Modified contour-improved perturbation theory

Journal Article · Mon Nov 01 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.82.093007· OSTI ID:21503770

Cvetic, Gorazd ^[1]; Loewe, Marcelo; Martinez, Cristian; Valenzuela, Cristian ^[2]

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1. Departamento de Fisica and Centro Cientifico-Tecnologico de Valparaiso, UTFSM, Valparaiso (Chile)
2. Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

The semihadronic tau decay width allows a clean extraction of the strong coupling constant at low energies. We present a modification of the standard ''contour-improved'' method based on a derivative expansion of the Adler function. The new approach has some advantages compared to contour-improved perturbation theory. The renormalization scale dependence is weaker by more than a factor of 2 and the last term of the expansion is reduced by about 10%, while the renormalization scheme dependence remains approximately equal. The extracted QCD coupling at the tau mass scale is by 2% lower than the contour-improved value. We find {alpha}{sub s}(M{sub Z}{sup 2})=0.1211{+-}0.0010.

• OSTI ID: 21503770
• Journal Information: Physical Review. D, Particles Fields, Vol. 82, Issue 9; Other Information: DOI: 10.1103/PhysRevD.82.093007; (c) 2010 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COUPLING
COUPLING CONSTANTS
EXPANSION
EXTRACTION
HADRONIC PARTICLE DECAY
MASS
MODIFICATIONS
PARTICLE DECAY
PERTURBATION THEORY
QUANTUM CHROMODYNAMICS
RENORMALIZATION
STRONG-COUPLING MODEL
DECAY
FIELD THEORIES
MATHEMATICAL MODELS
PARTICLE MODELS
QUANTUM FIELD THEORY
SEPARATION PROCESSES