We use results of fits to the OPAL spectral data, obtained from nonstrange hadronic τ decays, to evaluate the difference between the vector and axial current correlators, ΠV-A(Q2). The behavior of ΠV-A(Q2) near Euclidean momentum Q2=0 is used to determine the effective low-energy constants L10eff and C87eff related to the renormalized low-energy constants L10r and C87r in the chiral Lagrangian. We also investigate how well two-loop chiral perturbation theory describes ΠV-A(Q2) as a function of Q2. This is the first determination of L10eff and C87eff to employ a fully self-consistent model for the violations of quark-hadron duality in both the vector and axial channels. We also discuss the values of the coefficients C6,V-A and C8,V-A governing the dimension-six and -eight contributions to the operator product expansion representation of ΠV-A(Q2). © 2013 American Physical Society.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 10 May 2013|