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arXiv · 0802.3591

Determination of the $ΔS = 1$ weak Hamiltonian in the SU(4) chiral limit through topological zero-mode wave functions

P. Hernandez·M. Laine·C. Pena·E. Torro·J. Wennekers·H. Wittig
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Abstract

A new method to determine the low-energy couplings of the $ΔS=1$ weak Hamiltonian is presented. It relies on a matching of the topological poles in $1/m^2$ of three-point correlators of two pseudoscalar densities and a four-fermion operator, measured in lattice QCD, to the same observables computed in the $ε$-regime of chiral perturbation theory. We test this method in a theory with a light charm quark, i.e. with an SU(4) flavour symmetry. Quenched numerical measurements are performed in a 2 fm box, and chiral perturbation theory predictions are worked out up to next-to-leading order. The matching of the two sides allows to determine the weak low-energy couplings in the SU(4) limit. We compare the results with a previous determination, based on three-point correlators containing two left-handed currents, and discuss the merits and drawbacks of the two procedures.

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P. Hernandez, M. Laine, C. Pena, E. Torro, J. Wennekers, H. Wittig. 2008-02-25. Determination of the $ΔS = 1$ weak Hamiltonian in the SU(4) chiral limit through topological zero-mode wave functions. https://doi.org/10.1088/1126-6708%2F2008%2F05%2F043

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