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Title: The physics of hadronic tau decays

Abstract

Hadronic {tau} decays provide a clean laboratory for the precise study of quantum chromodynamics (QCD). Observables based on the spectral functions of hadronic {tau} decays can be related to QCD quark-level calculations to determine fundamental quantities like the strong-coupling constant, parameters of the chiral Lagrangian |V{sub us}|, the mass of the strange quark, and to simultaneously test the concept of quark-hadron duality. Using the best available measurements and a revisited analysis of the theoretical framework, the value {alpha}{sub s}(m{sub {tau}}{sup 2})=0.345{+-}0.004{sub exp}{+-}0.009{sub th} is obtained. Taken together with the determination of {alpha}{sub s}(M{sub Z}{sup 2}) from the global electroweak fit, this result leads to the most accurate test of asymptotic freedom: the value of the logarithmic slope of {alpha}{sub s}{sup -1}(s) is found to agree with QCD at a precision of 4%. The {tau} spectral functions can also be used to determine hadronic quantities that, due to the nonperturbative nature of long-distance QCD, cannot be computed from first principles. An example for this is the contribution from hadronic vacuum polarization to loop-dominated processes like the anomalous magnetic moment of the muon. This article reviews the measurements of nonstrange and strange {tau} spectral functions and their phenomenological applications.

Authors:
; ;  [1]
  1. Laboratoire de l'Accelerateur Lineaire, IN2P3/CNRS and Universite de Paris-Sud 11, BP34, F-91898 Orsay (France)
Publication Date:
OSTI Identifier:
21013699
Resource Type:
Journal Article
Journal Name:
Reviews of Modern Physics
Additional Journal Information:
Journal Volume: 78; Journal Issue: 4; Other Information: DOI: 10.1103/RevModPhys.78.1043; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6861
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHIRAL SYMMETRY; CHIRALITY; COUPLING CONSTANTS; HADRONS; LAGRANGIAN FUNCTION; MAGNETIC MOMENTS; MASS; MUONS; PARTICLE DECAY; QUANTUM CHROMODYNAMICS; QUANTUM ELECTRODYNAMICS; QUARK-HADRON INTERACTIONS; S QUARKS; SPECTRAL FUNCTIONS; STRONG-COUPLING MODEL; TAU PARTICLES; VACUUM POLARIZATION

Citation Formats

Davier, Michel, Hoecker, Andreas, and Zhiqing, Zhang. The physics of hadronic tau decays. United States: N. p., 2006. Web. doi:10.1103/REVMODPHYS.78.1043.
Davier, Michel, Hoecker, Andreas, & Zhiqing, Zhang. The physics of hadronic tau decays. United States. https://doi.org/10.1103/REVMODPHYS.78.1043
Davier, Michel, Hoecker, Andreas, and Zhiqing, Zhang. 2006. "The physics of hadronic tau decays". United States. https://doi.org/10.1103/REVMODPHYS.78.1043.
@article{osti_21013699,
title = {The physics of hadronic tau decays},
author = {Davier, Michel and Hoecker, Andreas and Zhiqing, Zhang},
abstractNote = {Hadronic {tau} decays provide a clean laboratory for the precise study of quantum chromodynamics (QCD). Observables based on the spectral functions of hadronic {tau} decays can be related to QCD quark-level calculations to determine fundamental quantities like the strong-coupling constant, parameters of the chiral Lagrangian |V{sub us}|, the mass of the strange quark, and to simultaneously test the concept of quark-hadron duality. Using the best available measurements and a revisited analysis of the theoretical framework, the value {alpha}{sub s}(m{sub {tau}}{sup 2})=0.345{+-}0.004{sub exp}{+-}0.009{sub th} is obtained. Taken together with the determination of {alpha}{sub s}(M{sub Z}{sup 2}) from the global electroweak fit, this result leads to the most accurate test of asymptotic freedom: the value of the logarithmic slope of {alpha}{sub s}{sup -1}(s) is found to agree with QCD at a precision of 4%. The {tau} spectral functions can also be used to determine hadronic quantities that, due to the nonperturbative nature of long-distance QCD, cannot be computed from first principles. An example for this is the contribution from hadronic vacuum polarization to loop-dominated processes like the anomalous magnetic moment of the muon. This article reviews the measurements of nonstrange and strange {tau} spectral functions and their phenomenological applications.},
doi = {10.1103/REVMODPHYS.78.1043},
url = {https://www.osti.gov/biblio/21013699}, journal = {Reviews of Modern Physics},
issn = {0034-6861},
number = 4,
volume = 78,
place = {United States},
year = {Sun Oct 15 00:00:00 EDT 2006},
month = {Sun Oct 15 00:00:00 EDT 2006}
}