Variational perturbation theory and nonperturbative calculations in QCD

Journal Article · Tue Oct 15 04:00:00 EDT 2013 · Physics of Atomic Nuclei

DOI:https://doi.org/10.1134/S1063778813090196· OSTI ID:22212654

A nonperturbative approach based on the variational perturbation theory in quantum chromodynamics is developed. The variational series is different from the conventional perturbative expansion and can be used to go beyond the weak-coupling regime. The approach suggested takes into account the summation of threshold singularities and the involvement of nonperturbative light quark masses. Phenomenological applications of this approach to describe physical quantities connected with the hadronic {tau}-decay data: the R{sub {tau}} ratio, the light-quark Adler function, and the smeared R{sub {Delta}} function are presented. The description of examined quantities includes an infrared region and, therefore, they cannot be directly calculated within the standard perturbation theory. It is shown that in spite of this fact the approach suggested gives a rather good result for these quantities down to the lowest energy scale.

• OSTI ID: 22212654
• Journal Information: Physics of Atomic Nuclei, Journal Name: Physics of Atomic Nuclei Journal Issue: 10 Vol. 76; ISSN 1063-7788; ISSN PANUEO
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
COUPLING
D QUARKS
DECAY
EXPANSION
HADRONS
MASS
PERTURBATION THEORY
QUANTUM CHROMODYNAMICS
SINGULARITY
U QUARKS
VARIATIONAL METHODS