Finite energy chiral sum rules and τ spectral functions -: art. no. 096014

A combination of finite energy sum rule techniques and chiral perturbation theory (chi PT) 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 chi PT quantity L-10. A constrained fit of R-tau,R- ((k, l)(V-A)) inverse moments (l <0) and positive spectral moments (l greater than or equal to 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 non-strange inverse moment chiral sum rules to one-loop order generalized chi PT. Our final result reads L-10(r)(M-rho,) = -(5.13 +/- 0.19) x 10(-3), where the error includes experimental and theoretical uncertainties. [S0556-2821(98)07221-X].