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Title: Modified contour-improved perturbation theory

Abstract

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.

Authors:
 [1]; ; ;  [2]
  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)
Publication Date:
OSTI Identifier:
21503770
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 82; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.82.093007; (c) 2010 American Institute of Physics; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Cvetic, Gorazd, Loewe, Marcelo, Martinez, Cristian, and Valenzuela, Cristian. Modified contour-improved perturbation theory. United States: N. p., 2010. Web. doi:10.1103/PHYSREVD.82.093007.
Cvetic, Gorazd, Loewe, Marcelo, Martinez, Cristian, & Valenzuela, Cristian. Modified contour-improved perturbation theory. United States. https://doi.org/10.1103/PHYSREVD.82.093007
Cvetic, Gorazd, Loewe, Marcelo, Martinez, Cristian, and Valenzuela, Cristian. 2010. "Modified contour-improved perturbation theory". United States. https://doi.org/10.1103/PHYSREVD.82.093007.
@article{osti_21503770,
title = {Modified contour-improved perturbation theory},
author = {Cvetic, Gorazd and Loewe, Marcelo and Martinez, Cristian and Valenzuela, Cristian},
abstractNote = {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.},
doi = {10.1103/PHYSREVD.82.093007},
url = {https://www.osti.gov/biblio/21503770}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 9,
volume = 82,
place = {United States},
year = {Mon Nov 01 00:00:00 EDT 2010},
month = {Mon Nov 01 00:00:00 EDT 2010}
}