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arXiv · hep-ph/9802447

Finite Energy Chiral Sum Rules and Tau Spectral Functions

M. Davier·L. Girlanda·A. Hoecker·J. Stern
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Abstract

A combination of finite energy sum rule techniques and Chiral Perturbation Theory (ChPT) is used in order to exploit recent ALEPH data on the non-strange tau vector (V) and axial-vector (A) spectral functions with respect to an experimental determination of the ChPT quantity L_{10}. A constrained fit of R_{τ,V-A}^(k,l) inverse moments (l<0) and positive spectral moments (l>=0) adjusts simultaneously L_{10} and the nonperturbative power terms of the Operator Product Expansion. We give explicit formulae for the first k=0,1 and l=-1,-2 strange and non-strange inverse moment chiral sum rules to one-loop order generalized ChPT. Our final result reads L^r_{10}(M_ρ)=-(5.13 +/- 0.19)x10^{-3}, where the error includes experimental and theoretical uncertainties.

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M. Davier, L. Girlanda, A. Hoecker, J. Stern. 1998-02-27. Finite Energy Chiral Sum Rules and Tau Spectral Functions. https://doi.org/10.1103/physrevd.58.096014

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