determination of the β-function of the quantum chromodynamics (QCD) running coupling to five-loops, provides a verification of the convergence of a novel method for determining the fundamental QCD parameter based on the light-front holographic approach to nonperturbative QCD. The new five-loop analysis, together with improvements in determining the holographic QCD nonperturbative scale parameter κ from hadronic spectroscopy, leads to an improved precision of the value of in the scheme close to a factor of two; we find Λ (3)/MS = 0.0339 ± 0.019 GeV for nf =3 , in excellent agreement with the world average, Λ (3)/MS = 0.0332 ± 0.017 GeV. We also discuss the constraints imposed on the scale dependence of the strong coupling in the nonperturbative domain by superconformal quantum mechanics and its holographic embedding in anti-de Sitter space.