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arXiv · hep-ph/0503108

The < S P P > Green function and SU(3) breaking in K_{l3} decays

V. Cirigliano·G. Ecker·M. Eidemuller·R. Kaiser·A. Pich·J. Portoles
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Abstract

Using the 1/N_C expansion scheme and truncating the hadronic spectrum to the lowest-lying resonances, we match a meromorphic approximation to the < S P P > Green function onto QCD by imposing the correct large-momentum falloff, both off-shell and on the relevant hadron mass shells. In this way we determine a number of chiral low-energy constants of O(p^6), in particular the ones governing SU(3) breaking in the K_{l3} vector form factor at zero momentum transfer. The main result of our matching procedure is that the known loop contributions largely dominate the corrections of O(p^6) to f_{+}(0). We discuss the implications of our final value f_{+}^{K^0 π^-}(0)=0.984 \pm 0.012 for the extraction of V_{us} from K_{l3} decays.

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V. Cirigliano, G. Ecker, M. Eidemuller, R. Kaiser, A. Pich, J. Portoles. 2005-04-28. The < S P P > Green function and SU(3) breaking in K_{l3} decays. https://doi.org/10.1088/1126-6708%2F2005%2F04%2F006

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