Determination of the Chiral Couplings L10 and C87 from Semileptonic τ Decays González-Alonso, Martín Pich, Antonio Prades, Joaquim Strange quark mass Low-energy constants Us-vertical-bar Perturbation theory Spectral functions QCD predictions Hadronic width Using recent precise hadronic tau-decay data on the V-A spectral function, and general properties of QCD such as analyticity, the operator product expansion and chiral perturbation theory, we get accurate values for the QCD chiral order parameters L_10^r(M_rho) and C_87^r(M_rho). These two low-energy constants appear at order p^4 and p^6, respectively, in the chiral perturbation theory expansion of the V-A correlator. At order p^4 we obtain L_10^r(M_rho) = -(5.22\pm 0.06)10^{-3}. Including in the analysis the two-loop (order p^6) contributions, we get L_10^r(M_rho) = -(4.06\pm 0.39)10^{-3} and C_87^r(M_rho) = (4.89\pm 0.19)10^{-3}GeV^{-2}. In the SU(2) chiral effective theory, the corresponding low-energy coupling takes the value \overline l_5 = 13.30 \pm 0.11 at order p^4, and \overline l_5 = 12.24 \pm 0.21 at order p^6. 2013-11-06T08:15:14Z 2013-11-06T08:15:14Z 2008 info:eu-repo/semantics/article González-Alonso, M.; Pich, A.; Prades, J. Determination of the Chiral Couplings L10 and C87 from Semileptonic τ Decays. Physical Review D, 78(11): 116012 (2008). [http://hdl.handle.net/10481/29034] 1550-7998 1550-2368 doi: 10.1103/PhysRevD.78.116012 arXiv:0810.0760v2 http://hdl.handle.net/10481/29034 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License American Physical Society