Finite energy chiral sum rules and τ spectral functions
Abstract
A combination of finite energy sum rule techniques and chiral perturbation theory (χPT) is used in order to exploit recent ALEPH data on the nonstrange τ vector (V) and axialvector (A) spectral functions with respect to an experimental determination of the χPT quantity L_{10}. A constrained fit of R^{(k,l)}_{τ,VA} 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 formulas for the first k=0,1 and l=1 nonstrange inverse moment chiral sum rules to oneloop order generalized χPT. Our final result reads L^{r}_{10}(M_{ρ})=(5.13+/0.19)×10^{3}, where the error includes experimental and theoretical uncertainties.
 Publication:

Physical Review D
 Pub Date:
 November 1998
 DOI:
 10.1103/PhysRevD.58.096014
 arXiv:
 arXiv:hepph/9802447
 Bibcode:
 1998PhRvD..58i6014D
 Keywords:

 11.55.Hx;
 12.38.Lg;
 12.39.Fe;
 13.35.Dx;
 Sum rules;
 Other nonperturbative calculations;
 Chiral Lagrangians;
 Decays of taus;
 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment
 EPrint:
 LaTex, 20 pages, 5 figures (EPS)